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The user has requested enhancement of the downloaded file. Insect Ecology and Integrated Pest Management –ENTO-231 (2+1) – Revised Syllabus Dr. Cherukuri Sreenivasa Rao Associate Professor & Head, Department of Entomology, Agricultural College, JAGTIAL

EntoEnto----231231231231 Insect Ecology & IIIntegratedIntegrated Pest Management

Prepared by Dr. Cherukuri Sreenivasa Rao M.Sc.(Ag.), Ph.D.(IARI) Associate Professor & Head Department of Entomology Agricultural College Jagtial-505529 Karminagar District

Revised during 2010-11 Page Insect Ecology and Integrated Pest Management –ENTO-231 (2+1) – Revised Syllabus Dr. Cherukuri Sreenivasa Rao Associate Professor & Head, Department of Entomology, Agricultural College, JAGTIAL

ENTO 231 INSECT ECOLOGY & INTEGRATED PEST MANAGEMENT

Total Number of Theory Classes : 32 (32 Hours) Total Number of Practical Classes : 16 (40 Hours) Plan of course outline: Course Number : ENTO-231 Course Title : Insect Ecology & Integrated Pest Management Credit Hours : 3(2+1) (Theory+Practicals) General Objective : To impart knowledge to the students on the ecology of insects and various methods of pest management Course In-Charge : Dr. Cherukuri Sreenivasa Rao Associate Professor & Head Department of Entomology Agricultural College, JAGTIAL-505529 Karimanagar District, Andhra Pradesh Academic level of learners at entry : I Year B.Sc.(Ag.) Academic Calendar in which course offered : II Year B.Sc.(Ag.), I Semester Course Objectives: Theory: By the end of the course, the students will be able to know the influence of ecological factors on insect development and distribution, understand componenets of integrated pest management, know the classification of insecticides, and their use in pest management, and understand the mass multiplication techniques of major bio-agents. Practicals: By the end of practical exercises, the students will be able to know the sampling techniques for estimation of insect populations, know about light traps, pheromone traps and insecticides in pest management, identify biological agents, know insecticide formulations and dosage calculation, and acquaint with mass multiplication of bio-agents. MARKS Distribution Type of Examination Allotted Marks Mid-Semester Exam 40 Theory Semester Final Examination 60 Theory-TOTAL 100 Class Work-Practical Record 15 Class Work-Insect Collection 10 Practicals Class Work -TOTAL 25 Final Practical Examination-Written Examination 20 Final Practical Examination-Viva Voce 05 Final Practical Examination-TOTAL 50 TOTAL (Theory+Practicals) (100+50) • Total 150 marks will be reduced to 100 (reduced to 10 for calculation of 150 Grade Point) • Grade Point (GP) in course should be 5.0/10.0 to PASS in the course Points to Remember • Student should get 50% of marks to PASS in Final Theory Examination • Student should get 50% of marks to PASS in Final Practical Examination • Student should get 5.0 GP to PASS in the Course 2

Theory-Lecture Wise outlines (As per the Green Book of 2010) 1. Ecology-introduction- autecology and synecology-population, community-importance of insect ecological studies in IPM. Environment and its components-soil, water, air and biota. 2. Abiotic factors- temperature -its effect on the development, fecundity distribution, dispersal and movement of insects-adaptation of insects to temperature-thermal constant. 3. Moisture - adaptation of insects to conserve moisture-humidity-its effect on development, fecundity and colour of body-Rainfall - its effect on emergence, movement and oviposition of insects. 4. Light -phototaxis, photoperiodism-its effect on growth, moulting activity or behavior, oviposition and pigmentation, use of light as a factor of insect control; Atmospheric pressure – its effect on behaviors; Air currents - effect on dispersal of insects-edaphic factors-water currents. 5. Biotic factors-Food -classification of insects according to nutritional requirements-other organisms -inter and intra specific associations-beneficial and harmful associations of parasitoids based on site of attack, stage of attack, duration of attack, degree of parasitism and food habits. 6. Concepts of balance of life-biotic potential & environmental resistance- normal coefficient of destruction-factors contributing to increase or decrease of population-causes for outbreak of pests in agro-ecosystem-explantation for causes (Intensive use of N fertilizers, Indiscriminate use of pesticides, Use of high yielding varieties and introduction of new crops, Destruction of forests and bringing forest area under cultivation, Monoculture, Introduction of a new pest in a new area, Accidental introduction of foreign pests, Destruction of natural enemies and Large scale storage of food grains). 7. Pest Surveillance-definition-importance in IPM and its advantages-components of pest surveillance-pest forecasting-types of forecasting (long-term & short-term forecasting-their advantages)-insect pests-defintions of negligible, minor and major pests; different categories of pests-regular, occasional, seasonal, persistent, sporadic, epidemic and endemic pests with examples. 8. Integrated pest management (IPM)-introduction-importance-evolution on IPM, collapse of control systems, patterns of crop protection and environmental contamination-concepts & principles of IPM-economic threshold level (ETL), economic injury level (EIL), general equilibrium position (GEP)-components/tools of IPM-practices, scope and limitations of IPM. 9. Host plant resistance-principles of host plant resistance-ecological resistance-phonological asynchrony, induced resistance & escape-genetic resistance-mono, oligo and polygenic resistance, major (vertical-specific-qualitative) or minor (horizontal-non-specific-quantitative) gene resistance-host plant selection process-host habitat finding, host finding, host recognition-host acceptance & host suitability-mechanisms of genetic resistance-antixenosis, non-preferences (antexenosis), antibiosis and tolerance-transgenic plants. 10. Importance and history crop losses due to pests-plant protection measures in India-methods of pest control-natural and applied (preventive & curative methods)-cultural, mechanical, physical, legislative, biological and chemical methods. 11. Cultural control-normal cultural practices which incidentally control the pests and cultural practices recommended specifically against certain pests. Mechanical control-different mechanical methods of pest control with examples. 12. Physical control-use of inert carriers against stored product insects-steam sterilization-sterile male technique-solarization-solar radiation-light traps-flame throwers etc . Legislative measures-importance of quarantine-examples of exotic pests-different legislative measures enforced in different countries and also in India in restricting the movement of agricultural products with in the country and to outside. 13. Biological control-types of biological control-introduction-augumentation and conservation- parasite-parasitoid-parasitism-grouping of parasites based on nature of host, stage of host, site of parasitization, duration of parasitization, degree of parasitization & food habits-number of hosts attacked-kinds of parasitism-qualities/attributes of an effective parasite to be successful

biological agent. 3

14. Biological control-predators-predatism-qualities of insect predator-differences between predator and a parasite-mass multiplication of important insect parasitoids ( Trichigramma, Bracon, Tetrastichus ) and predators (Chrysoperla, Cryptolaemus, Cheilomenes ). 15. Microbial control-bacteria, viruses, fungi and protozoa-important species of micro-organisms against major pests for incorporation in IPM-mass multiplication of Metarrhizium, Nomureae, Beauveria and Nuclear polyhedrosis virus (NPV). 16. Microbial control-entomopathogenic nematodes (EPNs) important species-mode of infectivity and examples-mass multiplication. Biological control of weeds with insects-advantages & disadvantages of biological control. 17. Beneficial insects-important species of pollinators-caprification-pollination syndromes-factors that affect pollination-weed killers-successful stories-scavengers their importance. 18. Chemical control- importance and ideal properties of insecticides, classification of insecticides on the basis of origin, mode of entry, mode of action and toxicity-toxicity evaluation of insecticides, acute and chronic toxicities, oral and dermal toxicities, LC 50 (lethal concentration) , LD 50 (leathal dose) , ED 50 (effective dose), LT 50 (lethal time), KD 50 (knockdown dose), KT 50 (knockdown time)-bioassay methods. 19. Formulations of insecticides-dusts, granules, wettable powders, water dispersable granules, solutions, emulsifiable concentrates, suspension concentrates, concentrated insecticide liquids, fumigants, aerosols, baits and mixtures of active ingredients. 20. Inorganic insecticides-arsenic Compounds, fluorine and sulphur compounds; plant derived insecticides- neem based products-different commercial formulations containing azadirachtin, neem seed kernel extract, neem cake extract and their uses-nicotine-rotenon-plumbagin and pyrethrum-source, properties & uses. 21. Synthetic organic insecticides-chlorinates hydrocarbons-DDT, HCH-cyclodiens-aldrin, dieldrin, chlordane, heptachlor and endosulfan-toxicity & mode of action. 22. Organo phosphates-systemic, non-systemic and translaminar action with examples-brief mode action-toxicity, formulations & uses of malathion, methyl parathion, diazinon, dichlorvos, fenitrothion, quinalphos, phosalone, chlorpyriphos, phosphomidon, monocrotophos, methyl demeton, dimethoate, triazophos, profenphos, acephate and phorate. 23. Carbamates-mode of action-toxicity, formulations & uses of carbaryl, propoxur, carbofuran, aldicarb, methomyl-insecticides with nematicidal and acaricidal properties. 24. Synthetic pyrethroids-brief mode of action-toxicity, formulations & uses of allethrin, resmethrin, bioresmethrin, bioallethrin, fenvalerate, permethrin, deltamethrin, cypermethrin, lambda-cyhalothrin, cyfluthrin, fenpropathrin, flucythrinate, fluvalinate, fenfluthrin. 25. Insecticides of other groups-fixed oils; novel insecticides-nicotinoid insecticides-brief mode of action-toxicity, formulations & uses of imidacloprid, acetamiprid, thiamethoxam & clothianidin; phenyl pyrazoles-brief mode of action-toxicity, formulations & uses of fipronil. 26. Macrocyclic lactones-spinosyns-brief mode of action, toxicity, formulations & use of spinosad; avermectins-brief mode of action, formulationas & use of abamectin and emamectin benzoate; oxadaizines-brief mode of action, formulation & use of indoxacarb; thioureas- brief mode of action, formulations & use of diafenthiuron; pyridine azomethines-brief mode of action, formulations & use of pymetrozine; pyrroles-brief mode of action, formulations & use of chlorfenapyr and f lubendiamide. 27. Formamidines- brief mode of action, formulations & use of chlordimeform & amitraz; ketoenols-brief mode of action, formulations & use of spirotetramat, spiromesifen & spirodiclofen. 28. Chitin synthesis inhibitors-brief mode of action, formulations & use of diflubenzuron, flufenoxuron, chlorfluazuron, triflumuron, teflubenzuron, lufenuron, hexaflumuron, flucyclouron, novaluron & buprofexin.; juvenile hormone (JH) mimics- brief mode of action, formulations & use of juvabione, methoprene, hydroprene, kinoprene; JH agonists- brief mode of action, formulations & use of pyriproxyfen, fenoxycarb; ecdysone agonists- brief mode of action, formulations & use of methoxyfenozide, halofenozide & tebufenozide. 29. Recent methods of pets control- repellants (physical and chemical repellents); antifeedants- importance of antifeedants and limitations of their use; sex pheromones-definition, list of 4

pheromones available-use in IPM; insect hormones-moulting and juvenile hormones; gamma radiation- principles and limitations; genetic control- principles and its limitations; sterile male technique. 30. Rodenticides- zincphosphide, aluminum phosphide, bromodilone; acaricides- sulphur, dicofol, tetradiform; fumigants- aluminum phosphide. 31. Application techniques of spray fluids- high volume, low volume and ultra low volume sprays; phytotoxic effects of pesticides-advantages and limitations of chemical control-safe use of insecticides. 32. Symptoms of poisoning, first aid, antidotes for the important groups of insecticides; insecticide resistance, insecticide resurgence, insecticide residues-importance-maximum residue limits (MRL)-average daily intake (ADI), waiting periods, important provisions of Insecticides Act 1968. Practicals: 1. Visit to meteorological observatory/ automatic weather reporting station. 2. Study of terrestrial and aquatic ecosystems of insects. 3. Study of behavior and orientation of insects- repellency, deterrancy and stimulation. 4. Study of distribution patterns of insects in crop ecosystems. 5. Sampling techniques for the estimation of insect population. 6. Sampling techniques for the estimation of insect pest damage. 7. Pest surveillance through light traps, pheromone traps and field scouting. 8. Forecasting of pest incidence. 9. Acquaintance of insecticide formulations. 10. Calculation of doses/ concentrations of different insecticidal formulations. 11. Compatibility of pesticides with other agro chemicals and phytotoxicity of insecticides. 12. Acquaintance of mass multiplication techniques of important predators-Cheilomenes, Chrysoperla, and Cryptolaemus. 13. Acquaintance of mass multiplication techniques of important parasitoids-egg, larval and pupal parasitoids. 14. Acquaintance of mass multiplication techniques of important entamopathogenic fungi. 15. Acquaintance of mass multiplication techniques of NPV. 16. Study of pollinators, weed killers and scavengers. Note: Submission of well maintained insect specimens during the final practical examination is compulsory.

LIST OF REFERENCE BOOKS:

• Integrated Pest Management-Concepts and Approaches : Dhwaliwal GS and Ramesh Arora (2001), Kalyanai Publishers, Ludhiana. • Biological Pest Suppression ; Gautam RD (2008), Westville Publishing House, New Delhi. • Introduction to Insect Pest Management ; Metcalf RL and Luckman WH (1982), Wiley Inter Science Publishing, New York. • General and Applied Entomology ; Nair KK, Ananthakrishnan, TN and David BV (1976), Tata McGeaw Hill Publishing Company Ltd, New Delhi. • Entomology and Pest Management ; Larry E Pedigo and Marlin E Rice (1991), Prentice Hall of India Private Ltd, New Delhi. • Principles of Insect Pathology ; Steinhaus EA (1949), McGraw Hill Book Co., New York. • Integrated Insect Pest Management ; Venugopala Rao N, Umamaheswari T, Rajendraprasad P, Naidu VG and Savitri P (2004), Agrobios (India) Limited, Jodhpur. • Elements of Insect Ecology ; Yazdani SS and Agarwal ML (1979), Narosa Publishing House, New Delhi. • A Text Book of Applied Entomology (Vol I & II) ; Srivatsava KP (1996), Kalyani Publishers, Ludhiana. • Botanical and Biopesticides ; Parmar BS and Devakumar C (1994), Westvill Publishing House, New Delhi. • Plant Protection Techniques ; Chaterjee PB (1997), Bharati Bhavan, New Delhi. • Insecticides :Toxicology & Uses; Gupta HCL (1998), Agrotech Publishing Academy, Udaipur. • Alternatives to Chemical Pesticides in Pest Management ; Gupta HCL (2008), Agrotech Books, Udaipur. • Integrated Pest Management and Biocontrol ; Dwivedi SC, Dwivedi Nalini (2006), Estern Book Corporation, Kolkata • Ecologically Based Integrated Pest Management ; Opender Koul and Gerrit W Cuperus (2007), CABI Publishing. • Insect Ecology ; Peter W Price (1997), Wiley. • Insect Ecology ; Prakash M (2008), Discovery Publishing House Pvt Ltd. • Ecology ; Odum (1975), Oxford & IBH Publishing Co. • Fundamentals of Ecology ; Odum Eugene (1996), Natrraj Publishers.

Instructions: • Text given in highlighted format and italics format is important to remember for examination purpose.

• Text given in small font (size 10.5) includes additional information related to the same lecture, which can be utilized by teacher and student for learning important points.

Lecture: 1 Ecology-introduction- autecology and synecology-population, community-importance of insect ecological studies in IPM. Environment and its components-soil, water, air and biota.

• The word ecology is the modified form of oekologie derived from greek word oikos, meaning home , and logos meaning discourse/study introduced by Reiter in 1868, and later anglicized to ecology . • Haeckel (1869) defined Animal Ecology-as the body of knowledge concerning the economy of nature-the investigations of total relations of animals to their inorganic and organic environment. • Elton (1927) defined animal ecology-scientific natural history, concerned with sociology and economics of animals. His concept of key-industry animals (hervivores) integrating the community through food chains, focused attention on the interactions among various animals. • The concept of communities (plants and animals) led to more précised definition by Shelford (1929) who defined ecology as the science of communities . • As defined by Allee et al (1949): ecology is the science of interrelation between the living organisms and their environment , including both the physical and the biotic environments and emphasizing interspecies as well as intraspecies relations. • Odum (1953) defined ecology as the study of the structure and functions of nature . • Ecology can be defined as the scientific study of interactions that determine the distribution & abundance of organisms . • Ecology, study of the relationships of organisms to their physical environment and to one another . • Ecology is the study of the relationships between organisms and their environment . • Insect Ecology may be defined as the understanding of physiology and behavior of insects as affected by their environment. • The study of an individual organism or a single species is termed autecology . • The study of groups of organisms is called synecology . • In nature, living organisms and the nonliving substances of the environment interact upon each other to produce an exchange of materials / energy between living and nonliving components. Such ecological system was given the name ecosystem (Tansley, 1935). So, the functioning of ecosystem can only be understood through the study of various communities that form its part. The plant-animal complex in a community is the sum total of the inter-relations between organisms and their physical environment. It is a dynamic study involving ecological succession as well. • Ecology is the multi-disciplinary subject, and derives support from such sciences as animal biology, taxonomy, physiology, animal behavior, meteorology, geology, physics, chemistry and even sociology. Many branches of ecology such as physiological ecology, behavioral ecology, community ecology, ecosystem ecology, applied ecology, theoretical ecology etc. have been evolved based on the specific objectives of the studies. • Ecology can be defined as the scientific study of interactions that determine the distribution & abundance of organisms . Distribution refers to where organisms are found. We can study distribution on different scales: where found geographically where found in terms of habitat how distributed spatially within habitat 7

Abundance refers to how many organisms occur. We can ask different questions about abundance: does a species occur in many habitats ? If so, it will appear abundant on a large scale -we will encounter it in many places. are there large numbers of individuals of a species in a habitat where it occurs? If so, a species may be rare or abundant on a large scale, but in certain localities it will be abundant. we can also look at abundance in terms of numbers of species, rather than in terms of individuals of a single species. We can ask whether an area has many different species or only a few species. Interactions refer to the relationships between an organism or species and aspects of its environment.

The above explanations of distribution, abundance, and interactions should indicate that we can study ecology on a various different levels. The main levels studied by ecologists are: Individuals: We can consider how individuals are affected by the environment; this can determine whether they can survive (which will affect their distribution) and how well they reproduce (which will affect their abundance.) Populations: A population is a group of organisms of the same species within a defined area. We can look at the factors that determine how large a population grows, that regulate it at a certain size, or that cause population size to fluctuate. Communities: A community usually refers to all the organisms within an area. We can also talk about a community of some type of organism, such as the community of rodents in a paddy field in West Godavari. Ecosystems: An ecosystem refers to all the organisms within an area and the abiotic factors that affect it. Ecosystem or ecological system is the functioning together of community and the non-living environment where continuous exchange of matter and energy takes place. In other words, ecosystem is the assemblage of elements, communities and physical environment.

Cells Organs Organisms Populations Communities

Matter Energy

Cell Organ Organism Population ECOSYSTEM System System System System

Habitat is the place where the organisms live. Scientific study means using the scientific method, is an important part of the definition of ecology because it indicates that to study ecology we must be doing the things associated with science-testing hypothesis with objectively obtained, repeatable data. For making a scientific approach to the study of ecology at all the levels viz., individual, population, community and ecosystem, it is essential to understand the various factors of the environment . Climate constitutes the physical factors which

exert their influence on all the organisms. Food and other organisms of the same and other species are the other important factors. • The environment refers to the surroundings of an organism or species or sum of everything that affects the organism, and is generally considered to consist of two categories of factors: Abiotic ( Density independent factors) & Biotic factors ( Density dependant factors) .

Environment (surroundings of an organism or species or sum of everything that affects the organism)

Abiotic components Biotic components (Non-Living things) (Living things) (Density independent factors) (Density dependant factors)

Atmosphere Hydrosphere Lithosphere Biosphere Producers Consumers De-composers

• Abiotic factors refer to nonliving aspects of the environment that affect an organism, such as temperature, moisture and humidity, rainfall, light, atmospheric pressure, air currents, water, oxygen, pH, salinity, place to live etc.. • Biotic factors refer to other organisms that interact with an organism or species, or the organic products of those organisms. Examples of biotic factors include: the species that produce the food ( primary producers ) eaten by an organism, species that feed on and harm the organism (consumers ), including: predators : species that kill and eat their prey and have no long term interaction with them, parasites : species that live on or in their host over a long period of time and harm, but are unlikely to directly kill, the host, parasitoids : species whose eggs are laid on the host (typically on the larval stages of insect hosts) and which then develop in or on the host, harming it as parasites do, but that eventually grow large and kill the host, brood parasites : species (typically birds) that lay eggs in the nests of their host species. The hosts care for these young and their own young are usually harmed or killed, interspecific competitors of the organism -other species that use the same resources and deplete supplies of those resources so that they negatively impact an organism, mutualists -species whose presence is helpful or essential to the organism, and who are helped by the organism, members of same species , through: intraspecific competition: use of same resources, so members of same species affect each other negatively, behavioral interactions. • Note that biotic and abiotic factors interact. For example, plants (biotic factors) in an environment tend to increase the amount of oxygen (an abiotic factor.)

Lecture: 2 Abiotic factors- temperature-its effect on the development, fecundity distribution, dispersal and movement of insects-adaptation of insects to temperature-thermal constant.

ABIOTIC FACTORS: • These factors are also known as physical factors, are non-living and density independent factors. • Various physical factors of the environment have direct influence on animal distribution and abundance, and these include:

Abiotic factors Physical factors Non-living factors Density independent factors

Temperature Moisture & Humidity Rainfall

Light

Atmospheric Pressu re

Air currents

Water

Place to live (niche)

• To study effect of physical parameters on animals, first the effect of each component of the environment has to be investigated separately by keeping the other components constant, and such studies are possible only under laboratory conditions. For example, we can study the influence of temperature on the rate of development, fecundity and longevity of insect by keeping other parameters constant.

TEMPERATURE: • Temperature directly influences the distribution of insects in nature, because certain amount of warmth is essential for growth and reproduction. This is the most important physical factor of the environment. • It affects directly on the dispersal, distribution, movement, development, metabolism, fecundity and reproduction which determine the abundance of the insect and also indirectly through influence on food availability (crops) and other environmental factors such as moisture, air movement etc. • With few exceptions, all the developmental activities ceases at about 0 oC, similarly beyond certain high temperatures, animals cannot live. The range of favorable temperatures for any particular species depends on the prevailing conditions under which the insect usually lives. Generally speaking, terrestrial animals have a wider

range of favorable temperatures than the aquatic animals.

Based on the maintenance of body temperatures, animals are generally divided into • Warm blooded (Homeothermic, Endothermic) animals maintains the body temperatures constant irrespective of atmospheric temperatures. Ex: Mammals, Birds. • Cold blooded (Poikilothermic, ectothermic) animals change their body temperature when the atmospheric temperature changes. Ex:Insects • Sociohomeothermic animals such as honey bees can able to maintain their body temperatures slightly above the atmospheric temperatures, and are able to air condition their nests. They maintain their own temperatures inside their colony irrespective of the temperature outside. Temperature and Insect Development: • In general, it is convenient to discuss the effect of temperatures in three zones viz., Zone of effective temperature (temp preferendum-favourable range), Zone of inactivity and lethal / fatal zone. • The growth of cold blooded or poikilothermic animals is arrested at 10 oC and this temperature is called developmental zero or threshold development. • The optimum temperature for the normal development of insects is 10-35 oC and is known as Zone of Optimum or Normal Development. • The different temperature zones from low to high are:

Zone of Zone of Zone of Zone of Fatal Low inactivity Zone of effective temperature inactivity fatal high Temperature due to low (10 oC-35 oC) due to high temperature (-14 oC to -5oC) temperature Temperature Preferendum temperature (50-60 oC) (-5oC-10 oC) (35 oC-50 oC)

-14 oC -5oC 10 oC 35 oC 50 oC 60 oC

Max fatal Minimum Optimum temperature Maximum Maximum temp effective (10 oC-35 oC) effective fatal (-14 oC) temp or temp or Temp threshold of threshold of (60 oC) development development (10 oC) (35 oC)

• Zone of effective temperature (10-35 oC): Active development takes place in this zone (temperature preferendum ); at minimum effective temp or threshold of development, the development ceases and on ascending scale the development starts, while at maximum effective temperature or upper vital limit or threshold of development, the development ceases and on descending scale the development starts. • Zone of inactivity (-5oC to 10 oC, and 35 oC to 50 oC): The are the zones immediately below and above the threshold of development, and in these zones the insect will live but without development, and they can recover if removed to favorable temperatures. • Zone of fatal temperatures (-5oC to -14 oC, and 50 oC to 60 oC): The zone is fatal for insects, and cannot survive and die. • If the insect is given a choice to move along a temperature gradient, it prefers a narrow limit of temperature known as temperature Preferendum or preferred temperature . • Certain insects do not get freezes even the surrounding temperatures go below the freezing point ( cold hardiness/super cooling ). These insects have cryoprotective compounds like glycerol, sorbitol and erythritol which help insects not forming ice crystals in haemolymph by depressing the freezing point. The freezing point of most insects is between -10 0C to -2oC. It is observed that when a cold-hardy insect is chilled the body tissue do not freeze immediately. Dehydration also enhances the cold hardiness. The tropical stored-grain pests lack these capabilities. Under unfavorable

temperatures, insects suspend their activities, and these are two types. 11

• Hybernation is the period of suspended activity in individuals occurring during seasonal low temperatures, while Aestivation is a period of suspended activity in individuals occurring during seasonal high temperatures or in dry season. This reversible inactivity can last for number of weeks during winter and summer, respectively. As soon as the temperature becomes moderate, these insects resume activity. It is claimed that a logistic curve completely expresses the relation between the temperature and the speed of the development. It has the form of a flattened letter “S” and therefore, is called a “Sigmoid Curve”. Temperature and Fecundity: • In insects, fecundity (egg laying ability) is maximum at moderately high temperatures and decline at both upper and lower limits of favorable temperature. • Aphids remain parthenogenetic under high temperatures and many hours of sunshine while the opposite condition gives rise to oviparous forms. • If the number of days required to hatch eggs of an insect species are plotted against the temperature at which are kept, the points would fall along a symmetrical curve that resembles a hyperbola. Temperature and Insect Distribution: • Tropical and sub-tropical conditions like in India are favourable for distribution and establishment of insects. • Mediterranean fruit fly Ceratitis capitata (Tephritidae-Diptera) could not establish in England and North Europe, because it cannot withstand temperature below 10 oC. • Mosquitoes (Culicidae-Diptera) are abundant at 70-80 oF (=10 oC) but are rare at 100- 113 oF (30 oC). • Cotton Pink Bollworn Pectinophora gossypiella (Gelechidae-Lepidoptera) is serious pest and abundant in the Punjab state where temperature is 95.5 oF during August- September, and is non-abundant in adjoining Western Pakistan due to high temperatures, 99 oC (23 oC) during August-September. Temperature and Dispersal: • Insects tend to move away from unfavorable temperatures. • The rice weevil Sitophilus oryzae (curculionidae:coleoptera) found in the upper layers of storage bins, because the inner layers are warm and it cannot tolerate beyond 32 oC and hence adults migrate to upper layers of the bins. • Desert Locust Schistocerga gregaria (acrididae-orthoptera) start gathering in basking groups to gain warmth and they take flight only when the temperature near the ground is between 17-22 oC and stop migrate when the temperature goes down to 14-16 oC. Adaptations to Temperatures (Acclimatization): • The effect of temperature on growth can be quite complicated or subtle. • In other words, the reaction to a certain changed temperature depends on whether that change has been brought gradually or suddenly. By a gradual change, the insects become conditioned and that conditioning is called acclimatization or acclimation. Based on the experiments conducted by various scientists suggests that the rate of acclimatization is dependent on the duration for which they are conditioned , and also depends upon whether the change in temperature is brought about suddenly or gradually. • At high temperatures, locusts expose minimum body surface to sun rays by lying parallel to them (changes body angle) while they expose maximum body surface to sun rays at low temperatures laying at right angles to them.

Thermal Constant: • The total heat energy required to complete a certain stage of development in the life- history of a species or in the completion of the physiological process is constant, and is termed as thermal constant, as developed by Simpson (1903), and will be expressed in day/hour degrees. • Within favorable range, it is not affected by the level of temperature and, as such, can be measured as a day-degree i.e. one degree of mean temperature lasting for one day. • Uvarov (1931) developed a mathematical formula to correlate the period of development with heat. C=D(T-K), where C is thermal constant D is duration of stage T is temperature during the stage K is threshold of development, and T-K is effective temperature. Notes:

Lecture: 3 Moisture - adaptation of insects to conserve moisture-humidity-its effect on development, fecundity and colour of body-Rainfall - its effect on emergence, movement and oviposition of insects.

MOISTURE • In nature, insects are found under a wide range of moisture conditions from fresh water to the driest sun-dunes in deserts. • For a given species, however, the range of moisture requirements is not so wide, living within that range; they maintain their body water at a fairly constant level. In aquatic animals, the dryness is expressed in terms of osmotic pressure of the water. The truly terrestrial insects can live in dry places under varying conditions of moisture. Collembola live in very humid places where air is always saturated with moisture. At the other extreme, the desert insects, which can survive in air containing less than 10% moisture. Since food is the source practically for all insects, their feeding habits reflects adaptations to cope with conditions of excessive moisture or shortage of water. For example, aphids and bugs, ingest large quantities of plant sap and get rid of excessive water through excretion and also special arrangement in digestive system (filter chamber). On the other hand, those living on dry foods such as grains do not get sufficient water. For example, Ephestia larvae could live in flour dried at 103 oC. This led to discovery that these insects could retain body water through metabolism. • Of various forms of water, the vapor form plays important role in life of terrestrial organisms. A certain amount of atmospheric humidity is essential for controlling the loss of water from body. If the humidity is low, the animals die from desiccation at high temperature, and if the humidity is too high, it may harm in many ways, including the development of fungi and bacteria epizootics. • Water is essential constituent of protoplasm, i.e. life, though the actual quantities vary in different insects. For example in Tribolium, Sitophilus, Trogoderma and Callosobruchus , which are pests of stored grains; water constitutes 50% of their body weight. However, bodies of most of insects contain 80-90% water and larvae of certain dipteran that live in moist surroundings contain up to 98% water. The phytophagous insects live on food that has plenty of water and it is taken up by the insect as such.

Adaptations to conse rve water in body

Morphological adaptations

Body pigmentation

Integument

Pilocity / hairiness

winglessness

Form of the body

Other characters

Biological adaptations

Physiological adaptations

Adaptations to conserve water: • Among terrestrial insects there are a number of other adaptations help them overcome unfavourable conditions of aridity or excessive moisture, and such adaptations may be morphological, biological and physiological. 1. Morphological adaptations: • Body pigmentation : In colder regions, and on the mountains, insects usually have darker body pigmentation; whereas those in deserts are generally lighter in colour. Dark colour helps to absorb the sun light which raises the body temperature, helps in removing the excessive moisture in the insect body. The lighter body colour of desert insects helps in saving the insect from moisture loss through light reflection. • Integument: A tough integument with fused sclerites and shield like pronotum of many coleopterans helps in water / moisture conservation, since most of them live in dry habitats and feed on dry foods. Waxy coating on body of some insects also helps in water conservation. • Pilocity (Hairyness): A dense growth of hair on the body is common in many desert insects, which saves them from excessive evaporation and also aids in reflecting the sun light. • Winglessness: Grasshoppers and Crickets which are commonly found in arid regions and semi-deserts have generally poorly developed wings and some are wingless. For example, the Phadka Grasshopper in Western India shows variation in size of wings and the Deccan Grasshopper is wingless altogether. In the desert areas of Africa, about half of the Orthoptera found are wingless. In some species of Tenebrionid and Carabid beetles, the wings are fused. This adaptation protects the insect against the effect of strong hot desert winds. • Form of the body: The oval and compressed form of the body found in number of desert beetles allows the least amount of body surface being exposed to the surroundings. Moreover, they can seek shelter under stones, creeks and crevices. • Other characters: A number of cicindelid and carabid beetles found in the desert have long and slender legs , with help of which they can walk on hot sand, without touching their bodies to sand. Other desert insects have strong legs for burrowing in sand , so they can burrow and bury themselves at faster rate, thus, escaping the desiccation by reducing the period of exposure. 2. Biological adaptations: • In general, the life-cycles of insects are in tune with environmental conditions. In summer, many delicate insects enter aestivation or are in diapauses. • The pupa of Red Hairy Caterpillar, Amsacta moorei is in diapauses during autumn and winter and even part of next summer when dry conditions prevail. With the first shower in june/july, the pupae absorb moisture which is essential for breaking diapauses, and moths emerge and lay eggs. • Groundnut red hairy caterpillar Amsacta albistriga (Arctidae-Lepidoptera) enter into aestivation when dry conditions prevail. • Similarly, there is a diapuse in summer in number of grasshoppers. 3. Physiological adaptations: • Cryptonephric condition for re-absorption of water from products of excretion so as to conserve water is present in meal worm Tenebrio molitor and many other coleopterans and lepidopterans.

Influence of humidity on development, fecundity etc.: • The fall of water content of body below certain minimum proves disastrous to insects and if it is considerably above the normal (in wet places) harmful effects like viral, fungal and bacterial disease outbreaks occur. • The phenomenon of humidity preferendum is another important factor. If the insects are given a choice to move freely in a humidity gradient with complete dryness on one end and the saturated air on the other, they have tendency to congregate within narrow range of humidity and that range is the preferred humidity. The humidity influences the rate of development, fecundity and color etc., in different insects. • At an unfavorable humidity, the insect dies before completing its development. Even within the favourable range, all insects do not react the same way. There are three types: those in which the speed of development is retarded at high humidity (the nymphs of Locusta and Schistocerca ), those have an accelerated development at high humidity (eggs of Locusta and Musca ), those which have a rate of development independent to humidity (the embryonic development in the eggs of Bruchus not influenced by humidity). Generally, if the water content of the body is high, dry air accelerates the development. • The adults of Locusta migratoria and Schistocerca gregaria become sexually mature quicker at a certain RH (about 70%) than in atmosphere too dry or too humid. • The number of eggs laid by a female increases as the humidity increases upto 70% and declines again at 90%. On the other hand, fecundity of the rice weevil, Sitophilus oryzae increases steadily upto 70% humidity, but there is no decline in the number of eggs laid, if the humidity is increased. • Coconut rhinoceros beetle Oryctes rhinoceros devlopes dark chitin in moist air and light color chitin in dry air conditions.

RAINFALL: • Rainfall is closely related to humidity, and RH is dependent on rainfall. • The total amount of RF and its distribution in time influences the abundance of insects in a tract. • >12.5cm rain during summer (may-june) results in increase in soil moisture, which is not favourable to the cutworms, and hence are forced to come out of soil and fall a ready prey to their parasites and predators. On the other hand, if the rainfall is less than 10-12.5cm during summer, they remain protected in soil and there can be a pest outbreak in the next season. So the pest outbreak can be forecasted based on number of wet days during may-june, like if the number of wet days are <10, there will be an increase in cutworm in the following year. • Desert locust doesn’t lays eggs unless the soil has sufficient moisture, and further even if it lays eggs, the eggs will not hatch until the sufficient moisture is present in soil. Rainfall also plays an important role in movement of swarms of desert locust. • Saturated condition of the moisture is unfavourable for the development of cotton spotted boll worm Earias vitella . • Red pumpkin beetle Rhapidopalpa foveicollis (chrysomelidae-coleoptera) withholds eggs until it comes across moist soil. • Rain induces emergence of most of the insects from soil, while ants, termites, red hairy caterpillar, root grub betles etc. emerge out from soil after receipt of rains.

Lecture: 4 Light -phototaxis, photoperiodism-its effect on growth, moulting activity or behavior, oviposition and pigmentation, use of light as a factor of insect control; Atmospheric pressure – its effect on behaviors; Air currents - effect on dispersal of insects-edaphic factors-water currents.

LIGHT : • The sun is the chief source of radiant energy and light on earth. The rays in the light spectrum play an important role in the biological field. For instance, the basic process of food manufacture in nature is accomplished under the visible rays, especially the blue and red. Wavelengths of 400-760nm are in visible range, and all the shorter wavelengths of radiant energy up to and including visible range, which is measurable is considered as an ecological factor of light. • Different properties of light that influence the organisms are illumination, photoperiod, wavelength of light rays, their direction and degree of polarization. Intensity of light is measured in LUX, and luminosity is expressed quantitatively in terms on lumens. • The effect of light on the distribution and multiplication of animals is different from the effect of temperature and moisture, in that there is no lethal effect of low or higher levels of light. There are several species of insects which can live in total darkness or continuous light. Thus, for insects, there is no medium range of favourable light comparable with temperature and moisture. • The importance of light lies in relation to the behavior of insects and the token stimulus which it provides to enable them to regulate and synchronize their life-cycles with seasonal change. 1. Light & Insect movement: Light controls the locomotory activity of many lower organisms by direct action on their speed of locomotion. The higher activity under increased illumination is of great importance in the lives of many aquatic invertebrates and the smaller terrestrial forms, including insects. This undirected movement in relation to light is called photokinesis . 2. Light & Insect orientation: Phototaxis : Light also plays an important role in the orientation of animals through directed movements called phototaxis . The movement of an organism towards or away from source of light is called phototaxis. Phototaxis may be negative or positive. This behavior may serve to bring the animals to the right place at the right time. The phototactic reaction of animals to light can be modified or reversed by number of factors such as temperature, moisture, food and age. Green leaf hoppers of paddy Nephotettix virescens (cicadellidae:homoptera) attracts to light in hot humid conditions. Colorado potato beetles ( Leptinotarsa spp. ) are ordinarily attracted to light but are repelled when the conditions are dry. Insects which are active during day are called as diurnal, insects which are active during night called as noctuirnal, and others which are active during dusk are known as crepuscular. • For example, cockroaches are an example of a negatively phototactic organism , while moths are positively phototactic or phototactic , meaning they automatically move toward light. • In honeybees, there is a correlation between hours of sunshine and their activity. • Several Moths, leafhoppers, and beetles are known to be attracted to light at dusk and during night. Chafer beetles and many moths pass the day in concealment. Most of the moths are attracted to light and are known as photopositive or phototropic. This

behavior has been extensively used through light-traps for observing brood-emergence (Rice stem borer) and the population fluctuations of some insect pests. Light-traps of 17

different colours have been tried and found that most insects attracts to UV light more than other lights. Moths are more sensitive to some wavelengths of light-ultraviolet , for example- than they are to others. A white light will attract more moths than a yellow light. Yellow is a wavelength moths don't respond to. • Cockroaches hide during daytime. • Dusk (evening light) is most usual time for flight and copulation for moths. • Dusk is most usual time for emergence of winged white ants. • Grubs of Trogoderma spp. s how -ve reaction to light (photonegative). • Some insects are able to detect polarized light. The honeybee can perceive the degree of polarization of light in different regions of the sky and used this information in combination with other factors to determine the proper line of flight on a cloudy day. • Based on this principle, artificial light can be employed as a source for attracting of deterring insects, in IPM programs. The traps with light source for attracting various insects are known as light traps. 3. Light & response for light hours: Photoperiodism: The number of hours of light in a day length of 24 hours is termed as photoperiod, and the response of organisms to the photoperiod is known as photoperiodism . Based on the response to light hours, the insects are classified in to two types; short-day species, which likes short day lengths, and when exposed to long day lengths, they enter into inactive phase i.e. diapause ( Silkworm , Bombyx mori), long-day species, likes long day hours, and when exposed to shorter day lengths, they enter into inactive phase i.e diapause (cotton pink bollworm , Pectinophora gossypiella). • The motor activity rhythms of insects that are influenced by photoperiod include locomotion, feeding, adult emergence, mating and oviposition. The moulting and growth of some insects may be influenced by photoperiod. • The larvae of Plutella xylostella (diamond backed moth) reared in laboratory with 9hrs day light (all other parameters constant) completed the development in a longer period than those exposed to 15hrs day light. • The insect photoperiodic responses are known to control polymorphism characterized by the body form, pigmentation or the mode of reproduction. The winged and wingless forms of some aphids are produced due to the influence of photoperiod. In reduced photoperiod, sexual forms (winged forms) are produced in aphids. • Bean weevil ( Bruchus obtectus ) lays more eggs in total darkness than in light. • The fly of Dacus tryoni lays most of its eggs during the day, whereas the codling moth (Laspeyresia pomonella ) does so during the night. • The photoperiod plays a major role in the ecological adaptations and phonological synchronization of insects with their food sources. 4. Light & Growth, moulting and fecundity: • Mulberry silkworm, Bombyx mori develops faster in light than in darkness. • Grubs of khapra beetle, Trgoderma granarium develops rapidly in light than in dark. • Moths of spotted bollworm of cotton (Earias vitella ) and red hairy caterpillar (Amsacta albistriga ) lay most eggs during periods of darkness. • The bean weevil lays eggs during total darkness. • Light stimulates the oviposition in mantids and inhibits in Periplanata spp. 5. Light & Body Pigmentation: In dark areas, less pigmentation develops in insects,

while the light color develops in more light areas.

ATMOSPHERIC PRESSURE: • Generally of little importance. • Locusts show great excitement and abnormal activity about half an hour before the occurance of storm when the atmospheric pressure is low. • Drosophila melanogaster flies stop moving when put under vacuum.

AIR CURRENTS: • Air currents, especially the upper air being strong, carries many insects like aphids and scales to far-off places and is an important factor for dispersal of small insects.

Other parameters like concentration of oxygen, micro-environment also plays an important role in insect development either directly or indirectly.

EDAPHIC FACTORS: • Underlying the terrestrial ecosystem is a thin layer of the Earth’s crust or soil that provides habitats with a nutrient delivery, recycling and waste disposal system. • The abiotic factor soil is also called edaphic factor and such scientific study is called pedology or edaphology . • For plants, soil provides mechanical anchorage as well as water and minerals for nutrition, and for insects feeding on plant parts inside soil, stages of life cycle in soil, the soil factors play an important role for the developments and distribution of insect pest populations. • The nature of edaphic factors determines the nature of plant community which further influences the animal life forms; soil texture, soil air, soil PH, soil temperature, soil water etc. • Many basic and applied studies in insect ecology have considered responses of insect populations to their physical or chemical environment. For insects that live above ground, the mechanisms of behavioral responses to environmental factors often are directly observable. However, behavioral responses of soil-inhabiting insects are much more difficult to observe and quantify. Soil texture and structure can have a direct impact on arthropod behavior and adaptations. Field studies of soil insects often quantify the consequences of behavior, whereas the actual behaviors are only inferred. There have been studies of ecological and physiological adaptations of several soil arthropods that are not considered to be agricultural pests but have certain life history features that make them amenable to investigation. However, most insects that are agricultural pests as soil inhabiting immature forms (e.g., wireworms or rootworms in corn, scarab grubs) often have been studied in detail only in their more accessible, or observable, adult form. • Soil insects and other arthropods often move vertically in direct response to soil temperature, moving downward in late autumn to avoid freezing temperatures on the surface and returning to the surface in the spring to resume feeding. • Certain soil insects, such as the black vine and strawberry weevils and white grubs, are favored by coarse-textured soils. • Soil moisture is a major factor affecting the incidence, development, and control of pest problems. • The lengh of white grub their life cycle is affected by prevailing soil temperatures in different climatic zones. The larval life is prolonged if the soil moisture is high.

• As the insect grows, less of the soil pore space is available to the insect for free

movement, but it may take advantage of preexisting soil channels created by soil 19

macrofauna such as earthworms, other arthropods, or small vertebrates. Water-filled soil pores can inhibit movement. • Usually, eggs and pupae of insects are most resistant to soil moisture loss and least able to escape undesirable conditions. Larvae and adults are often mobile stages and may be able to move away or alter their behavior to minimize the impact of adverse moisture extremes. For example, scarab larvae can move downward in the soil profile to seek moister (and cooler) conditions during periods of heat or drought stress. Heavily sclerotized soil arthropods may be less vulnerable to cuticular moisture loss than are less sclerotized forms, such as grubs or maggots. • Legs of edaphic insects often are highly modified to facilitate digging or burrowing through soil. At least one leg segment is likely to be enlarged, specially shaped, and edged with spines or lobes to create functional spades. Expanded tibiae or femora provide increased surface area, providing improved leverage when the insect is moving soil. For example, mole crickets (Orthoptera: Gryllotalpidae) use their greatly enhanced fossorial forelegs to burrow through soils very rapidly. Notes:

Lecture: 5 Biotic factors-Food-classification of insects according to nutritional requirements-other organisms-inter and intra specific associations-beneficial and harmful associations of parasitoids based on site of attack, stage of attack, duration of attack, degree of parasitism and food habits.

BIOTIC FACTORS • Biotic components are the living things that shape an ecosystem . • A biotic factor is any living component that affects another organism, including animals that consume the organism in question, and the living food that the organism consumes. • Biotic factors include human influence. • Biotic components usually include: Producers , i.e. autotrophs: e.g. plants; they convert the energy (from the sun, or other sources such as hydrothermal vents) into food, Consumers , i.e. heterotrophs: e.g. animals, insects ; they depend upon producers for food, Decomposers , i.e. detritivores: e.g. fungi and bacteria; they break down chemicals from producers and consumers into simpler form which can be reused. • The following are biotic factors which affect the insect behavior, growth, dispersal, distribution and finally their population. 1. Food 2. Other organisms

FOOD: • Each insect species has certain natural food requirements for the completion of its life cycle. • Under normal conditions, there is happy adjustment between host and particular species of insects. But in the event of sudden increase in population, the density of population becomes too high to be supported by food availability in the area. Hence, competition for food as well as space will be there. • The quality and quantity of the food influences, survival, multiplication, growth and development and longevity of insect’s species.

Classification of insects based on food requirements:

Classification of insects based on food requirements

Om nivorous

Carnivorous

Herbivores

Polyphagous

Oligophagous

Monophagous

Saprophytes

Scavengers

Omnivorous insects Feed on both plants and Wasps and Cockroaches animals Carnivorous insects Feed on other animals, as Predatory Lady bird beetles, parasites and predators Mantids, Trichogramma spp. Bracon spp. Herbivores insects Feed on living plants Crop Insect Pests Polyphagous Feed on wide range of Locusts, Grasshoppers, Cutworms cultivated and wild plants (Spodoptera litura ), Borers (Helicoverpa armigera ) Oligophagous Feed on plants belong to Cabbage butterfly Pieris one family brassicae, Diamond backed moth Plutella xylostella Monophagous Feed on a single species of Paddy stem borer Scirpophaga plants incertulas, Brinjal epilachna beetle, Epilachna vegintioctopunctata Saprophytic insects Feed on decaying plants Fruit fly Drosophila , and cecidomyiid flies Scavengers Feed on dead organic House flies, Scarabaid beetles matter

OTHER ORGANISMS:

Other organisms

Intra -specific relations Inter -specific relations (Associations of individuals of the (Associations of individuals of same species) different species) Symbiosis

Beneficial Harmful Beneficial Harmful relations relations relations relations • Association of • Crowding, harmful due to • Commensalism • Parasites same sexes competition for food and space • Mutualism • Predators • Parental care • Disease outbreak • Association of • Cannibalism (Preying mantids, social insects and Red flour beetle Tribolium (Social- castaneum feed on their own Symbiosis) eggs, while Helicoverpa feed

their own larvae

Inter-Specific Associations: • Symbiosis : Inter-relations between organisms of different species which live in close and long-term union without harmful effects in known as symbiosis, and each member is known as symbiont . One insect feeds on the food collected by another insect of the same species eg: white ants, wasps, bees etc. Symbiotic relations may be categorized into mutulistic (useful), commensalitic (useful) and parasitic (harmful) relations. • Commensalism: One insect is benefitted by living on or inside of another insect without injuring the other is known as commensalism, and it usually uses lives on the waste or surplus food of its host. The benefitting insect is called commensal while the other one is called host. Eg. Gall-forming insects. When commensal uses its host as a means of transport, the phenomenon is termed as phoresy . Eg: blister beetles attach to legs and hairs of bees. Telenomus beneficiens (a parasite) attach themselves to the anal tuft hairs of rice stem borer females ( Scirpophaga incertulas ) for their transport, and this parasite parasitizes the freshly laid eggs. • Mutualism : When the association benefits both the symbionts, it is known as mutualism. Eg: Ants and Aphids, Termites and flagellate protozoans in their guts, Crow on cattle to pick up ticks and mites.

Harmful Associations: Parasites and predators are those that live at the expense of other living organisms.

Parasites : • Parasite is one, which attaches itself to the body of the other organism, either externally or internally, and gets nourishment and shelter, at least for shorter duration or for the entire life-cycle. • The organism which is attacked by the parasites is called host. • The phenomenon of obtaining nourishment at the expense of the host to which parasite is attached is called parasitism. Parasites can be grouped based on: Site of Parasitisation/attack Ecto- This attacks its host from outside of the body of the Head louse: Epiricania parasites host. The mother parasite lays its eggs on the body melanolenca, of the host and after the eggs are hatched, the larvae Epipyrops spp. on feed on the host by remaining outside only. sugarcane fly Endo- This enters the body of the host and feeds from Braconoids & parasites inside. The mother parasite either lays its eggs inside Ichnemonoids the tissues of the host or on the food materials of the Apanteles flavipes on host to gain entry inside jowar stem borer Stage of the Host Egg parasite Attacks egg stage of the host Trichogramma spp. Early larval parasite Attacks early larval stage Apanteles spp. Mid larval parasite Attacks mid larval stage Bracon hebetor Late larval parasite Attacks late larval stage Gonozus nephantidis Pre -pupal par asite Attacks pre -pupal stage Elasmus nephantidis Pupal parasite Attacks pupal stage Tetrastichus Israeli Trichospilus pupivora Stomatocerus spp.

Duration of the attack Transitory It is not a permanent parasite (completing all stages of its Braconoids and parasite life cycle on the same host), but transitory which spends Ichneumonoids few stages of its life cycle in one host and other stages on some other species of hosts, or as free living organism Permanent Which spends all the stages of its life cycles on the same Head louce Parasite host Degree of parasitisation Obligatory Parasite which can live only as a parasite and cannot Bird lice and parasite live away from the host even for short period Head louse Facultative Parasite, which can l ive away from the host at least Fleas parasite for shorter period Food Habits Monophagous Which has only one host spp and Gonizus nephantidis on (Host-Specific) cannot survive in another spp Opisina arenosella Oligophagous Which has very few hosts (more than Isotoma javensis on sugarcane one spp.) and hosts are closely related and sorghum borers Ployphagous Which has number of widely different Bracon spp. Apanteles Spp. host species on lepidopteran caterpillars

Lecture: 6 Concepts of balance of life-biotic potential & environmental resistance- normal coefficient of destruction-factors contributing to increase or decrease of population-causes for outbreak of pests in agro-ecosystem-explantation for causes (Intensive use of N fertilizers, Indiscriminate use of pesticides, Use of high yielding varieties and introduction of new crops, Destruction of forests and bringing forest area under cultivation, Monoculture, Introduction of a new pest in a new area, Accidental introduction of foreign pests, Destruction of natural enemies and Large scale storage of food grains).

CONCEPT OF BALANCE OF LIFE • The population of an insect or any organism may be defined as the number of individuals of particular species existing in a particular area at a time. • The population never remains constant for long, but tend to oscillate all the time about a theoretical optimum for the species. • Balance of Life or population balance or natural balance in nature is the maintenance of a more or less fluctuating population density of an organism, over a given period of time within certain definite upper and lower limits by the action of biotic and abiotic factors. • Several theories have been put forward to explain fluctuations in numbers and they differ widely; Nichloson’s Theory, Theory of Andrewwartha and Birtch, Milne’s Theory, Chitty’s Theory, Pimental’s Theory. • In their efforts to analyze the factors determining the population increase of a species, some ecologists have tried to calculate an animal’s maximum capacity (biotic potential) to increase in the absence of any environment. Chapman (1928) carriedout some lab experiments on the population increase of the flour beetles and gave the concept of biotic potential which he defined as the mean maximum rate of reproduction in a given period of time under given conditions . Later, Lotka, Birtch, Andrew wartha and Birth, mentioned another terminology, intrinsic rate of increase / the rate of natural increase / innate capacity for increase (rm), which can be defined as the maximal rate of increase attained at any particular combination of temperature, moisture, and quality of food and so on . Factors contributing to increase the insect population: • Any organism will multiply enormously if the environment is optimum. • Different organisms multiply at different rates. • Hence, it is well known that every organism has an inherent capacity to survive, reproduce and multiply in numbers. • The extent to which a species can multiply in a given period of time, if no adverse factors interfere is called its biotic potential , which is known as maximum reproductive power. • Chapman (1928) introduced this concept. • The biotic potential is the innate capacity to increase in populations , depends on: Biotic Potential (BP): p(fs) n, where p = Initial Population f = Fecundity s = Sex Ratio n = Number of generations/year or per given time or unit time

1. Initial Population (p): The more the initial population of an organism, the more its progeny. 2. Fecundity (f) : It is the average number of eggs laid by a female in its life. The more the fecundity, the more will be the resultant population. • A single moth of Earias vitella (bhendi fruit borer) lays about 200eggs/female, and completes life cycle in a month. If a pair of fruit borer adults is reared under most favourable conditions, after one month, 200 adults will come out (eg.100 males+100 females), and these can lay 20,000 eggs (200 eggs/female X 100 females). After 2 months, all these 20,000 adults can lay 2,000,000 eggs (200eggs/female X 10,000 females), and if you keep on calculating for one year, the number of adults of fruit borer would be 2,000,000,000,000,000,000,000,000. If a single moth can produce this much, and if all the adults are spread over earth like a blanket, they can cover 24.32 cms above earth surface. But, in reality, only a fraction of progeny completes life cycle due to environmental resistance . • Some insects like white ants reproduce very fast. • Mustard aphids have 40 generations/year. • A pair of housefly can produce from April-Aug to an extent of 191010X10 15 populations. Theoretically they can cover 14m deep layer on the earth. • A pair of Drosophila is allowed to produce; the progeny can cover the entire sub- continent and Burma. 3. Sex ratio (s) : It is the ratio of females to the total population and is represented by: Number of Females Sex Ratio (S) : Number of Males+Females 4. Number of generation per unit time (n) , or a year: Obviously, the greater the number of generations/year, the larger the population. • Mustard aphids (Lipaphis erysimi ) have over 40 generations a year. Factors tending to reduce the insect populations: • Full expression of the biotic potential of an organism is restricted by environmental resistance , any factor that inhibits the increase in number of the population. These factors include unfavourable climatic conditions; lack of space, light, or a suitable substrate; deficiencies of necessary chemical compounds or minerals; and the inhibiting effects of predators, parasites, disease organisms,... • In nature, powerful factors like abiotic and biotic working against the increase in insect populations. These biotic and abiotic factors are known as constituents of environmental resistance , which always tend to destroy a considerable proportion of insect life. The effect of physical and biological factors in preventing a species from reproducing at its maximum rate is called as environmental resistance. • The proportion of the population which is normally eliminated as a result of environmental resistance is known as normal coefficient of destruction , which can be expressed by the formula: Qn = 1 - (1/S) n/fn, where Q = coefficient of destruction n = number of generations per year or unit time s = sex ratio, when the population is taken as 1 f = fecundity

Balance of life • In nature, there are two sets of tendencies, namely biotic potential tendencies to increase the population, and the environmental resistance tending to reduce the population, hence the balance of life. • As such, there is a constant interaction between two opposing forces and they maintain dynamic equilibrium known as balance of life. • So, it is evident that in any case, the insects or other animals never attain the high density which they are potentially capable of doing. This is because of the environmental limiting factor like abiotic factors comprising mainly temperature and humidity, which at too high or too low levels adversely affect the insects. • Natural disturbances like heavy rain, hail storm, snow, sand storms, dust storms and very high wind velocity are adverse to insect itself. • Biotic factors like limitation of food, competition for food and space, and natural enemies act adversely and prevent the biotic potential being realized.

Causes for outbreaks of Pests in Agro-ecosystem • The unceasing struggle between man and his insect enemies started even before the dawn of civilization. In spite by the numerous advances made by man in evolving newer and deadlier weapons to fight the war against insects, he has not succeeded in eradicating even one of the thousands of serious pests which damages his food and other agricultural products, destroys his possessions and even attack himself and injure his domestic animals. • There generally exists an uneasy truce between the insect’s pests and man, and this is termed as ' balance in nature' . This balance is the result of two opposing phenomena, the 'biotic potential' ,i.e.,the tremendous capacity of insects to reproduce and multiply and the environment resistance which keeps their numbers under check. The environment resistance results in the death of adults before oviposition, in the mortality of eggs, larvae or pupae of the insects because of desiccation, starvation, parasites, predators, diseases and other adverse environmental conditions. Even any slight slakening of any of the processes of 'environment resistance' results in a population explosion of an insect species and the consequent epidemic. • The change in 'environment resistance' may take place owing to a number of causes, either natural or operated by different agencies. Man is perhaps the single most important agent, who has, from time to time, disturbed the 'balance of nature' and this has caused numerous pest problems and pest epidemics. The nature too, plays an important role in causing pest epidemics. Favourable conditions which reduce the natural mortality and bring down the rapid development of the insect coupled with the conditions unfavourable to the natural enemies of that insect, often result in the rapid increase of its population leading to a sudden pest out-break. Intensive cultivation practices and indiscriminate use of conventional as well as fourth generation pesticides like synthetic pyrethroids have created resistance among some of the key pests, including the American bollworm Helicoverpa armigera . Monocropping and favorable climatic conditions in certain years have further accentuated the problem. In the early1990s, the outbreak of cotton leaf virus reached epidemic proportions in the northern plains The reasons for this outbreak are not fully known, however based on the experience of other countries, it is reasonable to assume that excessive use and

abuse of pesticides is a major contributing factor . Dependence on chemicals has, in some cases, been so heavy that farmers have had to resort to a mix of several 27

pesticides, the so-called pesticide cocktails . And it is not uncommon to spray more than 30 times per season. Over-reliance on the use of synthetic pesticides in crop protection programs has resulted in disturbances to the environment, pest resurgence, pest resistance to pesticides, and lethal and sub-lethal effects on non-target organisms, including human’s world over . These side effects have raised public concern about the routine use and safety of pesticides. Therefore the farmers are required to manage their land with greater attention to direct and indirect off-farm impacts of various farming practices on water, soil, and wildlife resources. Thus, reducing dependence on chemical pesticides in favor of ecosystem manipulations is a better strategy for farmers of the region. Successful IPM is based on sound farmer’s knowledge of the on-going agro-ecological processes of the farming environment; such farmers should therefore be technically sound to make decisions on the most appropriate management strategies to apply at the specific period of crop development.

Causes for Pest Outbreaks 1. Intensive and Extensive Agriculture without proper crop changes: Monoculture (Intensive) leads to multiplication of pests and extensive cultivation of susceptible variety in larger areas lead to multiplication of the pest, due to non- competition for food. For example, stem borers in rice and sugar cane. In Andhra Pradesh, the number of attacks by aphids, thrips, jassids, etc. had risen since the introduction of Bt cotton in 2002. Tobacco leaf streak virus, tobacco caterpillars, etc have also emerged as new diseases and pests of Bt cotton. In 2007, reports of fungal root rot in Bt cotton were beginning to pour in from Warangal district in Andhra Pradesh. 2. Intensive use of Nitrogen fertilizers: Application of excessive nitrogenous fertilizers gives luxurious growth of the crop and makes it vulnerable to insect attack. For example, excessive nitrogen fertilizers application in rice & cotton lead to higher incidence of stem borer and sucking insects like aphids and leafhoppers, respectively, because there will be no competition for food. 3. Indiscriminate use of pesticides: Sometimes, use of pesticides as prophylactic or curative measure may result in: • Resistance, Resurgence, Residues, Secondary Pest incidences are the ill-effects. • Reducing one of the competing species of pests, while allowing others to multiply i.e. secondary infestation . • Continuous spraying of carbaryl on cotton against cotton bollworms, and on brinjal against fruit borer, resulted in mite infestation / outbreak. • Elimination of natural enemies of the pest sometimes leads to the pest outbreak. • Application of BHC in rice fields against BPH destroyed its natural enemies like mired bugs, spiders etc., over period of time, and led to the increase in the population of BHC later. • Similarly, indiscriminate use of synthetic pyrethroids on cotton resulted in outbreak of cotton whitefly in Guntur and prakasam districts during 1985.

4. Use of high yielding varieties and introduction of new crops: Mostly improved strains of crop plants are susceptible to pests. Sometimes the insects, which are considered as minor importance become pests of major importance with the introduction of new varieties or strains. • Improved strains of Cambodia cotton are susceptible to the spotted boll worm (Earias vitella) and the stem weevil (Pempherulus affinis) • The hybrid sorghum CSH-1 was severely attacked by stem fly (Atherigona varia soccata), stem borer (Chilo partellus) and earhead gallmidge (Contarinia sorghicola) • The rice variety RP 4-14 was subjected to severe attack by BPH (Nilaparvatha lugens) • Spread of the gallmidge resistant varities like Surekha and Kakatiya in Telangana region made the gallmidge incidence negligible, while other pests like BPH, stem borer (Scirpophaga incertulas) and whorl maggot (Hydrellia philippine) became serious pests of paddy in the region. • Growing of the Cabbage crop in the plains of Madurai district (TN) as a new crop for the area, resulted in wide spread incidence of green semilooper (Trichoplusia ni). 5. Destruction of forests and bringing forest area under cultivation: • Destruction of forest over wide areas for cultivation, affect several of the weather conditions viz., temperature, relative humidity, rain fall, wind velocity etc. in the locality and these conditions may be favourable for some insects, and develop enormously. • The insects feeding on the tress as pests on the forest trees are then driven to neighboring crop areas, where they may infest the cultivated crops and survive as new pests. 6. Destruction of natural enemies: • Due to excessive use of pesticides, natural enemies are being destroyed, and hence pest outbreaks because of natural imbalances. • Synthetic pyrethroids eliminated the natural enemies of white fly, and hence white fly outbreaks during 1985 in cotton crops of Guntur and Prakasam dist . 7. Improved agronomic practices: • Excessive use of Nitrogen fertilizers in rice lead to outbreaks of leaf folder in rice. • Similarly, closer planting in rice lead to outbreaks of leaf folder and BPH. • Application of granular insecticides possessing phytotonic effects led to luxurious crop growth favourable for hoppers, and other pests. 8. Introduction of new pests in new areas: • Pest multiplies fast in new area due to absence of its natural enemies, and hence pest outbreaks. • Apple wooly aphid Eriosoma lanigerum multiplied fast due to absence of its natural enemy Aphelinus mali . (Chalcid parasitoids introduced into kullu valley and later in many parts of India for the control of apple wooly aphid).

9. Accidental introduction of pests from foreign countries: Name of the Insect Pest Scientific Name Subabul psyllid Heteropsylla cubana American Serpentine leaf miner Liriomyza trifolii Coffee berry borer Hypothenemus hampei Spiralling white fly Aleurodicus disperses Coconut mite Aceria quadrasticus Diamond backed moth on cauliflower Plutella xylostella Potato tuber moth Phthormaea operculella Cottony cushiony scale -polyphagous Icerya purchase Wooly ap hid on Apple Eriosoma lanigerum Mealy bug in cotton -New Pen acoccus solenopsus San Jose Scale Quadraspidiotus perniciosus Potato-Golden cyst nematode Globodera rostochiensis Giant African Snail Achatina fulica The scientists conducted a survey at 47 locations in the nine cotton-growing states, and found only two mealy bug species infesting the cotton plants from all nine states: the solenopsis mealy bug, Penacoccus solenopsis , and the pink hibiscus mealy bug, Maconellicoccus hirsutus . However, P. solenopsis was the predominant species, comprising 95 percent of the samples examined. Furthermore, the scientists confirmed that P. solenopsis is a new exotic species to India originating in the US , where it was reported to damage cotton and other crops in 14 plant families. Mealy bugs (Hemiptera: Pseudococcidae) are small sap-sucking Insects, and some species cause severe economic damage to a wide range of vegetables, horticultural and field crops. Infested plants can exhibit general symptoms of distorted and bushy shoots, crinkled and/or twisted bunchy leaves, and stunted plants that may dry completely. Historically, mealy bugs were never considered major pests of cotton in India. There have been isolated reports of M. hirsutus on the native ‘desi’ species, Gossypium arboretum in Punjab and on the new world cotton Gossypium herbaceum in Gujarat. But no published evidence of mealy bugs on Gossypium hirsutum which currently occupies more than 80 percent of the cotton cultivated in the country. 10. Large scale storage of food grains: serve as reservoir for pest multiplication, and lead to outbreak. Urbanization, changes in ecological balance. Rats found in underground drainage in urban areas.

Lecture: 7 Pest Surveillance-definition-importance in IPM and its advantages-components of pest surveillance-pest forecasting-types of forecasting (long-term & short-term forecasting-their advantages)-insect pests-defintions of negligible, minor and major pests; different categories of pests-regular, occasional, seasonal, persistent, sporadic, epidemic and endemic pests with examples .

• Surveillance is the monitoring of the behavior, activities, or other changing information , usually of people, insects, and pathogens. It most usually refers to observation of individuals or groups by government organizations, but disease surveillance, for example, is monitoring the progress of a disease in a community. • The word surveillance comes from the French word for "watching over". • Pest Surveillance is the systematic monitoring of pest population, dispersion, and dynamics in different crop growth phases to forewarn the farmers to take up timely required crop protection measures . • Pest Surveillance is the constant watch on population dynamics of pest, its incidence and damage on each crop at fixed intervals, to fore-warn farmers to take-up timely crop protection measures. • Regular monitoring of the pest will aid in decision making of pest management practices, and this can be achieved through pest surveillance . • Pest surveillance can be done using the light traps, pheromone traps, food traps, attractants, pitfall traps (for soil insects), field scouting etc. Importance and advantages of Pest Surveillance: 1. Useful for pest forecasting 2. Help to plan cropping pattern 3. Help to plan pest management programmes 4. Aids in developing models, and to find-out the Thumb Rule Models. 5. Help in application of insecticides (stage, dose, type etc.) 6. Helps in maintaining stability of Agroecosystem. Components required for Pest Surveillance: 1. Identification of the Pest 2. Distribution pattern, and prevalence of the Pest 3. Severity of Pest 4. Levels of incidence of the pest 5. Losses due to pest incidence 6. Population dynamics 7. Weather parameters 8. Data on Natural enemies Pest surveillance: • Pest surveillance can be done using the light traps, pheromone traps, food traps, attractants, pitfall traps (for soil insects), field scouting etc . • Pest surveillance is usually done in two methods; fixed plot and row-plot surveillance. • Based on the surveillance, using various techniques, pest forecasting is done.

Forecasting: • Forecasting is the process of making statements about events whose actual outcomes (typically) have not yet been observed . A common place example might be estimation of the expected value for some variable of interest at some specified future date. Prediction is a similar, but more general term. Both might refer to formal statistical methods employing time series, cross-sectional or longitudinal data, or alternatively to less formal judgmental methods. • Pest forecasting is based on the models developed using the previous data points and many organizations are involved in forecasting of pest incidences and also fore- warning about the pest outbreaks. • Pest Forecasting is the systematic monitoring of pest population, dispersion and dynamics in different crop growth phases using models prepared based on the previous data, to forewarn the farmers to take-up timely crop protection measures needed. Advance knowledge of probable pest infestation (out breaks) in a crop would be very useful not only to plan the cropping pattern (to minimize the pest damage) but also to get the best advantage of pest management programs. • Pest Forecast will help and guide us with insect timing and biology to eliminate blanket applications of pesticide, reduce pesticide amounts, and achieve quality results . Online pest forecasting data is developed by both public and private sectors. (eg.: http://www.pestforecast.com). • Crop plant diseases and insect pests predict is the foundation of integrated control in advance, the important prerequisite of a bumper harvest as a result of effective control. However, such predict is affected not only by the characteristic of insect pests but also the restriction of the meteorological factor. Traditional forecasting methods, including data set fitting, regression and approximation theory and so on, are based on the data analysis and model construction manually. Now the new concept is GP (Genetic Programming) which has the characteristic of self-organization, self-learning and self- adaptation, to get the mathematics model from history data of insect pests for forecasting system. • Forecasting pest incidence often requires systematically recorded specific field data in an elaborate manner over considerable period of time which can be easily retrieved and analyzed. Insect Forecasting is useful in the following ways: • To predict the forth-coming infestation level of the pest , which knowledge is essential in justifying use of control measures mainly insecticidal applications? • To find-out the critical stage at which the applications of insecticides would afford maximum protection . • To assess the level of population and damage by pest during different growth stages of crops • To study the influence of weather and seasonal parameters on pest . • To fix-up hot-spots, endemic and epidemic areas of the pest . • To fore-warn farmers to make decisions in timing of control measures. Many diseases, insects, and weeds affect field crops every year. However, depending on weather conditions, the severity is very variable from year to year and very often control strategies are applied without considering this variability. With increasing concerns about production costs, food safety, and protection of the environment, appropriate timing of pesticide applications is required. For this purpose, economic thresholds should be understood thoroughly before the forecasting is propagated. 32

The forecasting of pest infestation must be related to the economic threshold levels of the pest, and can be done through: 1. Population studies : These studies should be carried-out several years using appropriate sampling methods to find out the seasonal range, the population variability and geographic distribution. The seasonal counts should be related to the climatic and topographical data. 2. Studies on the pest’s life history: The possible number of generations along with fecundity and the behavior of different larval instars under controlled conditions (either in insectary or laboratory) and field conditions can be related to range of environmental factors. 3. Field studies of the effects of climate on the pest and its environment: Climatic factors usually influence pest numbers either directly or indirectly. Systematic occurrence of insect pests and diseases in many places would contribute to evolving an effective pest forecasting module. For example, the spread of pest is largely influenced by wind currents. A nationwide pest observatory work over entire country is essential to note the systematic occurrence of insect pests in many places, and this would contribute to an effective pest forecasting service. The pest forecasting is based on monitoring of different weather parameters over a long period of time. Temperature, Relative humidity, and rainfall are the most commonly used weather parameters for insect pest forecasting, where the changes in these factors influence the type of pest as well as number of pests, followed by their extent of infestation. For example, increase in rainfall increases the incidence of cotton bollworm Helicoverpa armigera , castor red hairy caterpillar Amsacta albistriga, tobacco caterpillar Spodoptera litura and leaf spot diseases. Increase in temperature would lead to increase in the populations of sucking pests, mites and leaf minors. Areas where ‘critical’ infestations are likely to occur can also be forecast for some pests. The principal factors may be biotic, topographic or climatic. Combinations of temperature, rainfall, atmospheric humidity are most important. 4. Prediction from the empirical data on the pests of previous season: The pest population is forecasted based on the counts/occurrence of pest in the previous season. But this can be successful in case of static or regular pests. In the case of many others, the numbers of the pest in the early part of the cropping season will give an indication as to the extent of it likely multiplication with the progress of that season. • During 1941, a nationwide pest forecasting system was established in Japan. • Locust warning station in India was established in 1939. • The “Locust Control and Research“ is one of the divisions of the Directorate of Plant Protection, Quarantine and Storage, being implemented through an Organization known as Locust Warning Organization (LWO) established in 1939, to monitor, forewarn and control of Desert Locust (an international pest) with its 10 Circle Offices located at Bikaner, Jaisalmer, Barmer, Palanpur, Bhuj, Jalore, Phalodi, Nagaur, Suratgarh and Churu with its field Headquarters at Jodhpur and a Central Headquarter Faridabad . • Besides, there is one Field Station for Investigations on Locusts (FSIL) situated at Bikaner. To strengthen the locust monitoring and forecasting, a Remote Sensing Laboratory has also been set up to prepare vegetation maps based on satellite imageries for locust forecasting.

Types of Forecasting: • The forecasting are mainly two types based on the requirements; short-term forecasting and long-term forecasting . The former cover a particular season or one or two successive seasons only, and is usually done by using the insect traps, often such predictions can also be based on rate of emergence of the pest (observed in insectory). The long-term forecasting covers larger areas and is mainly dependent on the possible effects of weather on the insect abundance or by extrapolating the present population density (sometimes it may go erroneous as a small change in practice will upset the prediction) eg: Locust warning stations. • Since the infestation of a pest within a season is influenced to quite a large extent by the climatic factors, short term forecasts can be beneficial by involving weather parameters as crop conditioners. • For long term forecasting more basic understanding of population dynamics of pest is required. The available methods of pest forecast can be classified into following: a) Forecasting based on observations of environmental factors: The pest forecasting is based on monitoring of different weather parameters over a long period of time. Temperature, Relative humidity, and rainfall are the most commonly used weather parameters for insect pest forecasting, where the changes in these factors influence the type of pest as well as number of pests, followed by their extent of infestation. For example, increase in rainfall increases the incidence of cotton bollworm Helicoverpa armigera , castor red hairy caterpillar Amsacta albistriga, tobacco caterpillar Spodoptera litura and leaf spot diseases. Increase in temperature would lead to increase in the populations of sucking pests, mites and leaf minors. b) Forecasting based on observations of climatic area: Areas where ‘critical’ infestations are likely to occur can also be forecast for some pests. The principal factors may be biotic, topographic or climatic. Combinations of temperature, rainfall, atmospheric humidity are most important. c) Predictions from empirical observations: The pest population is forecasted based on the counts/occurrence of pest in the previous season. But this can be successful in case of static or regular pests. In the case of many others, the numbers of the pest in the early part of the cropping season will give an indication as to the extent of it likely multiplication with the progress of that season. Since the infestation of a pest within a season is influenced to quite a large extent by the climatic factors, short term forecasts can be beneficial by involving weather parameters as crop conditioners. For long term forecasting more basic understanding of population dynamics of pest is required.

INSECT PESTS: • Pest is defined as insect or other organisms that cause any damage to crops, stored produce or animal. • Pest is an organism that causes damage resulting in economic loss to a plant or animal . It can also be said that pest is a living organism that thrives at the expense of other living organism. • The expression of "Pest" is used very broadly to insects, other invertebrates like nematodes, mites, snails and slugs, etc., and vertebrates like rats, birds, jackals, etc., that cause damage to crops, stored products and animals. • An insect reaches the status of a pest when its number increases and inflicts significance damage. • Pest that cause less than 5% loss in yield, are said to be negligible. • Pest that cause 5-10% loss in yield, are minor pests. • Pest that cause more than 10% loss in yield, are major pests.

Different categories of insect pests are: Regular pests: Occur most frequently (regularly) in a crop and has close association with particular crop. Eg: Chilli Thrips, Brinjal Shoot & Fruit borer, Sugar Cane Borers. Occasional Pests: The pest has close association with a particular crop. They occur occasionally. Eg: Rice Case Worm, Paddy Flea Beetle. Seasonal Pests: Occur mostly during a particular part of the year, usually the incidence is governed by climatic conditions. Eg: Red Hairy Cater Pillar on Ground Nut during April-May, Rice Grass Hopper ( Oxya nitidula ) during June-July. Persistent Pests: Occur on a crop persistently. Eg: Scales and Mealy Bugs, Cockroaches. Sporadic Pests: Occasionally causing serious damage. Eg: Paddy leaf roller (Chephalocrocis medinalis), Sucking pests on Sorghum (aphids and shoot bug). Spodoptera litura on Cotton. Epidemic Pests: Epidemic, means abundance , outbreaks (sudden increase in large numbers) of a pest in a given area at given time. Endemic Pests: (Endemic, mean belonging, or native to, prevalent in a particular area). Endemic means a pest occurs continuously and with predictable regularity in a specific area or population. Native pest or pests permanantlay established in an area. Eg: Citrus black fly, endemic to Nagpur area, Black headed caterpillar (Opisina arenosella ) of Coconut is endemic in Coastal Tracts of Kerala, Paddy Gall Midge, Orseolia oryzae in Warangal tracts of AP. Exotice Pests: Non-Native or Non-Indeginous Pests not known to occur in the state or country. Notes:

Lecture: 8 Integrated pest management (IPM)-introduction-importance-evolution on IPM, collapse of control systems, patterns of crop protection and environmental contamination-concepts & principles of IPM-economic threshold level (ETL), economic injury level (EIL), general equilibrium position (GEP)-components/tools of IPM-practices, scope and limitations of IPM. Why Crop Protection: India with diversified agro-ecosystems responded spontaneously to the technologies of green revolution with introduction of several components in crop production like developing and adopting high yielding varieties, hybrids, usage of new agro-chemicals and adoption of intensive crop cultivation techniques. The gains of green revolution reflected in the shape of production of 200 million tonnes of food grains, 25 million tonnes of oil seeds and 15 million tonnes of fibres per annum. But these steady gains in agricultural production over past four decades have not fully overcome the problem of rising demand caused by soaring population growth. Adding to the population explosion, there were frequent setbacks to crop production experienced in the shape of abiotic and biotic stresses during the last two decades in several food crops where intensive farm practices were adopted. Among these stresses on major crops, increased pest populations leading to the stage of collapse of economy, at times keep the planners and executors to be helpless. In the past one and half decades, the periodical unabated explosions of aphids, whiteflies, bollworms, pod borers, defoliators, coccids, cutworms, plant hoppers etc., as direct crop damagers and disease transmitters in different regions of the country have made agriculture less remunerative and highly risk prone. The ability of some of these pests to develop resistance curbs the effectiveness of many commercial chemicals. Resistance has accelerated in many insect species and it was reported that more than 500 insect and mite species are immune to one or more insecticides at present . Similarly about 150 plant pathogens such as fungus and bacteria are now shielded against fungicides. Some of the weedicides also found effective earlier failed to control weeds now-a-days. Experts assessment reveal that around 22 per cent of yield losses in major crops like Rice, Cotton, Groundnut, Sugarcane, Sorghum, Tomato, Chillies, Mango, Grapes, etc., can be attributed to insect pests . Hence, there is need to reduce if not eliminate these losses by protecting the crops from different pests through appropriate techniques. At present day the role of crop protection in agriculture is of great importance and a challenging process than before, as the so called resistant species should be brought under check. All other management practices of crop husbandry will be futile if the crop is not protected against the ravages of pests. In absence of crop protection the yields may be drastically declined. The entire effort of growing a crop will be defeated in absence of crop protection resulting in financial loss to the grower. So the crop protection against various pests is a must in agriculture. Integrated Pest Management (IPM): Introduction, Importance and Evolution: • IPM is a system that in the context of the associated environment and the population dynamics of the pest species utilizes all suitable techniques and methods in as compatible manner as possible and maintains the pest populations at levels below those causing economic injury (FAO, 1972). In integrated pest management both crop and pest are seen as part of a dynamic agro-ecosystem. • Integrated Pest Management (IPM) is a broad ecological approach for managing pest problems encompassing available methods and techniques of pest control such as cultural, mechanical, biological and chemical in a compatible manner. The objectives of the IPM approach are to increase crop production with minimum input costs,

minimize environmental pollution and maintain ecological equilibrium (as described

by Directorate of Plant Protection, Quarantine & Storate, GOI, India) 36

• IPM is a decision support system for the selection and use of pest control tactics, singly or harmoniously coordinated into a management strategy, based on cost/benefit analyses that take into account the interests of and impacts on the producers, society and the environment . • Therefore, IPM is a multi-tactical maneuver as it often intertwines different tactics in a compatible manner to limit pest population up to desired level and it is also multifaceted as it concerns economy, ecology and safety to environment. This is expected that this system of pest population management will be sustained one. • IPM is an intelligent selection and use of appropriate pest-control actions that ensure favorable economic, environmental, and societal consequences. • IPM attempts to capitalize on natural biological factors that limit pest out breaks, only using chemicals as a last resort. The goal is to reduce crop damage to a level where it is economically tolerable; using control measures whose cost both economic and ecological is not excessive. A number of non-chemical cultural practices form the core of IPM. But IPM does not preclude chemical pesticide usage. Pesticide usage is one of weapons in the management armoury to us that can be exploited sensibly and judiciously. • Integrated Pest Management (IPM) is a decision-making process that supports a balanced approach to manage crop and livestock production systems. The goal is effective, economical and environmentally-sound suppression of pests . For the purposes of this document, pests include insects and mites, plant diseases, weeds, nematodes, and problem wildlife. • The objective of IPM is not to eradicate a pest but to reduce its abundance to levels that no longer pose an economic threat to plants and animals . • Integrated pest management is the best combination of different cultivation and pest control practices. • IPM is not an organic or non-pesticide approach to pest control. Organic producers also use IPM and certain approved pesticides to protect their crops and livestock. One of the main goals of IPM is to promote the use of effective, less toxic pesticides only if and when necessary. • Evolution of IPM is based on the experiences and threats faced since green revolution, broadly to reduce cost of cultuvation, environmental contamination, safe food production, and other related issues: Pre 1970; Economics, 1970-1990’s; Environment, 1990’s-2000; Food safety • The concept of IPM evolved in response to collapse of control systems, due to problems caused by an over-reliance on chemical pesticides . Excessive & indiscriminate use of insecticides in most cropping eocsystems, led to problems of: a) insecticide resistance (pest capabilties to avoid pesticide toxicities), b) elimination of natural enemies of pests (ecological imbalances, leading to secondary pest outbreaks, minor pest becomes major pest), c) outbreaks of formerly suppressed pests (primary pest resurgence), d) hazards to non-target species, and e) environmental and food contamination through accumulation of pesticide residues. This has prompted the necessity for the development of non-insecticidal alternatives that could be feasible and effective for insect pest management, while also being compatible with the environment. Hence, Integrated Pest Management approaches incorporate all approaches to ensure favourable ecological, economical and sociological consequences.

Insecticide Resistance: Pesticide resistance is the adaptation of pest population targeted by a pesticide resulting in decreased susceptibility to that chemical. In other words, pests develop a resistance to a chemical through natural selection: the most resistant organisms are the ones to survive and pass on their genetic traits to their offspring. In other words, insecticide resistance is 'a heritable change in the sensitivity of a pest population that is reflected in the repeated failure of a product to achieve the expected level of control when used according to the label recommendation for that pest species'. Pesticide resistance is increasing in occurrence. Over 500 species of pests have developed a resistance to a pesticide. Other sources estimate the number to be around 1000 species since 1945. Rachel Carson predicted the phenomenon in her 1962 book Silent Spring . The Resistance mechanism develops through, elimination of individuals that are susceptible to insecticides, and hence left with insecticide resistant individuals, which later reproduce giving origin to resistant offspring that when have offspring themselves produce resistance progeny. Thus, insecticide resistance is the result of the selection of insect strains tolerant to doses of insecticides that would kill the majority of the normal insect population . Insecticide resistance was recognized as a problem in 1911 when citrus scales acquired certain tolerance to insecticides. In the 1940’s resistance became a concern due mainly to the use of organochlorines. After the 1950s a lot of case studies of insecticide resistance began to accumulate. Insecticide Resistance-Current Status in India: A case study with cotton Resistance to pyrethriods continues to be high with levels of 108 to 7220 fold in almost all parts of the country. Pyrethroid resistance is wide spread in India, at high levels in Maharashtra, Punjab, AP and Tamilnadu Resistance levels during the entire season are usually high with minor exceptions during early season are usually high with minor exceptions during early cotton season and appear to be independent of the pyrethroid use pattern. The problem is still most severe in the coastal belt of AP. When used alone pyrethroids are no longer expected to be effective against Helicoverpa except on larvae less than second in star stage. However, resistance assays carried out against the pink bollworm and spotted bollworm indicated that these were still susceptible to pyrethroids. Pyrethroid resistance levels during 1993-99 have been high all over India. Resistance to Endosulfan was found to be 1-14 fold in the field populations tested. Resistance to quinalphos was found to be low to moderate at 1-29 fold. Resistance was higher in the coastal belt of Andhra Pradesh and some pockets of Central India. It was also observed that resistance levels to OPs and endosulfan increase in the season depending on the use of these compounds. Organophosphates such as quinalphos, chlorpyriphos and profenophos can be used during the peak reproductive phase of the crop. Resistance to methomyl was 1-22 fold, with higher levels in the coastal belt of Andhra Pradesh and some parts of Central India. Ecotoxicology: 99% of the insecticides that is most commonly applied do not reach their target insect and may potentially be affecting a non-target organism or polluting the environment. Non target organisms not only include other insects but also vertebrates such as wildlife and humans or domestic animals. For example we first realized DDT was a problem when egg shells from predatory birds were weakened by DDT. People noticed this in the UK in 1967. Insecticides can reach non-target habitats or ecosystems and affect non-target organisms within these non-targeted habitats. Pyrethroids for instance, affect fish. Carbamates for instance are very toxic to earthworms. Some organophosphates too. Earthworms provide important services for agriculture such as the aeration of the soil. Eliminating them or reducing their populations might affect the productivity of certain crops. Pest Resurgence: Resurgence is an abnormal increase in the pest population resulting in the insecticidal application , often far exceeding the economic injury level. Pest resurgence is the rapid reappearance of a pest population in injurious numbers, usually brought about after the application of a broad-spectrum pesticide has killed the natural enemies which normally keep a pest in check . A well- known example in rice cultivation is the resurgence of brown plant hopper (BPH). If no pesticides are used, BPH is kept under control by its natural enemies (mirid bugs, ladybird beetles, spiders and various pathogens). Pesticides kill the beneficials and create a situation where populations of BPH can multiply rapidly and thus become a man-made pest. Resurgence can be easily avoided by not spraying pesticides. But for many farmers it is difficult to recognize that resurgence has occurred in their field. They spray regularly because they see pests in their fields, without realizing that it is actually the spraying which is causing the pest problem. Another example is about spider mites . Spider mites are normally kept under control by populations of

predatory mites. If pesticides are used, the predatory mites get wiped out and the populations of spider mites can increase and become a problem. The farmer responds by spraying more (to control the spider

mites) while the proper response would be to stop spraying so that predatory mites can come back to 38

control the pest. Maximum cases of resurgence of insects belong to the orders Homopterous (44%) followed by phytophagous mites (26%) and Lepidoptarous (24%) pests. The first report of pest resurgence as induced by insecticides was by the red spider mite on cotton with usage of DDT in 1970 . Maximum reports of resurgence of insect pests are planthoppers especially brown plant hopper (BPH) of rice. BPH was a minor pest during 1950's but now it has become a major pest of rice due to extensive use of insecticides. The factors implicated in BPH resurgence include reduction of nymphal stage, longer oviposition period, shortened lifecycle, enhanced reproductive rate, higher feeding rate and destruction of natural enemies especially Cyrtorhinus lividipennis . Factors influencing pesticide-induced resurgence : a). Insecticide related : Insecticide rate, Insecticide type, Method of application, sublethal dosage of insecticides, Timing of insecticide application, Number of insecticide applications. b). Host-plant related : Nutritional status of the host plant, Resistance level of host plant, Influence of insecticide on insect life stage, altered biochemistry of host plant, c). Mortality of natural enemies, d). Reduction in competitive pest species, e). Stimulation of neurosecretory forces to enhance yolk formation and total fecundity f). Stimulation of feeding, digestion and assimilation of in the target pest. Secondary pest outbreak : After a period of time growers encounters difficulties in connection with the use of pesticides. Many pests started to show signs of resistance to the chemicals. As time went on it took more frequent spraying with heavier doses to control these pests. In some cases the pests became so resistant that they could no longer be successfully controlled by that particular pesticide. Next, growers started to see pests that they had never encountered before. This phenomenon was termed a secondary pest outbreak. An insect or mite that was previously at very low population levels now occurred in epidemic numbers because a pesticide used against another pest species killed the agents that kept this ‘secondary pest’ at low population levels. In India, whitefly ( Bemisia tabaci ) is never considered as primary pest, but due to indiscriminate use of insecticides, whitefly outbreaks are recorded on cotton during 1990s. Insecticide Residues: Pesticide residue is major problem in chlorinated and organophosphorus compounds they are not easily degraded. In Chlorinated hydrocarbon bio-magnification occurs i.e., pesticide residue goes to the soil then passes to H2O and through water it enters in the body of organisms or in food chain these molecules get accumulated in fats and therefore their concentration increases. Biomagnification has long term effect such as teratogenic (birth defect), carcinogenic effect particularly seen in birds whereby thickness of shell gets reduced. Sometimes lethal mutation also occurs.

Essential components of IPM: IPM is a long-term approach to managing pests by combining biological, cultural, and chemical tools in a way that minimizes economic, health and environmental risks. Farming is a long-term endeavor so we want to use management practices that are themselves long-term. By combining chemical, biological and cultural control techniques to manage a pest problem we develop a broad-based strategy that will still be successful even if one particular technique does not work. Based on our experience with chemical controls, we know that pest control decisions must take into account not only economic risks but effects on the environment and public health, too.

Five Essential Components of an IPM Program 1. Understanding the ecology and dynamics of the crop. It is important to gather all of the knowledge about the crop we are growing. Most, if not all, pest problems can be directly related to the condition of the crop. The more we know about the ecology of the crop, the better pest management decisions we can make. For example, it is well known that over-vigorous grape-vine can support larger leafhopper populations than vines of less vigor. Therefore, one way to keep leafhopper populations at acceptable levels is to be sure to avoid excess vine growth and to thin

out the leaves around the grape cluster when the grapes are very small. Fewer leaves results in fewer leafhoppers. An additional benefit is that of increased air circulation,

which reduces the likeliness of a condition known as bunch rot. 39

2. Understanding the ecology and dynamics of the pest(s) and their natural enemies. Accurate identification of pests, their natural enemies and damage, is essential to select the best pest management practice or pesticide for the pest/crop combination. It is illegal to use a registered pesticide on a crop or against a pest not listed on the pesticide label. Knowing what natural enemies are present and active in the crop will aid in selecting a pesticide that poses the least risk to them. It is not only important to know what pests are present but also to know in detail about their life cycles, what makes their populations change, whether any natural controls are present and what effects these may have on the pests. By knowing as much about the pest as possible we may find some weak point that we can exploit. 3. Instituting a monitoring program to assess levels of pests and beneficial insects. It is vitally important to constantly monitor the pest levels in the field. This is a crucial aspect of an IPM approach. By knowing how many pests are present we can make the best decision about how much damage they might cause to the crop. If natural enemies are present we also need to know how many there are because they may take care of the pest problem for us. Timely monitoring of pests and beneficial organisms, pest damage, and environmental conditions, gives information needed to decide if and when to apply a pest management approach for optimal effectiveness. Knowing what and when beneficial organisms are present is useful to time pesticide application to minimize impact on the beneficial organisms. Pest and disease development models use environmental (weather) information to determine what life stage(s) of a pest is present or if plants are at risk of disease infection. This information is useful in timing pest monitoring and management activities. 4. Establishing an economic threshold for each pest. Effective monitoring and using economic thresholds make up the of core any IPM program. Making control decisions based on pest or damage monitoring data, potential damage, cost of control methods, value of production, impact of other pests, beneficial organisms and the environment. Decide if the cost of the pest management programme / pesticide application is justified in terms of the value of the commodity protected. When making decisions, consider the Economic Injury Level (EIL) and of Economic Threshold Level (ETL) where available. The EIL is the pest population level when the loss caused by the pest is equal to the cost of control measures. The ETL is the pest population or damage level when control measures are applied to keep the pest population from reaching the EIL. Both the ETL and EIL values can change from year to year depending on the crop value and control costs. For some pests the ET is zero because of quarantine regulations imposed by governments or markets. 5. Considering available control strategies and determining the most appropriate ones. A wide range of control techniques is available for crop pests. They can be divided into 5 broad categories: chemical controls such as pesticides, cultural controls such as mowing and tilling, natural controls such as natural enemy releases, behavioral control such as the use of insect pheromones, and genetic control such as the use of resistant rootstocks. It is very important to choose the right control strategy based on the economic nature of the pest problem, the cost of the particular control strategy and the effects of this strategy on the environment and public health. Using a combination of control methods -Use a combination of host plant resistance, behavioural, biological, chemical, cultural, sanitary and mechanical methods to reduce pest populations to acceptable levels.

• Host Plant Resistance • Behavioural control applies to insects. It takes advantage of insect responses to colors (e.g. yellow traps), odours (e.g. attractant-baited traps, sex pheromone dispensers for mating disruption), and light (e.g. black light traps, insect electrocutors). • Biological control uses natural enemies to control pests. Examples of natural enemies (also called biocontrol or biological control agents) include predators (lady bugs and lacewings that feed on aphids), parasitic wasps and flies that attack caterpillars, nematodes that attack insects, insects that attack weeds, and diseases of insects (fungi, viruses) and weeds (fungi). Once established, biocontrol agents can often keep their hosts (pests) from becoming problems. If pesticide use is necessary, select products with no or little impact on biocontrol agents. This preserves their presence or allows the establishment of introduced biocontrol agents. • Cultural control relates to production practices that discourage the introduction, establishment and development of pest populations. It minimizes the need for pesticides. Examples include growing pest resistant crop varieties, using disease-free plant materials, crop rotation, and waste management, optimizing plant growth through proper use of plant nutrients, soil amendments, and sanitation. • Mechanical control uses barriers or devices such as window screens, rodent traps, netting, fly paper, horticulture cloth, and mulches to exclude or destroy pests. These practices can reduce the need for pesticides. • Chemical control uses pesticides to control pests. Often pesticides are used only when all other available control options have not kept pest populations below the ETL. New less toxic, more target-specific products (often referred to as reduced-risk pesticides) are replacing older broad- spectrum synthetic pesticides in order to reduce risks to food, environmental and human safety. However, these products on average cost more, and require more precise application timing and frequency. • Sanitary methods includes cleaning of field equipments, planting certified seed and quarantine measures so as to avoid the introduction of new pest into new area.

IPM is an ‘Approach’ and Changes with Time IPM is not a technique or a recipe, but rather an approach to solving pest problems. Particular techniques for pest management may vary from field to field, year to year, crop to crop, and grower to grower but the overall approach is always the same, using the 5 essential components of an IPM program. It is important to point out that an IPM program is not a cookbook approach. It would be nice if we could tackle a pest problem the same way every time but history has shown us that this will not work. An IPM program is never complete. The reason for this is that over time we learn more about our crop, our pests and their natural enemies, and refine our monitoring programs. We also improve our economic thresholds, and develop new control strategies. As we gain more knowledge, we need to use it to refine our IPM programs to make them more effective and to ensure they will work in the long- term. This is the best way to minimize the economic impacts of pests in our fields and minimize the risks to our health and the environment.

Concept of Threshold Levels: Economic Threshold Level (ETL) : • Pest density at which control measures should be applied to prevent an increasing pest population from reaching the economic injury level. Economic Injury Level (EIL) : • Pest population density that produces incremental damage equal to the cost of preventing the damage. • The lowest population density that will cause economic damage . General Equilibrium Position (GEP) : • Average pest population density over a long period of time, unaffected by the temporary interventions of pest control.

Economic Thresholds Factors affecting Thresholds Pest Characteristics (Direct vs indirect pest)

EIL Feeding behavior ETL Ability to accurately sample pest

GEP Value of crop (High vs low value crop)

Pest density Pest Market price fluctuations Crop health Other pests, water, nutrition Time

Major Pest Minor Pest

EIL EIL ETL ETL

GEP Pest density Pest Pest density Pest

GEP

Time Time

Benefits of IPM: • Decreased use of pesticides • Protects environment through elimination of unnecessary pesticide applications. • Improves profitability • Reduces risk of crop losses by pest • Reduced risk of pesticides • Slower development of Insecticide resistance • Reduced risk to spray operators • Natural enemies are conserved • Increases the effectiveness of pest management practice through timely application • Healthier plants, safe food production • Saves time and money, and hence Peace of mind Limitations of IPM: • More complex, and requires higher degree of management • Requires comprehensive knowledge and expertise of the pest and pesticide products, as well as knowledge of environmental factors and conditions. • More labor intensive • Success can be weather dependent No Disadvantages are known, but only some limitations. Research organization involved in IPM programmes / research / planning: • NCIPM: National Centre for Integrated Pest Management (IARI campus, New Delhi) National Centre for Integrated Pest Management (NCIPM), a national research centre of Indian Council of Agricultural Research (ICAR), India was established in February, 1988 to cater to the emerging plant protection needs of different agro-ecological zones of the country. The activities of the centre extend across and beyond different disciplines and agencies to establish partnerships with SAU's, Government Agencies, Industries, NGOs and Farmers. NCIPM plans and conducts eco-friendly IPM research and development programmes, essentially required for sustainable agriculture. • CIPMC: Central Integrated Pest Management Centres (under DPPQS, located at various places in India); GOI formed 32 CIPMC in 28 states in 1992 with a mandate of these Centres is pest/disease monitoring, production and releases of biocontrol agents, conservation of biocontrol agents and Human Resource Development in IPM by imparting training to Agricultural Extension Officers

and farmers at the grassroots levels by organizing of Farmers' Field Schools (FFSs) in the farmers’ fields.

Lecture: 9 Host plant resistance-principles of host plant resistance-ecological resistance-phonological asynchrony, induced resistance & escape-genetic resistance-mono, oligo and polygenic resistance, major (vertical-specific-qualitative) or minor (horizontal-non-specific-quantitative) gene resistance-host plant selection process-host habitat finding, host finding, host recognition-host acceptance & host suitability-mechanisms of genetic resistance-antixenosis, non-preferences (antexenosis), antibiosis and tolerance-transgenic plants.

Host Plant Selection Process: Any agro ecosystem is a highly dynamic entity. It consists of different life forms from the single celled microorganisms to higher plants and animals. All life forms should mutually interact with each other in order to exchange energy and matter efficiently. So competition may occur among different organisms, end result of which will form a basis for their survival. Among this, the relationship between insects and their host plants will have an important role. Herbivorous insects will select their host plants based on their quality. Components of host plant quality (such as carbon, nitrogen, and defensive metabolites) directly affect potential and achieved herbivore life cycle. The responses of insect herbivores to changes in host plant quality vary within and between feeding guilds. Host-plant selection by phytophagous insects is largely determined by adult insects choosing the developmental location of offspring. However, immature stages themselves determine movements between different plant parts such as, roots or shoots or tender or mature parts, as also movements between adjacent plants. The relationship between insects and plants is a dynamic one, which may favor either the insect or the plant. The plant may discourage the insect's attention by various defense strategies or, sometimes it may also encourage visitations by insects.

Host plant selection is the process by which an insect detects a resource furnishing plant, within an environment of a magnitude of diversified plant species. Insect herbivores have been classified as monophagous (single host), oligophagous (few limited hosts) or polyphagous (many hosts) based on their host specificity. The host plant selection process in phytophagous insects is usually analysed as a chain of events (plant stimuli-insect responses) succeeding each other in time and space.

Generally, five phases are described (Kogan, 1994) in Host Plant Selection process by insects: Host Habitat finding Host finding Host recognition Host acceptance Host suitability

Host-Habitat Finding: The first phase of foraging by phytophagous insects is host habitat finding. The dispersing adult populations have to travel a distance towards a general host habitat using mechanisms that include anemotaxis, phototaxis, geotaxis and probably temperature and humidity preference. These mechanisms have important ecological implications and are of interest in pest management, but they have little effect on plant resistance. Normally most of the agricultural pests stay within the general area where crops are planted and hence this phase becomes less important in host selection. Host Finding: After passing through the dispersal or migratory phase, the phytophagous insects are behaviourally and physiologically tuned towards the next spectrum of foraging behavior. The process of finding is a purposeful search involving behavior that enables the finder to establish and maintain proximity with its desired habitat and consequently locate its appropriate host. Long range sensorial mechanisms, probably visual and olfactory bring the insect to close contact with the plant. The characteristic spectrum of green plants is in the green-yellow-orange region and this has its

counterpart in the maximal sensitivity of the insect visual pigments which is in the region of 500-580 nm. Several aphid & whitefly species tend to alight on green or yellow surfaces and larvae of certain

beetles are attracted towards vertical patterns. Mobile insects characteristically fly 43

upwind (positive anemotaxis) toward plant sources of volatile attractants. Thus grasshoppers and Colorado potato beetle tend to fly upwind increasing the chances of locating the host. Highly polyphagous insects such as migratory locust are attracted to patches of vegetation largely by visual stimuli. However, chemosensory inputs from the characteristic emanations of the green volatiles of ‘growing plants’ are important in specific host finding. Host Recognition: Host recognition is facilitated by specific volatiles, and oviposition is characteristically triggered by a combination of olfactory and gustatory inputs. Thus, the female apple maggot fly is attracted to maturing apple fruits through a combination of visual imaging of orange-red, fruit-sized spheres together with the emanation of butyl hexanoate and related volatiles from apple fruits. The onion maggot fly, Delia antique, is attracted to its host plant by the characteristic odor of propyl disulfide. The cabbage maggot fly, Delia brassicae, is drawn to allyl isothiocyanate liberated from the glucosinolates characteristic of the crucifers. Host Acceptance: Host acceptance is usually determined by test biting or by ovipositional probing. In the host acceptance process, insect feeding behavior undergoes three phases such as initiation, continuation and cessation of feeding at the point of satiation. The presence of phagostimulants is one of the important mechanism in promoting continuous feeding by the larve of silk worm, Bombyx mori on Morus spp., in response to morin: by larvae of Catalpa sphinx, Ceratomia catalpa, in response to catalposide in leaves of Catalpa spp., and by Chrysolina spp., beetles that feed on Hypericum spp. Host Suitability: It is determined by the nutritional value of the plant in terms of sugars, amino acids, lipids, proteins and vitamins and by the absence of deleterious factors such as toxic compounds. These determine the adequacy of food to sustain the various physiological processes related to the growth and development of larvae, and longevity and fecundity of adults. Consideration of all these factors suggests that true polyphagy is found occasionally, as with migratory locusts and army worms that devour almost any green vegetation, although there are marked preferences for different insects. Influence of Plant Chemiclas on Insects: Plant chemicals which affect behaviour have also been classified into two main groups. There are those which the insect can utilize as nutrients as well as behavioural cues, and then there are those which have no apparent nutrient value but which serve only as sign stimuli, enabling the insect to select the appropriate food or host-plant. These are known as secondary plant chemicals. Plant odours can attract or repel insects. In either case the volatile plant constituent affects the orientation of the insect with respect to the plant. It may influence larval or adult orientation or both. e.g. 3rd instar grass grubs are strongly attracted by the odour of fresh ryegrass root and that the odour of some legumes is even more attractive but the exact root volatiles involved was not identified

Host Plant Resistance (HPR): • Relative amount of heritable qualities possessed by the plants which influence the ultimate degree of damage done by insects is known as resistance of plants to insect pests (Painter 1951). • Insect Resistance comprises the heritable qualities of a plant that enables it to reduce the degree of insect damage it suffers (Painter 1951). • Resistance is also expressed by the relative damage to host plant in comparision to the susceptible host plant (Painter 1968). • Plant defense against herbivory or host-plant resistance (HPR) describes a range of adaptations evolved by plants which improve their survival and reproduction by reducing the impact of herbivores . • Plants use several strategies to defend against damage caused by herbivores. • Cultivars differ in their degree of resistance: extreme resistance to extreme susceptibility; low, moderate, and high.

Mechanisms of Resistence: • These can be two types; ecological resistance and genetic resistance , where the first one controlled by environment, and the latter controlled by genetic factors.

Host Plant Resistance

Ecological Resistance Genetic Resistance (Apparent Resistance) (True Resistance) (Non -Heritable) (Heritable)

Phenological Mode of Synchrony inheritance (Host evasion)

Induced Monogenic Oligogenic Polygenic Resistance

Escape Mode of Action / Ba sed on Mechanism

Non -Preference Anti-Biosis Tolerence (Antixenosis)

ECOLOGICAL RESISTANCE: • Ecological resistance refers to the biotic and abiotic factors in a recipient ecosystem that limit the population growth of an invading species. • This is also called as apparent resistance • Non-heritable • Although there is interest in applying this concept to the management and restoration of habitats influenced by damaging, invasive species, practical difficulties in restoring resistance have inhibited its broad-scale incorporation. Also, some ecologists have argued that resistance is unimportant in generating landscape pattern casting doubt on its potential usefulness in large-scale management. Despite temporal and spatial fluctuations in resistance being the norm, the concept provides a valuable foundation for a more sustainable approach to long-term pest management. 1). Phenological Synchrony (Host evasion): • The host plant passes through the susceptible stage quickly when insect populations are low. A crop which is in the field when the insect populations are low or matures before the insect populations reaches to high level (damaging levels) shows host evasion. A larva that requires fruiting structures for normal growth may starve to death on the leaves of the same host plant. Hence, asynchrony between the stage of the crop and the stage of the insect lead to escape of the host plant from insect damage. • In some crops, it is possible to create discontinuity in the pest's food supply simply by altering the time of planting or harvesting . This strategy, often known as phenological asynchrony , allows farmers to manage their crop so it remains " out of phase " with pest populations. 46

• Sweet corn, for example, can escape most injury from corn earworms ( Helicoverpa zea ) if it is planted in early spring and harvested before larvae mature. This asynchrony may be created by the early or late planting of the crop or certain varieties of the crop, depending on the pest nature and also depending on the endemic or epidemic nature of the pest. • Early planted rice crop escapes gall midge damage. This mechanism called as Psuedo-resistance as described by Painter, since the plants evade or escape the pest attack due to changes in environment and other factors, may be susceptible to the pest if occurs at right time and right stage of the crop. • Early planting in kharif and late planting in rabi minimizes the pest infestation on paddy stem borer ( Scirpophaga incertulas ). • Early sowing of redgram escapes the pod-fly (Melanagromyza obtuse) damage. • Delaying sunhemp sowing till the onset of south-west monsoon avoids sunhemp hairy caterpillar attack. • Careful timing of harvest dates in alfalfa can cause high mortality in populations of alfalfa weevil ( Hypera postica ) and alfalfa caterpillar ( Colias eurytheme ) by removing edible foliage before the larvae have completed development. • Harvest timing is often the most practical method available to foresters for controlling bark beetle (Scolytidae) infestations in pine plantations. 2). Induced resistance: • Changes in plants following damage or stress or are called induced responces , and these changes can increase the resistance to herbivore attack by reducing the preference for. • Some environmental conditions, like soil fertility and disease infections, temporarilty increase the level of resistance of the host plant species, by altering the physiology of the host plant. • Normal cultural practices such as fertilization and irrigation may cause drastic qualitative and quantitative changes in the host plant, and hence the response of the host plant varies to the pest attack or vice-versa. • Phytophagous insects are very sensitive to nutritional changes in the host plant. These changes results from fertilizers, absorbed through roots. Similarly, foliar application of some mineral nutrients and even certain insecticides has also been shown to influence the nutritional value of the host plants. • Regular rainfall (or overhead irrigation) can significantly reduce infestations of two spotted spider mites ( Tetranychus urticae ) in tree fruits. • For paddy cutworms, paddy swarming caters pillars, ragi cutworms, flooding the fields float these caterpillars leaving the plants. • Good irrigation keeps plants healthy, vigorous, and more resistant to insect injury. • Draining the paddy fields can reduce BPH populations, and also paddy caseworm which travel one plant to other through water. • It is not unusual for small amounts of injury to actually stimulate compensatory growth in healthy plants. • At high nitrogen, insects usually respond with an increase in survival and faster rate of development. • High nitrogen favour survival of aphids, while potash influence negatively. • Over dose of nitrogen application leads to stem borer attack in paddy, sucking pests in

cotton, chilli etc. • Root weevil attack in rice can minimized through application on 20kg ammonium

phosphate and 40kg super phosphate/ha. 47

• Many plants react to disease infections by producing and concentrating phenolic compounds such as phytoalexins (which offer resistance against disease by killing tissues around infected zone). 3). Escape: • A particular host plant is neither infested nor injured despite of local presence of insect pest. • Leaving gaps-Alley Ways of 0.5m for every 5m width in paddy fields increases the aeration and light, and BPH (Brown Plant Hopper-Nilaparvatha lugens ) incidence come down under highly aerated conditions. • Trash mulching / earthing up at month after planting of sugarcane reduces early stem borer (Chilo infuscatellus) attack in sugar cane. • Trap crops : Pests are strongly attracted to certain plants. When these plants are sown in the main field or along the borders, the pests gather on them. Raising trap crops as inter and/or border crops is an important cropping system approach. The trap crop distinctly attractive to the pest when compared to the main crop. It provides protection either by preventing the pest from reaching the main crop or by restricting them to a certain part of the field where they can be economically destroyed. Generally, these trap crops are planted on the borders of main crop. Mustard along with cabbage is a trap crop for the control of the Diamond Back Moth , aphids and the Leaf Webber. African marigold @ 100 plants/acre, in cotton / chilli / tomato is a good trap crop for the Helicoverpa armigera, besides it also attracts the adults of the leaf minor which lay eggs on its leaves. Similarly, planting Hibiscus @ 100 plants / acre in cotton also attracts insect pests. Castor is a good trap crop for tobacco cater pillar (Spodoptera litura ) in chilli / cotton/ tomato etc. Maize plants can be a trap crop to attract fruit fly adults in vegetable cultivation where the fruit fly (Bactrocera cucurbiate ) is a major problem. Tomato is a good trap crop in citrus for fruit sucking moths (Othereis materna ) • Intercropping (also known as mixed cropping ) is another way to reduce pest populations by increasing environmental diversity. In some cases, intercropping lowers the overall attractiveness of the environment, as when host and non-host plants are mixed together in a single planting . But in other cases, intercropping may concentrate the pest in a smaller, more manageable area so it can be controlled by some other tactic. Inter-cropping Cowpea with Sorghum can attract polyphagous insect pests on to sorghum which is leass value crop. Cotton system is ideally suitable for intercropping because of the relatively longer duration and its slow growth in the initial stages. The common practice of cotton cultivation is inter or mixed cropping with pulses which reduces the sucking pest complex on cotton. Similarly, planting of few rows of sorghum or maize in cotton reduces insect pest population due to disturbance of host selection process of insects. Intercropping of Pigeonpea in Sunflower crop @ 1:2 reduces Bihar Hairy Ceterpillar Spilosoma oblique attack.

GENETIC RESISTANCE:

Resistance based on Mode of Inheritance: Classification based on the number of genes responsible for the insect resistance mechanism. Monogenic resistance Oligogenic resistance Polygenic resistance Governed by single gene Governed by few genes Governed by many genes No intermediates, the The resistance among The resistance among population either populations may range populations may range from resistance or susceptible from low to high low to high Called as specific resistance Called as partial resistance Called as partial resistance Qualitative resistance Quantitative resistance Quantitative resistance Resistant characters are Resistant characters are variable, and influenced by stable over a wide range environmental conditions, and hence sometimes termed as of conditions environmental resistance. Sometimes the characters are also influenced by host nutritional conditions - Repeated selections through breeding in a crop result in accumulation of more genes for resistance in new varieties, which is the case in most of the varieties of crop plants Monogenic rice cultivars Digenic cultivars with Polygenic cultivars with may with genes wbph1, wbph2, genes wbph1+wbph2, genes for resistance to WBPH wbph3, wbph4, and wbph1+wbph3 for Sogotella furcifera wbph5 for resistance to resistance to WBPH WBPH Sogotella furcifera Sogotella furcifera

Vertical and Horizontal resistance: Varieties usually have one of these two types of resistance:

Vertical resistance Horizontal resistance Specific Non-specific Quantitative, Means it is either present or Qualitative, Means it can occur at any absent, there are no intermediates level, between a minimum and maximum Degree of resistance depends on one Degree of resistance depends on number of major gene minor genes Single gene resistance Multiple gene or Many gene resistance Its definitive characteristic is that it Its definitive characteristic is that it does involve gene-for-gene relationship not involve gene-for-gene relationship Effective against single or certain specific Effective against all known types of biotypes or insect pests, but not all biotypes Frequency distribution of resistance and Frequency distribution of resistance and susceptible plants in a population is susceptible plants in a population is discontinuous continuous

Resistance based on Mechanisms: Mechanisms of Genetic resistance have been grouped in to three cetegories by Painter (1951). Nonpreference or Antixenosis and Antibiosis refers to the response of the insect to the plant; tolerance refers to the response of the plant to the insect. (1) Nonpreference or Antixenosis: • Non-preferred plants lack the characteristics of the hosts for insect feeding, oviposition and shelter. Non-preference pertains to the insect rather than the host plant, and is not parallel to antibiosis. • Kogan and Ortman (1978) proposed the term Antoxenosis for nonpreference. • Antixenosis (against the guest) means the plant is considered to be a bad host. • The nonpreference may be due to morphological factors or chemical factors in bad hosts. (a) Morphological Antixenosis or Nonpreference: Some morphological structural plant features stop or prevent the normal feeding or oviposition by the herbivore. For example: Leaf hoppers unable to establish on plants with epidermis covered with thick layer of long cellulose hairs . Similarly, presence of trichomes, and hard woody stems contribute resistance to plants. (b) Chemical Antixenosis or Nonpreference: When two or more alternative foods are offered for phytophagous insects, they usually show a consistence pattern of preference or nonpreference. In adequate hosts are totally rejected, and some species starve to death on a diet that lack proper stimuli. Usually feeding preference of immature forms and oviposition preferences of adult forms coincides, but not always. For example: Ratna and TKM6 are resistant to paddy stem borer due to presence of high silica content which is not preferred for feeding . (2) Antibiosis: • Antibiosis means, adverse effects on the biology (survival, development and reproduction) of the insect. • Adverse physiological effects of a temporary or permanent nature resulting from the ingestion (with some chemicals) of plant by insect. The possible explanations for the effects on insects are due to: Presence of toxic metabolites (alkaloids, glucosides, quinones) Absence or insufficiency of essential nutrients Unbalanced proposition of nutrients Presence of anti-metabolites that render some essential nutrients unavailable Presence of enzymes that inhibit normal process of food digestion, and consequently utilization of nutrients. Presence of chemicals that inhibit physiological processes. • Insects show following symptoms when they feed on resistant variety antibiotic properties: Death of larva Abnormal growth rate Abnormal conversion of sor digested food Failure to pupate Failure to emerge adults from pupa Malformed pupa Malformed adults

Decrased fecundity Reduced fertility 50

Failure to concentrate food reserves followed by unsuccessful hibernation Restlessness and other irregular behavior • Young females of BPH feeding on Mudgo (rice variety) had under developed ovaries and contained few matured eggs. This is due to reduced asparagine content of resistance rice. • Very young corn (maize) plants are highly resistant to European corn borer Heliothis zea establishment and survival. This is due to high concentration of DIMBOA (a glycoside) [2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one] • Transgenic cultivars having delta-endotoxin shows Anti-biosis type of insect resistance against target insect pests. (3) Tolerance: • A tolerant plant can produce good yield even while it supports and insect population that would severely damage and decrease the yield of a non-tolerent plant. • It is the capacity of certain plants to repair injury or grow to produce an adequate yield despite supporting an insect population at a level capable of damaging a more susceptible host. • Tolerance results from one or more of the following factors: General vigour of the plants Regrowth of damaged tissues Strength of stems and resistance to lodging Production of additional branches Utilization of non-vital plant parts by an insect Lateral compensation by neighboring plants

Transgenic Plants: • Genetically modified plants are plants whose DNA is modified using genetic engineering techniques. In most cases the aim is to introduce a new trait to the plant which does not occur naturally in this species. Examples include resistance to certain pests, diseases or environmental conditions, or the production of a certain nutrient or pharmaceutical agent. • A transgenic crop plant contains a gene or genes which have been artificially inserted instead of the plant acquiring them through pollination. The inserted gene sequence (known as the transgene ) may come from another unrelated plant, or from a completely different species: transgenic Bt corn, for example, which produces its own insecticide, contains a gene from a bacterium. Plants containing transgenes are often called genetically modified or GM crops , although in reality all crops have been genetically modified from their original wild state by domestication, selection and controlled breeding over long periods of time. • The first field trials of genetically engineered plants occurred in France and the USA in 1986 when tobacco plants were engineered to be resistant to herbicides. In 1987 Plant Genetic Systems, was the (Belgium based) first company to develop genetically engineered (tobacco) plants with insect tolerance by expressing genes encoding for insecticidal proteins from Bacillus thuringiensis (Bt). • Bacillus thuringiensis or Bt is a naturally occurring soil bacterium used by farmers to control Lepidopteran insects because of a toxin it produces. Through genetic engineering, scientists have introduced the gene responsible for making the toxin into a range of crops, including cotton. Bt expresses the qualities of the insecticidal gene throughout the growing cycle of the plant. Cotton crops are very susceptible to pest 51

attacks and use up more than 10% of the world's pesticides and over 25% of insecticides. • Given the high chemical dependence of the cotton crop, cotton was one of the first crops to be genetically engineered by the US-based agrochemical multinational Monsanto, whose transgenic Bollgard (Bt) cottonseed varieties were a big draw among farmers the world over. Bt cotton, with its promise of reduced insecticide use and resistance to pest attacks - leading consequently to a rise in yields with lower costs - is being pushed by the multinational as an environmentally safe and cost-effective alternative to conventional cotton seeds. • But the Bt toxin targets only the bollworm complex, comprising the American bollworm, the Spotted bollworm, the Spiny bollworm and the Pink Bollworm. The Bt toxin Cry1Ac, approved for commercialisation, is particularly specific to American Bollworm, which attacks the plant after 60 days of sowing. The Pink bollworm attacks the plant after 130 days of sowing - the time of the first pick. While Cry1Ac has only a moderate effect on the Pink bollworm, none of the Mahyco hybrids has any impact on pests such as Thrips, Aphids and Jassids, which attack the plant during its early phase. Thus, while the number of sprays against the bollworm could come down, there may not be a reduction in the use of pesticides against the other pests. • India made its entry into commercial agricultural biotechnology in March 2002 with the approval of three Bt-cotton hybrids for commercial cultivation, and these were marketed by Mahyco-Monsanto Biotech Limited (MMB), a joint venture of Mahyco and Monsanto. Realizing the potential of Bt-cotton, more Indian seed companies have shown interest in this technology and by 2010-end about 26 companies have become sub-licensees of MMB. • In 2002, bt cotton area in India is 72,000 acres (0.3% of total cotton area), by 2007, more than 66% of cotton area is with Bt cotton, and now almost all the cotton area issown with Bt cotton. • Bt cotton companies involved in Bt crops production based on Cry 1Ac gene. Mahyco Seeds Ltd Tulasi Seeds Pro Agro Seeds Rasi Seeds Krishidhan Seeds Bio -Seed Nuziveedu Seeds Ajeet Seeds Bayer Bioscience Ankur Seeds Nath Seeds Prabhat Agro Ganga Kaveri Seeds

Lecture: 10 Importance and history crop losses due to pests-plant protection measures in India-methods of pest control-natural and applied (preventive & curative methods)-cultural, mechanical, physical, legislative, biological and chemical methods.

Crop losses due to Insect Pests: • It is a well-known fact that insects being widely distributed became more problematic in tropical climate. Of 1.5 million species of insects so far described few are so conspicuous in their presence due to their ability to develop rapidly and becoming serious by attacking food crops directly and indirectly. • In developing country like ours insects are dominating over other pests by acquiring characters like resistance to toxic chemicals, and resurgence, particularly in intensive crop management regions of the country. • The losses caused by insect pests like Spodoptera, Heliothis , Whitefly and Aphids are so enormous that these made the farmer to disturb the present ecosystems with continuous use of excessive insecticides. • Insect pests cause huge losses ranging from 5-80%, even to an extent of 100% some times. One of the most universally accepted estimate was that insect pests cause about 10% loss annually in India , which accounts to 6000 crores, and varies depending on National Income. • Acute food shortage following World War II and Bengal Famine (1943) due to failure of paddy crop, because of disease, indicates the severity of the loss, caused by the pests. • It has already been estimated that rats alone consume about 2-3 million tons of food grains annually. • The insects in storage on an average consume and spoil an additional 4 million tons of grains every year (coffee cultivation disappeared from Ceylone due to leaf rust) • All this indicates the importance of plant protection by which we can serve millions of tons of food grains, which are otherwise eaten away by different pests. • The losses caused by different pests is furnished below (Pesticide Information, 1995) Pests Loss caused (in percentage) Insects 20 Storage Pests 7 Diseases 26 Weeds 33 Rodents 6 Miscellaneous 8 Total 100

History of Crop Protection: • The history of insecticides may go back to 2500 BC, when Sumerians knew the acaricidal and insecticidal properties of sulfur . Pest control tactics were mentioned occasionally in writings of the ancient Chinese, Sumerian, and Egyptian scholars. Many of these tactics were embedded in religion or superstition, but a few had real scientific merit. • In China, about 1200 BC, chalk and wood ash were used for controlling insects in enclosed spaces, plant extracts were used for treatment of stored grain and arsenic sulfide for human lice. Predatory ants (Oecophylla smaragdina), for example, were used in China as early as 1200 B.C. to protect citrus groves from caterpillars and wood boring beetles . Ropes or bamboo sticks tied between adjacent branches helped the ants move easily from place to place. • The Chinese recognized the use of mercury and arsenic for body louse control (100-200 AD), and white arsenic was used to protect rice plants from insect attack as early as 400 AD. These few examples are but a minute sampling of the many diverse concoctions and substances

which man has used in his defense against insect competitors over the centuries. 53

• A passage in Homer's Iliad (8th century B.C.) describes the use of fire to drive locusts into the sea, and the ancient Egyptians organized long lines of human drovers to repel swarms of invading locusts. Pythagorus, a Greek philosopher and mathematician, was credited with clearing malaria from a Sicilian town during the 6th century B.C. by instructing its residents to drain the marshes. Chemical substances that purportedly killed or repelled insects were in common usage. Many of these were of questionable value, but some worked, and a few are still in use today. Some of the inorganic compounds, such as sulfur and arsenic, have well- established insecticidal activity. And modern science has only recently come to recognize that many plant extracts used by ancient apothecaries (e.g, lemon oil, wormwood, hellebore, fleabane, etc.) do indeed contain compounds with useful activity against insects. • The ancient Greeks and Romans, in the 19 th century used sulfur, arsenicals, fluorides, soaps, kerosene and various botanicals, of which nicotine, pyrethrum, sabadilla and quassia appear to have been most widely used. • The chemical tools for insect control have evolved rapidly in the last 100 years; starting with inorganic agents such as lime sulfur and arsenicals and augmented by natural products such as pyrethrum, rotenone and nicotine , whose agricultural uses were beginning to be established by 1870 . At the time of their introduction such materials seemed to represent a revolutionary shift in the balance between man and insects, providing for the first time reliable tools to combat important insect pests. However, few years later they began to show their deficiencies in such characteristics as potency, flexibility of use, variability in composition, and in the limited range of insects, which could be controlled. In the case of the arsenicals, environmental persistence and hazards to the applicator and consumer of treated produce led to the first notable public concern regarding pesticide hazards and to the detection of residues which exceeded established tolerances for arsenic in foodstuffs. • With the Renaissance, people began to view insects less as a punishment from God and more as members of a natural world that could be studied and controlled. A renewed interest developed in insects both as organisms and as pests. More accurate observations of natural history and behavior led to more inventive control practices. Hand labor was used extensively in early pest control, but cultural, physical, and chemical practices also evolved. Franz Ernst Brückmann, a German physician who lived in the early 1700's, designed the first mechanical traps for various insects . His fly traps consisted of a wooden box baited with a sweet attractant and equipped with a spring-loaded lid. When several flies had settled inside the trap, the lid was snapped shut to trap the flies inside. The volume of the trap was then decreased by sliding the ends of the box together and squashing the flies against their bait. Brückmann also designed flea traps. They were hollow, perforated cylinders, baited with blood or honey, and worn around the neck as a pendant. For a time, these flea traps, crafted from ivory or silver and often ornate in design, were popular fashion accessories worn by the aristocracy of Western Europe. • Since the late 1800's, entomologists and chemists have made outstanding progress in the technology of pest control. Today's arsenal of weapons is large and diverse, encompassing legal, cultural, physical, genetic, and biological tactics, in addition to the well-known chemical pesticides. In general, all of these tactics work in at least one of the following ways: They kill the pest directly-usually by exposing it to lethal substances or unsuitable environmental conditions. They reduce the reproductive potential of a pest population-often by modifying its environment (biotic or abiotic) or by restricting its movement. They modify the pest's behavior to make it less troublesome (attract it, repel it, confuse it, exclude it, mislead it). • The first recorded use of a synthetic organic insecticide was that of dinitro-o-cresol, in 1892 , and by the 1930s a range of such compounds was discovered, which had limited use. • From the 1920s on, the increasing power of insecticides as tools for insect control led to their

growing predominance as an approach to insect control, with some justification, to the neglect of studies on pest biology and ecology and of alternative methods for insect control. 54

• The first four decades of the 20 th century saw significant progress in the synthesis of insecticides and the standardization of techniques such as the bioassay and the exploration of the relationship between chemical structure and biological activities. • Paul Müller of the J.R.Geigy Company, Switzerland, discovered the insecticidal properties of DDT in 1939 . Its first important use was to combat malaria and typhus by the Western allies during World War II. This marked the era of the chlorinated hydrocarbon insecticides, with the subsequent synthesis of hexachlorocyclohexane (HCH) and the cyclodiene insecticides (aldrin, dieldrin, endrin, and endosulfan). • Cyclodiene compounds are a group of highly active insecticides. However, many of them have long persistency and their use is restricted. They include chlordane, heptachlor, aldrin, dieldrin, isodrin, endrin, endosulfan, mirex, chlordecone, and the chlorinated terpene, camphechlor (toxaphene). This is a group of highly chlorinated insecticides prepared by the diene-synthesis or Diels-Alder reaction . These insecticides are usually referred as first- generation insecticides. These insecticides, however, were generally persistent and had long residual properties. The stability and hydrophobicity resulted in the contamination of the environment, and bioaccumulation in the body of many animals. Though this was a concern of thoughtful scientists but it was Rachel Carson's Silent Spring in1962 that served to focus public concern and necessitated speeded political action. As a result, during the 1970s, the organochlorines were subject to regulation and one by one their uses were cancelled in the US, Europe and Japan. Presently in India, among this group, only dicofol, lindane and endosulfan are allowed on agricultural crops, while DDT and HCH are allowed only for the control of mosquitoes. • In Germany, experiments were on the way with the synthesis of organophosphorus (OP) compounds to replace nicotine. Gerhard Schrader synthesized three OP insecticides ; viz., HETP, parathion and Schradan that were commercialized and used on a large scale despite their high toxicity to mammals . In attempts to lower their mammalian toxicity and retain or increase their efficacy, several hundred OP insecticides have been developed since then. However, many of these newer compounds were not without serious faults. The organophosphates in too many cases had high mammalian toxicity. Even today this group is responsible for the majority of accidental deaths attributable to pesticides. In 1971 the use of several of the most toxic organo-phosphates was prohibited in Japan because of their hazard. American Cynamide introduced a carbamate insecticide, carbaryl in 1950 . The OP and Oragano -Carbamate insecticides referred as second-generation insecticides. • Scientists in UK and Japan were working on the development of analogues of pyrethrin and during the period between 1949 and 1970 the synthetic pyrethroids like allethrin and resmethrin were developed. However, these could only be used indoors due to their low photostability . Between 1970 and 1977 a number of photostable pyrethroids like permethrin, fenvalerale etc. were introduced for agricultural use. The photostable pyrethroids led to profound changes in the use patterns of insecticides. These exceptionally potent, biodegradable compounds were effective in the field at rates as low as 20 g/ha, which is 10-to 100-fold lower than most conventional insecticides and hence reduced the burden of chemicals in the environment. Unfortunately, the synthetic pyrethroids also proved not the perfect answer to the insecticide problem since they have high toxicity to many aquatic species, vertebrates and invertebrates, and to many beneficial insects. The potential for resistance to this group also appears to be high. These synthetic pyrethroids usually referred as third-generation insecticides. • Apart from the environmental problems, other problems also cropped up as synthetic organic insecticides came into widespread use. Reports of insect resistance to synthetic pyrethroids started pouring in from mid 80s onwards. This, however, was not a new phenomenon, since it was observed between 1910 and 1930 with lime sulfur and hydrogen cyanide in scale insects, and arsenicals in the codling moth, Laspeyresia pomonella .

• As early as 1956, Williams found that hormonally active compounds extracted from male Cecropia moths applied topically to silkworm pupae caused lethal derangements of

metamorphosis. Later studies of authentic JH applied to larvae of the cecropia silkmoth, as 55

well as of naturally occurring and synthetic analogues with similar effects, led to the proposal of "the third generation insecticides". In the past thirty years numerous JH analogues have been synthesized and tested. Some of these, such as methoprene and hydroprene, have been commercialised. The juvenoids and other natural chemicals which are based on behavior (JH, Ecdysones, and Chitin Synthesis Inhibitors) control acting on hormonal systems, are potentially used, and are termed as third-generation insecticides . • The search for newer molecules is ongoing process, and in last few years, new molecules like neo-nicotinoids, pyrroles etc. have been commercially used successfully.

Plant Protection in India: • On August 25, 1897 Sir Ronald Ross discovered malarial parasite in Mosquito . The day is observed as World Mosquito Day. “A text book of Medical Entomology” by Patton and Craigg (1931). Central Malaria bureau in 1909. National malaria control programme-1953 changed to “National Malaria Eradication Programme” in 1958. • IARI started in 1903 in Pusa, Bihar, and then shifted to New Delhi 1937. • ICAR established in 1939. • Plague commission in 1905 • Locust warning station in India was established in 1939 . The “Locust Control and Research“ is one of the divisions of the Directorate of Plant Protection, Quarantine and Storage, being implemented through an Organization known as Locust Warning Organization (LWO) established in 1939, to monitor, forewarn and control of Desert Locust (an international pest) with its 10 Circle Offices located at Bikaner, Jaisalmer, Barmer, Palanpur, Bhuj, Jalore, Phalodi, Nagaur, Suratgarh and Churu with its field Headquarters at Jodhpur and a Central Headquarter Faridabad . Besides, there is one Field Station for Investigations on Locusts (FSIL) situated at Bikaner. To strengthen the locust monitoring and forecasting, a Remote Sensing Laboratory has also been set up to prepare vegetation maps based on satellite imageries for locust forecasting. • 1946-GOI started Directorate of Plant Protection, Quarantine and Storage (DPPQS), at Faridabad, UP. In AP, NPPTI (National Plant Protection Training Institute) was established ay Hyderabad in 1966, which is renamed as National Institute of Plant Health Management (NIPHM) in 2008.

Plant Protection Organization in India: • Plant Protection continues to play a significant role in achieving targets of crops production. The major thrust areas of plant protection are promotion of Integrated Pest management, ensuring availability of safe and quality pesticides for sustaining crop production from the ravages of pests and diseases, streamlining the quarantine measures for accelerating the introduction of new high yielding crop varieties, besides eliminating the chances of entry of exotic pests and for human resource development including empowerment of women in plant protection skills . • DPPQS, GOI is the principle organization plans, coordinates, all activities pertaining to Plant Protection in India. The thrust areas are, IPM through CIPMCs, Pesticide Quality control through Insecticide Act, Locust Management through ILO, Quarantine activities through Plant Quarantine Organization of India (PQOI), and Pesticide Residue Monitoring Scheme. • Keeping in view the ill effects of pesticide and also National policy on Agriculture, Integrated Pest Management (IPM) approach has been adopted as a cardinal principle and main plank of plant protection in the country in the overall crop production programme. • The Locust Warning Organization ( LWO) keeps constant vigil on locust activity in the scheduled desert Area of 2.00 lakh sq. km in coordination with Remote Sensing Laboratory, Jodhpur, the locust control potential of LWO (10 circles and 1 hq.) and locust research 56

facilities at FSIL, Bikaner. Keeping in view the locust invasion of 1993, Locust Surveillance in the strategic areas has been intensified. • Quality control of pesticides accorded highest priority to ensure that the agro-chemicals used have the requisite degree of efficacy, under Insecticide Act 1968 . • In Plant Quarantine, besides on going activities, Pest Risk Analysis (PRA) and post entry quarantine surveillance are being started, which has become essential in the light of World Trade Organization (WTO) agreement. Considering this fact, Ministry of Agriculture issued a notification entitled “ The Plant Quarantine (Regulation of Import into India) order 2003 ” replacing the “The Plants, Fruits & seeds (Regulation of Import into India) order 1989”. The new regulation is effective from 01.01.2004.

Methods of Pest Control: • Any factor that is capable of making life hard for the insect that will repel or interfere with its feeding, mating, reproduction or dispersal can be taken as a method of insect control in its broadest application. • Most of the control tactics that are commonly used today can be grouped into two broad categories: natural controls and artificial controls. • By definition, a natural control may be any environmental factor that keeps a pest population below its economic injury level. The population is kept under check by the environmental resistance without interference of man . Examples might include geographic barriers, cold temperatures, or natural enemies that keep population growth in check. • Artificial controls , on the other hand, employ products or processes of human origin to modify a pest's distribution, behavior or physiology. These methods are employed by human being. In fact, some of our most effective tactics are natural controls that we can improve, enhance, accelerate, or augment by appropriate human intervention. • Depending on the time of taking action, the applied methods may be preventive or prophylactic, and curative or remedial measures.

Methods of Pest Control

Natural Control Artificial Control

Preventive / Prohylactic Curative / Remedial

Cul tural Methods

Mechanical Methods

Physical Methods

Biological Methods

Chemical Methods

Legal Methods

Biotechnology Methods

Lecture: 11 Cultural control-normal cultural practices which incidentally control the pests and cultural practices recommended specifically against certain pests. Mechanical control-different mechanical methods of pest control with examples.

Cultural Methods: • Simple modifications of a pest's environment or habitat often prove to be effective methods of pest control, and such tactics are known as cultural control practices because they frequently involve variations of standard horticultural, silvicultural, or animal husbandry practices. Since these control tactics usually modify the relationships between a pest population and its natural environment, they are also known, less commonly, as ecological control methods . • Simplicity, eco-friendly, easy to implement and low cost are the primary advantages of cultural control tactics , and disadvantages are few as long as these tactics are compatible with a farmer's other management objectives (high yields, mechanization, etc.). Unfortunately, there are still a wide variety of insect pests that cannot be suppressed by cultural methods alone. • The control of insects through adoption of ordinary farm practices in such a way that the insects are either eliminated or reduced in their populations. There are two categories of cultural control methods; Normal (which control one or few or many insects naturally) and Special (which are implemented specially for certain insects).

Cultural Methods

Normal Methods Special Methods

Proper Preparatory Adjusting sowing / Cultivation planting time

Growing suitable varieties Trap Crops

Crop Rotation Managed application of Water

Changing system of Managed application of cultivation Fertilizers

Mixed Cropping Trach Mulching / Earthing Up

Clean Cultivation Alley Ways

Periodical Drying of Seeds &

Stored Produce

NORMAL CULTURAL METHODS: These methods improve the yields and also keep the insect pest population below threshold levels. Proper preparatory cultivation: • Several insects which live or hide under soil in different forms / stages (larvae, pupae, grubs etc.) get exposed to sun as well as other predators such as birds. • Summer deep ploughing exposes all resting stages of insects, such as larva and pupa to abiotic and biotic factors. For example, summer deep ploughing in Groundnut exposes pupa of Red Hairy Caterpillar Amsacta spp. Growing suitable varieties: • Selection of suitable resistant / tolerant varieties or hybrids helps in managing the pest population, and also gives good yields in endemic areas. MTU 2067 (Chaitanya) Resistant to BPH MTU 2077 (Krishnaveni) Resistant to BPH IR 64 Resistant to BPH BPT 5204 (Mahsuri) Susceptible to BPH, Gall Midge JGL 384 (Polasa Prabha) Tolerant to BPH, Gall Midge JGL 1798 (Jagtial Sannalu) Resistant to Gall Midge MTU 1010 (Cottn Dora Sannalu) Tolerant to BPH Surekha, Pothana (WGL 22245) Resistant to Gall Midge Sumathi (RNR 18833) Tolerant to Gall Midge LK 861, LPS 141 cotton Whitefly resistant L 603, L 604 cotton Jassids tolerant Crop Rotation: • Crop Rotation is one of the oldest and most effective cultural control strategies. Growing a single crop year after year in the same field gives pest populations sufficient time to become established and build up to damaging levels. • The Crop rotation is stated as growing one crop after another on the same piece of land in different timings (seasons) without impairing the soil fertility. It is a planned order of planting specific crops on the same field. Crop rotation also means that succeeding crops are of a different genus, species, subspecies or variety than previous crop. Examples would be legume after wheat, row crops after small grains, cereals after legumes, etc. Rotating the field to a different type of crop can break the life cycle by starving pests that cannot adapt to a different host plant. • Rotation schemes also prove successful for controlling pests in pasture lands. • Insects can be controlled entirely or partially by rotations. The insect populations go up within a cropping system where only one or two crops are continuously grown over the time. The insects are able to develop a kind of parasitic relationship with the crop plants and perpetuate till the system is changed by alteration with crops. The feeding habit and habitat of the insects are destroyed by rotations. Insects such as maize borer and stem weevil readily migrate to nearby or distant fields in absence of maize. In such cases, only partial control can be obtained by rotation. Increasing field isolation from fields seeded with the same crop, help controlling of insects. • Crop rotation schemes work because they increase the diversity of a pest's environment and create discontinuity in its food supply. As a rule, rotations are most likely to be practical and effective when they are used against pests that: attack annual or biennial crops, have a relatively narrow host range, cannot move easily from one field to another, and are present before the crop is planted.

• Plants within the same taxonomic family tend to have similar pests and pathogens. The crop rotation will help to avoid the buildup of pathogens and pests that often occurs when one species is continuously cropped. • For instance if annual vegetable crops are grown in the same place year after year, there is a risk that soil borne pests and diseases will become a problem. • Growing bhendi crop after cotton increase the pest infestation (spotted boll worm Earias vitella, Earias insulana ) (leaf hoppers Amrasca biguttula biguttula ), whiteflies (Bemisia tabaci ), and hence if the non-host crop is grown after the host-crop, insect population reduces, like growing cereals followed by pulses, since the insect pest sps of cereals are different from pulses. • For example, root-knot nematode is a serious problem for some plants in warm climates and sandy soils, where it slowly builds up to high levels in the soil, and can severely damage plant productivity by cutting off circulation from the plant roots. Growing a crop that is not a host for root-knot nematode for one season greatly reduces the level of the nematode in the soil, thus making it possible to grow a susceptible crop the following season without needing soil fumigation. • Diamond backed moth (Plutella xylostella ) can be controlled by rotating cabbage with non-cruciferous crops. Change in the system of cultivation : • Change of banana from perennial crop to annual crop through regular planting of seed materials (not by ratoon system) helps in reduction of stem weevil ( Odoiporus longicollois ) in addition in increase of yields. Mixed cropping : • Intercropping (also known as mixed cropping) is another way to reduce pest populations by increasing environmental diversity . In some cases, intercropping lowers the overall attractiveness of the environment, as when host and non-host plants are mixed together in a single planting. But in other cases, intercropping may concentrate the pest in a smaller, more manageable area so it can be controlled by some other tactic. • Inter-cropping Cowpea with Sorghum can attract polyphagous insect pests on to sorghum which is leass value crop. • Cotton system is ideally suitable for intercropping because of the relatively longer duration and its slow growth in the initial stages. The common practice of cotton cultivation is inter or mixed cropping with pulses which reduces the sucking pest complex on cotton. Similarly, planting of few rows of sorghum or maize in cotton reduces insect pest population due to disturbance of host selection process of insects. • Intercropping of Pigeonpea in Sunflower crop @ 1:2 reduces Bihar Hairy Ceterpillar Spilosoma oblique attack. • Strips of alfalfa, for example, are sometimes interplanted with cotton as a trap crop for lygus bugs (Miridae). The alfalfa, which attracts lygus bugs more strongly than cotton, is usually treated with an insecticide to kill the bugs before they move into adjacent fields of cotton. Clean cultivation: • Sanitation is an important cultural strategy for protection of crops from arthropod (insect and mite) pests. Clean cultivation is often recommended as a way to eliminate shelter and/or overwintering sites for pest populations. • Sanitation for crops requires the destruction or removal of not only infested materials, and also potential sources of infestation. Effective sanitation practices reduce and

delay the onset of insect pest problems, and eventually can eliminate or minimize pest 60

problems. It is easier and less expensive to exclude pests than to control them after they appear. • Removal of weeds / unwanted plants which act as alternate hosts helps in reduces in pest build-up. For example, paddy gall midge breeds on grasses like Cynodon, Panicium , and hence removal affects of gall midge survival. Trimming field bunds in paddy reduces grasshopper populations, since they eggs on weeds. Weeds also offer shelter for many moths. Fruit sucking moth spends their larval stage on climber weeds (Cocculus pendulus, C. hirsutus, Tinospora cardifolia ) belongs to Family Menispermaceae, usually found around orachards, and the adult damage the fruit crops. • Systematic removal and cutting of infested plants / plant parts keeps down the subsequent infestation. Eg: removal of sugarcane shoots affected by borers, twigs of brinjal affected by shoot and fruit borer ( Leucinodes arbonalis ), pruning of dried branches of citrus eliminates scales and stem borer, clipping tips of rice nurseries eliminates paddy stem borer (Scirpophaga incertulas) egg masses, ploughing and hoeing helps to expose the insect life cycles. • Removal of plant residues / debris which harbor the insect stages helps in reducing the pest density. Removing crop debris from cotton fields after harvest eliminates overwintering populations of pink bollworms ( Pectinophora gossypiella ), european corn borers ( Ostrinia nubilalis ), and sugarcane borers ( Diatraea saccharalis ). Collecting dropped fruit from beneath an apple tree reduces the next season's population of apple maggots ( Rhagoletis pomonella ), codling moths ( Cydia pomonella ). Removal of stubbles in paddy and sugarcane after harvest of the crop destroys resting stages of stem borers. Periodical drying of seeds / stored produce: • Helps in reduction of stored grain pests and also helps in cross infestation.

SPECIAL CULTURAL METHODS: These methods are intended for targeting specific pests. Adjusting sowing / planting time: • In some crops, it is possible to create discontinuity in the pest's food supply simply by altering the time of year for planting or harvesting. This strategy, often known as phenological asynchrony , allows farmers to manage their crop so it remains " out of phase " with pest populations. • Sweet corn, for example, can escape most injury from corn earworms ( Helicoverpa zea ) if it is planted in early spring and harvested before larvae mature. • Early planted rice crop escapes gall midge damage. This mechanism called as Psuedo-resistance as described by Painter, since the plants evade or escape the pest attack due to changes in environment and other factors, may be susceptible to the pest if occurs at right time and right stage of the crop. • Early planting in kharif and late planting in rabi minimizes the pest infestation on paddy stem borer ( Scirpophaga incertulas ). • Early sowing of redgram escapes the pod-fly (Melanagromyza obtuse) damage. • Delaying sunhemp sowing till the onset of south-west monsoon avoids sunhemp hairy caterpillar attack. • Careful timing of harvest dates in alfalfa can cause high mortality in populations of alfalfa weevil ( Hypera postica ) and alfalfa caterpillar ( Colias eurytheme ) by removing edible foliage before the larvae have completed development. 61

• Harvest timing is often the most practical method available to foresters for controlling bark beetle (Scolytidae) infestations in pine plantations. Since trees become more susceptible to beetle outbreaks as they grow older, good management dictates that timber stands be harvested for lumber before the trees reach full maturity. Trap crops: • Pests are strongly attracted to certain plants. When these plants are sown in the main field or along the borders, the pests gather on them. Raising trap crops as inter and/or border crops is an important cropping system approach. • The trap crop distinctly attractive to the pest when compared to the main crop. It provides protection either by preventing the pest from reaching the main crop or by restricting them to a certain part of the field where they can be economically destroyed. Generally, these trap crops are planted on the borders of main crop. Mustard along with cabbage is a trap crop for the control of the Diamond Backed Moth , aphids and the Leaf Webber. African marigold @ 100 plants/acre, in cotton / chilli / tomato is a good trap crop for the Helicoverpa armigera, besides it also attracts the adults of the leaf minor which lay eggs on its leaves. Similarly, planting Hibiscus @ 100 plants / acre in cotton also attracts insect pests. Castor is a good trap crop for tobacco cater pillar (Spodoptera litura ) in chilli / cotton/ tomato etc. Maize plants can be a trap crop to attract fruit fly adults in vegetable cultivation where the fruit fly (Bactrocera cucurbiate ) is a major problem. Tomato is a good trap crop in citrus for fruit sucking moths (Othereis materna ) Managed application of water: • This method can have a big impact on the survival of pest populations in some crops. • Regular rainfall (or overhead irrigation) can significantly reduce infestations of two spotted spider mites ( Tetranychus urticae ) in tree fruits. • For paddy cutworms, paddy swarming caters pillars, ragi cutworms, flooding the fields float these caterpillars leaving the plants. • Good irrigation keeps plants healthy, vigorous, and more resistant to insect injury. • Draining the paddy fields can reduce BPH populations, and also paddy caseworm which travel one plant to other through water. It is not unusual for small amounts of injury to actually stimulate compensatory growth in healthy plants. Managed application of fertilizers: • This method can have good positive impact on crop growth as well as negative impact on some specific pest populations. Higher does of nitrogenous fertilizers increases pest attack while pottasic fertilizer make plant more resistant. • Over dose of nitrogen application leads to stem borer attack in paddy, sucking pests in cotton, chilli etc. • Root weevil attack in rice can minimized through application on 20kg ammonium phosphate and 40kg super phosphate/ha. Trash mulching / earthing up: • Trash mulching / earthing up at month after planting of sugarcane reduces early stem borer (Chilo infuscatellus) attack in sugar cane. Alley Ways in paddy : • Leaving gaps of 0.5m for every 5m width in paddy fields increases the aeration and light, and BPH (Brown Plant Hopper-Nilaparvatha lugens ) incidence come down under highly aerated conditions.

Advantages of Cultural methods: As we are using same cultural practices no extra cost is required. This method is safe for application. Disadvantages of Cultural methods: • This method is effective for single pest only. • There are no visible results observed. • This method is not effective at epidemic condition. • Detailed knowledge of biology of pest is required for this purpose.

MECHANICAL METHODS: The control of insects by mechanical methods is based on the principles of removal and direct destruction . Mechanical control methods involve using barriers, or physical removal to prevent or reduce pest problems.

Preventive barriers: • An example of a more common physical barrier is the window screening we use to keep pests out of our homes. Eg: mosquito nets and fly proof cages. • Trenching around crops prevents movement of army worms, like red hairy caterpillar (Amsacta albistriga ) in groundnut, swarming caterpillar ( Spodoptera mauritia ) in paddy, and grasshoppers. Ditches or moats with steep vertical walls are occasionally used as barriers to keep crawling insects (e.g., chinch bugs or whitefringed beetles) from migrating out of one field and into another. Pitfall traps are dug at 3-5 meter intervals in the ditch and filled with kerosene or creosote to kill the pests. • Bagging in pomegranate fruits avoids infestation of pomegranate butterfly ( Virachola Isocrates ). Fruit sucking moth on citrus (Otheiris spp.) or pomegranate suck the juice with the help of stout which can be prevented by bagging fruits. • Water as barrier: Domestic pest like ant can be prevented with water. Hand picking: • Egg masses and larvae or nymphs and sluggish adults can be handpicked from plants / plant parts. • Egg masses of paddy stem borer ( Scirpophaga incertulas ) can be handpicked and by leaf tip clipping during transplantation. • Egg masses of tobacco caterpillar ( Spodoptera litura ) can be handpicked. • Egg masses of red hairy cater pillar ( Amsacta albistraiga ) can be handpicked. • Early larval instars of Spodoptera can be handpicked from castor leaves. • Most of the adults can be picked up using sweeping nets. • Hand picking of egg masses and adults of Colorado potato beetle ( Leptinotarsa decemlineata ) was followed 100 years ago. Jarring & Shaking : • Shaking redgram plants for Helicoverpa larvae. • Shaking bushes and other plants for collecting damaged parts, eggs and larvae. • In 1920’s some farmers dragged gunny bags over cotton plants to collect and destroy infested squares in cotton. • Running a rope over paddy crop for removal of case worms. • Adults of whitegrub gathers on neem or babhul tree so by shaking tree they can be collected and destroyed

Extraction of rhinoceros beetle ( Oryctes rhinoceros ) from the coconut crown using an arrow headed rod. Tin collars over coconut plants prevent rat damage. Sticky bands around tree trunks can be used against red tree ant . Mealy bugs on mango come on soil for egg laying which can be prevented by putting sticky bands on stem. Beating with stick: When swarm of locust comes, it can be beaten with stick. Sieving and winnowing seed materials / food grains for stored grain pests. Pests of stored grains can be removed with this method. One effective method for controlling gypsy moth larvae on small numbers of trees is to put a band of folded burlap around the tree trunk to provide an artificial resting site for the caterpillars, and then destroy the caterpillars that gather there. Fruit and shade trees can be protected from various pests (e.g., plum curculio, gypsy moth, and codling moth) by tying a band of folded burlap around the trunk with its open side facing down. As insects climb up the trunk, they are waylaid in the folds of burlap which can be treated with insecticide or inspected daily to collect the pests. Advantage of Mechanical methods: Skilled labours are not required. Cost required is very less. There are no any side effects. Limitations of Mechanical methods: • Time and labour requirement is high. • This method is applicable only on small scale. • This requires repeated application.

Lecture: 12 Physical control-use of inert carriers against stored product insects-steam sterilization-sterile male technique-solarization-solar radiation-light traps-flame throwers etc. Legislative measures- importance of quarantine-examples of exotic pests-different legislative measures enforced in different countries and also in India in restricting the movement of agricultural products with in the country and to outside.

PHYSICAL METHODS: The control of insects by physical methods is based on the principles of using some physical forces for insect eradication. Physical control methods involve using traps (light, pheromone, color etc.), physical materials (clay, boric powder), or physical energy (X ray, heat, water etc.) for removal or prevent or reduce pest.

Traps: We can use traps to catch certain pests, to protect plants from insect attack. • Light traps (visual lures), are the most commonly used physical method. Hundreds of species of moths, beetles, flies, and other insects, most of which are not pests, are attracted to artificial light. They may fly to lights throughout the night or only during certain hours. Key pests that are attracted to light include the Tobacco caterpillar, Borers / bollworms, Paddy stem borer, codling moth, cabbage looper, many cutworms and armyworms, diamondback moth, several leaf roller moths, potato leafhopper, bark beetles, adults of root grubs, house fly, stable fly, and several mosquitoes. • Lights and light traps are used with varying degrees of success in monitoring populations and in mass trapping. Light traps provide useful information about the timing, relative abundance, or species composition of flights of pod borer, tobacco caterpillar, many noctuids, white grubs, and a few other pests. • At the other end of the technology spectrum are the electronic bug killers . These high- tech fly swatters produce an ultraviolet glow that attracts flying insects to an untimely death on an electrified grid. Although bug zappers probably kill more beneficial insects than pests, their owners seem to sleep better at night with the reassuring sound of bugs sizzling on the grill. From its inception in the late 1970's, the market for these devices has grown into an industry with annual sales approaching $100 million. Pest- O-Flash , product of PCI, electronic flying insect control system which attracts, kills and collects flies and other insects, in which UV tube is used for attracting flies. • Specific colors are attractive to someday-flying insects. For example, yellow objects (yellow sticky traps) attract many insects and are often used in traps designed to capture winged aphids and adult whiteflies . Red spheres and yellow cards attract apple maggot flies . Like other attractants, colored objects can be used in traps for monitoring or mass trapping. Yellow plastic tubs filled with water , for example, are used to monitor the flights of aphids in crops where these insects are important vectors of plant viruses. Aphids attracted to the yellow tub land on the water and are unable to escape. Yellow, sticky-coated cards or plastic cups are widely used in mass trapping programs to help control whiteflies in greenhouses. Although recommended trap densities in greenhouses are based on studies involving only a few crops, recommendations of 1 trap per 5 square yards or 1 trap every 3 to 4 feet along benches are common. • Fly paper and sticky boards , for example, are often used in greenhouses to control whiteflies or leafhoppers.

• Pheromones, allemones, other chemical attractants also used in traps (This is explained in behavioral methods).

Physical materials: • In the 1930's and 1940's it was common practice for a farmer to hitch a bale of chicken wire behind a team of horses (or a tractor) and drive it through his fields to stir up dust. When the dust settled, it gave the insect pests an abrasive coating that gradually rubbed away their cuticular waxes and caused them to die from dehydration . Although this is certainly not the most reliable method of pest control, it does explain why crops planted near the edge of a well-travelled dirt road often have less insect injury than those on the opposite side of the same field. • A material called drie-die marketed in USA consists of highly porous, finely divided silica gel which when applied to insects in field, abrades insect cuticle, resulting in loss of moisture and finally death of insect. This material is mainly used in stored grains . • Similarly, kaolinic-clay after successive activation with acid and heat can be mixed with stored grain. This clay material absorbs the lipid layer of insect in the exoskeleton, thus allowing to loss moisture, leading to death of insect . • Generally, at household level, to store the rice and other pulses, boric powder is added, to avoid the pest infestation, which causes damage to insect exoskeleton. Temperature extremes can be used to kill insects or prevent their injury. • Cold storage of agricultural products prolongs their shelf life and retards the development of insect pests. • Heat treatments (steam sterilization ) are sometimes used in place of fumigation to kill insect larvae in certain types of produce. Mangoes, for example, are submersed in hot water baths (115°F for 68 minutes) to kill the eggs and larvae of fruit flies (Tephritidae) prior to export. • Vapor heat treatment (VHT) is followed for mango intended for export for killing fruit fly and nut weevil. • Hot water treatment to sugarcane prevents damage by scales. • Artificial cooling and heating of stored products will prevent insect development. Stored products exposed to 55 0C for 3 hours kill insects. • In chittor districts, farmer’s burns the groundnut residues (community camp fires ) during summer and pre-monsoon season to attract the red hairy cater pillars and eventually die falling in fire. This method is widely followed on community basis. • Flame throwers: Burning of caterpillar patches, weed patches etc. using flame throw burner . This is also a common practice for killing locusts. • Solarization: Soil solarization , a hydrothermal method of managing nematodes, diseases, insects, and weeds, is accomplished by passive heating of moist soil covered with transparent plastic sheeting. Because of the lethal effects from high soil temperature, solarization must be conducted before crops are planted. This is the common method followed for the management of nematodes inhabiting inside soil. • Sun drying: Stored grain pests can be easily controlled by sun drying. Physical forces: • Some aphids and mites can be knocked off the foliage by spraying the plant with a stream of water. Use of radiation: • X-rays and Gamma rays used for making insect sterile . • Sterile insect technique is a method of biological control, whereby millions of sterile insects are released. The released insects are normally male as it is the female that

causes the damage, usually by laying eggs in the crop, or, in the case of mosquitoes,

taking a blood meal from humans. The sterile males compete with the wild males for 66

female insects. If a female mates with a sterile male then it will have no offspring, thus reducing the next generation's population. Repeated release of insects can eventually wipe out a population, though it is often more useful to consider controlling the population rather than eradicating it. The technique has successfully been used to eradicate the Screw-worm fly (Cochliomyia hominivorax ) in areas of North America. There have also been many successes in controlling species of fruit flies, most particularly the Medfly (Ceratitis capitata ), and the Mexican fruit fly ( Anastrepha ludens ). • Gamma irradiation: Mangoes for export are treated with gamma rays (irradiation treatment) for the control of mango nut weevil ( Sternochetus mangiferae ). Ultra sonic sounds: are used to deter away rats.

LEGISLATIVE METHODS: Importance of Plant Quarantine: • Quarantine is voluntary or compulsory isolation, typically to contain the spread of something considered dangerous, often but not always disease. • In early days, there were no restrictions on the transport of plants and animals from one country to another, since the danger involved is not realized, which resulted in introduction of new pests. • In many countries many of the dangerous pests have frequently been found to be foreign pests and they inflict greater damage than the indigenous pests. The following are the exotic pests introduced accidentally into India, and became najor threats to Indian Agricultural Economy: Name of the Insect Pest Scientific Name Subabul psyllid Heteropsylla cubana American Serpentine leaf miner Liriomyza trifolii Coffee berry borer Hypothenemus hampei Spiralling white fly Aleurodicus disperses Coconut mite Aceria quadrasticus Diamond backed moth on cauliflower Plutella xylostella Potato tuber moth Phthormaea operculella Cottony cushiony scale-polyphagous Icerya purchase Wooly aphid on Apple Eriosoma lanigerum Mealy bug in cotton-New Penacoccus solenopsus San Jose Scale Quadraspidiotus perniciosus Potato-Golden cyst nematode Globodera rostochiensis Giant African Snail Achatina fulica The scientists conducted a survey at 47 locations in the nine cotton-growing states, and found only two mealy bug species infesting the cotton plants from all nine states: the solenopsis mealy bug, Penacoccus solenopsis , and the pink hibiscus mealy bug, Maconellicoccus hirsutus . However, P. solenopsis was the predominant species, comprising 95 percent of the samples examined. Furthermore, the scientists confirmed that Penacoccus solenopsis is a new exotic species on Cotton to India originating in the US , where it was reported to damage cotton and other crops in 14 plant families. Mealy bugs (Hemiptera: Pseudococcidae) are small sap-sucking Insects, and some species cause severe economic damage to a wide range of vegetables, horticultural and field crops. Infested plants can exhibit general symptoms of distorted and bushy shoots, crinkled and/or twisted bunchy leaves, and stunted plants that may dry completely. Historically, mealy bugs were never considered major pests of cotton in India. There have been isolated reports of M. hirsutus on the native ‘desi’ species, Gossypium arboretum Gossypium herbaceum

in Punjab and on the new world cotton in Gujarat. But no published evidence of mealy bugs on Gossypium hirsutum which currently occupies more than 80 percent of the

cotton cultivated in the country. 67

• The first legal restrictions to hinder the spread of disease were enacted against human disease. • Plant quarantine may be defined as the restriction imposed by duly constituted authorities on the production, movement and existence of plants or plant materials, or animals or animal products or any other article or material or normal activity of persons and is brought under regulation in order that the introduction or spread of a pest may be prevented or limited or in order that the pest already introduced may be controlled or to avoid losses that would otherwise occur through the damage done by the pest or through the continuing cost of their control. • When plant pathogens are introduced into an area in which they did not previously exist, they are likely to cause much more catastrophic epidemics than do the existing pathogens. Some of the worst plant disease epidemics that have occurred throughout the world, for example the downy mildew of grapes in Europe and the bacterial canker of citrus . • It is extremely difficult to predict accurately whether an exotic organism will become established, and once established, become economically important. Factors which affect entry and establishment of an organism are (1) hitchhiking potential compared with natural dispersal; (2) ecological range of the pest as compared with ecological range of its host; (3) weather; (4) ease of colonization including reproductive potential, and (5) agricultural practices including pest management. • Plant materials from one country to another was realized when the grape vine mealy bug Phylloxera was introduced into France from USA by about 1860 and the San Jose Scale (Quadraspidiotus perniciosus) spread into USA in the later part of 18th century , which caused severe damage. • The first quarantine act came into existence in USA during 1905, while Govt of India passed Act II of 1914 entitled “Destructive Insect and Pests Act of II of 1914” (Pests Act). This was later supplemented by more comprehensive status in 1917. Plant Quarantine in India: • Plant Quarantine regulatory measures are operative through the "Destructive Insects & Pests Act, 1914 (Act 2 of 1914)" in the country. • The purpose and intent of this Act is to prevent the introduction of any insect, fungus or other pest, which is or may be destructive to crops. • The import of agricultural commodities is presently regulated through the Plant Quarantine (Regulation of Import into India) Order, 2003 issued under DIP Act, 1914 incorporating the provisions of New Policy on Seed Development, 1988. • Further, the significance of Plant Quarantine has increased in view of Globalization and liberalization in International trade of plants and plant material in the wake of Sanitary and Phytosanitary (SPS) Agreement under WTO. • The phytosanitary certification of agricultural commodities being exported is also undertaken through the scheme as per International Plant Protection Convention (IPPC), 1951. All the products intended for export should be issued Phytosanitary Certificate. • Plant Quarantine Organization India (National Plant Protection Organization-NPPO) works under the purview of Directorate of Plant Protection, Quarantine & Storage (DPPQS), Department of Agriculture & Cooperation, Ministry of Agriculture, GOI, Krishi Bhavan, New Delhi. • Joint Secretary (Plant Protection) will look after Directorate of Plant Protection, Quarantine & Storage (Faridabad, Haryana) headed by Plant Protection Advisor (PPA)

to GOI. 68

The primary objectives: • To prevent the introduction and spread of exotic pests that are destructive to crops by regulating/restricting the import of plants/plant products and • To facilitate safe global trade in agriculture by assisting the producers and exporters by providing a technically competent and reliable phytosanitary certificate system to meet the requirements of trading partners. The major activities: • Inspection of imported agricultural commodities for preventing the introduction of exotic pests and diseases inimical to Indian Fauna and Flora • Inspection of agricultural commodities meant for export as per the requirements of importing countries under International Plant Protection Convention (IPPC) • Detection of exotic pests and diseases already introduced for containing/ controlling them by adopting domestic quarantine regulations. • Undertaking Post Entry Quarantine Inspection in respect of identified planting materials. • Conducting the Pest Risk Analysis (PRA) to finalize phytosanitary requirements for import of plant/plant material. • The Sanitary and Phytosanitary (SPS) Agreement of WTO envisages application of Phytosanitary measures based on scientific justifications therefore it is imperative to conduct all Plant Quarantine inspections as per the International Standards/guidelines. Accordingly, the National Standards for Phytosanitary Measures (NSPMs) for some of the important activities have already been developed and adopted including the Guidelines for Development of National Standards for Phytosanitary Measures and six draft National Standards are under the process of approval. The Standards which are critical for our exports have been prioritized. Further, a National Integrated Fruit Fly Surveillance Programme is in vogue with a view to establish pest-free areas against fruit flies . Plant Quarantine in USA: • The Plant Quarantine Act , originally enacted in 1912, gave the Animal and Plant Health Inspection Service (APHIS) authority to regulate the importation and interstate movement of nursery stock and other plants that may carry pests and diseases that are harmful to agriculture. This Act has been superseded by the consolidated APHIS statute, the Plant Protection Act of 2000. • This authority is particularly important to the agency’s ability to prevent or limit the spread of harmful invasive species within or to a state or region of the United States. • "Protecting American agriculture" is the basic charge of the U.S. Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS). • APHIS provides leadership in ensuring the health and care of animals and plants. The agency improves agricultural productivity and competitiveness and contributes to the national economy and the public health. • The Animal and Plant Health Inspection Service is a multi-faceted Agency with a broad mission area that includes protecting and promoting U.S. agricultural health, regulating genetically engineered organisms, administering the Animal Welfare Act and carrying out wildlife damage management activities. These efforts support the overall mission of USDA, which is to protect and promote food, agriculture, natural resources and related issues. • To protect agricultural health, APHIS is on the job 24 hours a day, 7 days a week working to defend America’s animal and plant resources from agricultural pests and diseases. For example, if the Mediterranean fruit fly and Asian long-horned beetle, two major agricultural pests, were left unchecked, they would result in several billions of dollars in production and marketing losses annually . Similarly, if foot-and-mouth disease or highly pathogenic avian influenza were to become established in the United States, foreign trading partners could invoke trade restrictions and producers would suffer devastating losses. • In the event that a pest or disease of concern is detected, APHIS implements emergency protocols and partners with affected States to quickly manage or eradicate the outbreak. This aggressive approach has enabled APHIS to successfully prevent and respond to potential pest and disease

threats to U.S. agriculture. 69

• To promote the health of U.S. agriculture in the international trade arena, APHIS develops and advances science-based standards with trading partners to ensure America’s agricultural exports, worth more than $50 billion annually, are protected from unjustified restrictions. • In response to needs expressed by the American people and Congress, APHIS’ mission has expanded over the years to include such issues as wildlife damage and disease management; regulation of genetically engineered crops and animal welfare; and protection of public health and safety as well as natural resources that are vulnerable to invasive pests and pathogens. While carrying out its diverse protection responsibilities, APHIS makes every effort to address the needs of all stakeholders involved in the U.S. agricultural sector. • Inspections and quarantines are also operated by some state and local government agencies. The California Border Patrol, for example, is notorious for its interceptions of uncertified agricultural products at the state line. The rigid laws that prohibit private citizens from bringing a bag of oranges into southern California are generally given credit for excluding numerous pest species that might have caused millions of dollars in losses. The price tag for these prevention efforts is only a fraction of the estimated $350 million Californians spent to clean up their most recent infestation of the Mediterranean fruit fly ( Ceratitis capitata ). • Federal import/export laws have been enacted to establish standards for a wide range of agricultural products. Most of the fruits and vegetables imported to the U.S., for example, must receive some form of fumigation, heat treatment, controlled atmosphere storage, or radiation exposure before they are released from quarantine. These post-harvest treatments are designed to kill whatever pest species may be present without affecting taste or quality of the produce Plant Quarantine in Europe: • European and Mediterranean Plant Protection Organization (EPPO): An inter-governmental organization responsible for European cooperation in plant protection and plant health in the European and Mediterranean region. • Under the International Plant Protection Convention (IPPC), EPPO is the regional plant protection organization (RPPO) for Europe. Founded in 1951 by 15 European countries, EPPO now has 50 members, covering almost all countries of the European and Mediterranean region. • Its objectives are to protect plants, to develop international strategies against the introduction and spread of dangerous pests and to promote safe and effective control methods. • As a Regional Plant Protection Organization, EPPO also participates in global discussions on plant health organized by FAO and the IPPC Secretariat. One of the aims of EPPO is to help its member countries to prevent entry or spread of dangerous pests (plant quarantine). • The Organization has therefore been given the task of identifying pests which may present a risk, and of making proposals on the phytosanitary measures which can be taken. In recent years, the identification of risk has been formalized, because transparent justifications of phytosanitary measures are required and phytosanitary measures have to be commensurate with the risk. • Several EPPO Standards on Pest Risk Analysis (PRA) are now available. To perform these activities, much information on pests presenting a risk to the EPPO region is required and has been collected by the Organization. IPPC (International Plant Protection Convention): • The International Plant Protection Convention (IPPC) is an international plant health agreement, established in 1952, that aims to protect cultivated and wild plants by preventing the introduction and spread of pests. • The 172 signatories (as of 30 November 2009) adhere to the Convention. Countries that wish to become contracting parties to the IPPC must deposit their instrument of adherence with the Director General of FAO. • IPPC’s core activities include: governance, standards setting, information exchange, dispute settlement, capacity building and reviewing the global status of plant protection. • ISPMs (International Standards for Phytosanitary Measures) are the standards, guidelines and recommendations recognized as the basis for phytosanitary measures applied by Members of the World Trade Organization under the Agreement on the Application of Sanitary and Phytosanitary Measures (the SPS Agreement). ISPMs are adopted by contracting parties to the IPPC through the

Commission of Phytosanitary Measures (CPM).

The legislative measures in force now in different countries can be grouped into three classes . They are: • International Quarantine : Legislation to prevent the introduction of new pests, diseases and weeds from foreign countries. • Domestic quarantine : Legislation to prevent the spread of already established pests, diseases and weeds from one part of country to another (state to state, region to region, district to district etc.) • Legislation to enforce upon the farmers regarding the application of effective control measures to prevent damage by already established pests. International Quarantine: • The National Plant Quarantine Station (NPQS) at Rangpuri, New Delhi and four Regional Plant Quarantine Stations (RPQS) at Amritsar, Chennai, Kolkata and Mumbai are the major stations and are located at places having international airport/seaport/land frontier with neighboring countries. • There are 35 Plant quarantine Stations at different Airports, Seaports and Land frontiers implementing the Plant Quarantine regulations. • National Bureau of Plant Genetic Resources (NBPGR), New Delhi which is the nodal institution for exchange of plant genetic resources has been empowered under PQ order to handle quarantine processing of germ plasm and transgenic planting material being imported for research purposes in the country. Keeping in view the bio-safety concerns associated with the growing of imported transgenic material, a containment facility has been established at NBPGR, New Delhi for their quarantine processing. • As per the recent amendments made under the PQ order, the Advanced Centre for Plant Virology at IARI, New Delhi, Indian Institute of Horticultural Research (IIHR), Bangalore and Institute of Himalayan Bioresource Technology, Palampur have been identified for ensuring virus-free status in the imported in vitro material. • Refer Plant Quarantine Order 2003 (http://www.plantquarantineindia.org ) for all the details for the import requirements for various products from different countries. Domestic Quarantine: • Under the DIP Act, there is a provision of Domestic Quarantine to restrict the interstate movement of nine invasive pests viz flute scale (cottony cushiony scale), sanjose scale, coffee berry borer, codling moth, banana bunchy top and mosaic viruses, potato cyst nematode, potato wart and apple scab. • Under these provisions, Madras Govt., enacted Madras Agricultural Pests and Diseases Act in 1919, and it was the first state to enact such laws in the country. This act was passes to prevent the spread of insect pests, disease and weeds from other states, and also from one district to another. Eg: Fluted Scale (Cottony cushiony scale-Icerya purchasii ) was localized in Nilgiris and Kodaikanal areas, and hence none of its alternate hosts were permitted to get transported from these areas. Quarantine station was opened at Mettupalyam and Gudulur of Nilgiris, and at Shenbeganur & Hill Station of Kadikanal in 1943, and were closed subsequently. Legislation to enforce the application of effective control measures: • Under the States Pests Act, the farmers were asked to remove and destroy coconut leaflets infested with black headed cater pillar Opisina arenosella around Mangalore in 1923, and in 1927 in Krishna and Guntur Dists. Later the act was withdrawn, after its effective control with use of biological control agents.

Quarantine Period of Isolation (40 Days) of people and animals is usually followed to prevent entry, establishment and spread of diseases. 71

Lecture: 13 Biological control-types of biological control-introduction-augumentation and conservation- parasite-parasitoid-parasitism-grouping of parasites based on nature of host, stage of host, site of parasitization, duration of parasitization, degree of parasitization & food habits-number of hosts attacked-kinds of parasitism-qualities/attributes of an effective parasite to be successful biological agent.

BIOLOGICAL CONTROL:

• Destruction or regulation or suppression of undesirable insects, other animals or plants by the introduction, encouragement or artificial release of their natural enemies is called biological control. • Biological Control is defined as the reduction of pest populations by natural enemies and typically involves an active human role. • Biological control of pests in agriculture is a method of controlling pests (including insects, mites, weeds and plant diseases) that relies on predation, parasitism, herbivory, or other natural mechanisms. It can be an important component of integrated pest management (IPM) programs. • Biological suppression involves the action of parasitoids, predators or pathogens in maintaining another organism's population density at lower average than would occur in their absence. It includes the use of natural or modified organisms, genes, gene products etc., to reduce the effects of undesirable organisms (pests), so as to favor desirable organisms such as crops, trees, animals, beneficial insects and microorganisms. • Project Directorate of Biological Control of Crop Pests (PDBC) of ICAR and CIBC (Commonwealth Institute of Biological Control-1957) located at Bangalore. Then, PDBC was changed to National Bureau of Agriculturally Important Insects (NBAII) during 1993 to undertake basic and applied research on biological control of crop pests and weeds. The Bureau is also providing the technological backstop for establishment of biological control agent’s production centers to government and private entrepreneurs.

Agents of Biological Control

Parasitic Insects

Predatory Insects

Pathogens (Micro -organisms)

Ba cteria

Virus

Fungi

Nematodes

There are three basic types of biological control strategies:

Conservation: A variety of management activities can be used to optimize the survival and/or effectiveness of natural enemies. Conservation activities might include reducing or eliminating insecticide applications to avoid killing natural enemies, staggering harvest dates in adjacent fields or rows to insure a constant supply of hosts (prey), or providing shelter, over-wintering sites, or alternative food sources to improve survival of beneficial species. Classical Biological Control: It is the introduction of natural enemies to a new locale where they did not originate or do not occur naturally . This is usually done by government authorities. In many instances the complex of natural enemies associated with an insect pest may be inadequate. This is especially evident when an insect pest is accidentally introduced into a new geographic area without its associated natural enemies. These introduced pests are referred to as exotic pests and comprise about 40% of the insect pests in the United States. For example, to obtain the needed natural enemies, scientists turned to classical biological control through the introduction of beetle Zygogramma from Australia for the control of exotic weed Parthenium which is native of Australia. This is the practice of importing, and releasing for establishment, natural enemies to control an introduced (exotic) pest , although it is also practiced against native insect pests. The first step in the process is to determine the origin of the introduced pest and then collect appropriate natural enemies associated with the pest or closely related species. The natural enemy is then passed through a rigorous quarantine process, to ensure that no unwanted organisms (such as hyperparasitoids) are introduced, and then they are mass produced, and released . Follow- up studies are conducted to determine if the natural enemy becomes successfully established at the site of release, and to assess the long-term benefit of its presence. The steps include exploration, quarantine tests, importation, mass production, and release, follow-up. Augmentation: Natural enemies that are unable to survive and/or persist in a new environment can sometimes be reared in large numbers and periodically released to suppress a pest population. In some cases, small numbers of a beneficial species are released in several critical locations to suppress local pest outbreaks (an inoculative release ). In other cases, larger numbers are released in a single location to flood the pest population with natural enemies (an inundative release ).

PARASITES: • Parasite is one, which attaches itself to the body of the other organism, either externally or internally, and gets nourishment and shelter, at least for shorter duration or for the entire life-cycle . • The organism which is attacked by the parasites is called host . • The phenomenon of obtaining nourishment at the expense of the host to which parasite is attached is called parasitism. • A parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism, which it ultimately kills (and often consumes) in the process. Thus they are similar to typical parasites except in the certain fate of the host. In a typical parasitic relationship, the parasite and host live side by side without lethal damage to the host. Typically, the parasite takes enough nutrients to thrive without preventing the host from reproducing. Parasitoids kill their hosts; parasites (such as lice and fleas) do not. In a parasitoid relationship, the host is killed, normally before it can produce offspring. A parasitoid is an insect that kills (parasitises) it’s host-usually another insect-in order to complete its lifecycle. Parasitoids are also often closely coevolved with their hosts. Most biologists use the term parasitoid to refer only to insects with this type of life history. The term parasitoid was coined in 1913 by the German writer O. M. Reuter to describe the strategy in which, during its development, the parasite lives in or on the body of a single host individual, eventually killing that host, the adult parasitoid being free-living. • Most insect parasitoids are wasps or flies . • Parasitiods comprise a diverse range of insects that lay their egg on or in the body of an insect host, which is then used as a food for developing larvae. • Parasitic wasps take much longer than predators to consume their victims, for if the larvae were to eat too fast they would run out of food before they became adults. Such parasites are very useful in the organic garden, for they are very efficient hunters, always at work searching for pest invaders. As adults they require high energy fuel as they fly from place to place, and feed upon nectar, pollen and sap, thereby pollinating plenty of flowering plants, particularly buckwheat, umbellifers, and composites will encourage their presence.

Parasites can be grouped / classified based on:

Host Zoophagous parasites That attack animals Cattle pests Phytophagous parasites That attack plants Crop Pests Entomophagous That attack insects Parasites parasites Site of Parasitisation Ecto-parasites This attacks its host from outside of the Head louse: Epiricania body of the host. The mother parasite lays melanolenca, its eggs on the body of the host and after Epipyrops spp. on sugarcane the eggs are hatched, the larvae feed on fly the host by remaining outside only. Endo-parasites This enters the body of the host and feeds Braconoids & from inside. The mother parasite either Ichnemonoids lays its eggs inside the tissues of the host Apanteles flavipes on jowar or on the food materials of the host to stem borer

gain entry inside

Stage of the Host Egg parasite Attacks egg stage of the host Trichogramma spp. Early larval parasite Attacks early larval stage Apanteles spp. Mid larval p arasite Attacks mid larval stage Bracon hebetor Late larval parasite Attacks late larval stage Gonozus nephantidis Pre-pupal parasite Attacks pre-pupal stage Elasmus nephantidis Pupal parasite Attacks pupal stage Tetrastichus Israeli Trichospilus pupivora Stomatocerus spp. Duration of the attack Transitory parasite It is not a permanent parasite (completing Braconoids and all stages of its life cycle on the same Ichneumonoids host), but transitory which spends few stages of its life cycle in one host and other stages on some other species of hosts, or as free living organism Permanent Parasite Which spends all the stages of its life Head louse cycles on the same host Degree of parasitisation Obligatory parasite Parasite which can live only as a parasite Bird lice and Head louse and cannot live away from the host even for short period Facultative parasite Parasite, which can live away from the Fleas host at least for shorter period Food Habits Monophagous Which has only one host spp and cannot Gonizus nephantidis on (Host-Specific) survive in another spp Opisina arenosella Oligophagous Which has very few hosts (more than one Isotoma javensis on spp.) and hosts are closely related sugarcane, sorghum borers Ployphagous Which has number of widely different Bracon spp. Apanteles Spp. host species on lepidopteran caterpillars Number of Hosts requires for completion of life cycle Monocious parasite Requires only one host for the completion of life cycle (development) Heterocious parasites Requires several different hosts for the completion of life cycle (development)

Kinds of Parasitism: • Simple parasitism: Irrespective of number of eggs laid, the parasite attacks the host only once. Apanteles taragame on the larvae of Opisina arenosella; Gonizus nephatidis on the larvae of Opisina arenosella . • Super parasitism: A host has multiple attacks from parasites of the same species. Many individuals of the same species of parasite attack a single host. Apanteles glomeratus on Pieris brassicae, Trichospilus pupivora on Opisina arenosella. • Multiple parasitism: When more than one species of the parasite attckes the same host simultaneously. Eggs of Scirpophaga incertulas are attacked by Trichogramma spp. Telenomus Spp. and Tetrastichus spp. HOST IS ONLY ONE, IN ALL ABOVE CASES. • Hyper parasitism: When the parasite itself is attacked by another parasite. Gonozus nephantidis is parasitised by Tetrastichus israeli . Most of the braconids and Bethylids

are hyper-parasites. 75

• Primary parasite: A parasite attacking an insect pest-is not a parasite, and beneficial to mankind. • Secondary parasite: A hyper-parasite attacking a primary parasite-is harmful to mankind, because is attacking the beneficial primary parasite. • Tertiary parasite: A hyper-parasite attacking a secondary parasite-is beneficial to man. • Quaternary parasite: A hyper-parasite attacking the tertiary parasite-is harmful to man.

Most of the insect parasites are useful due to effect on harmful insects’ pests, but if a parasite attacks productive/beneficial insects like silkworm, lac insect, honey bees, pollinators, the parasites are harmful to mankind.

Qualities of successful parasite in biological control programmes: The parasite • Should be adoptable to environmental conditions in the new locality • Should be able to survive in all habitats of the host • Should be species-specific • Should be able to multiply faster than the host • Should have more fecundity • Life cycle should be shorter than host • Should have high sex ratio • Should have good searching capability for host • Should be amenable for multiplication in labs • Should bring down host population in 3 months • Should have quick dispersal capability • Should be free from hyperparasites • Should not be the parasite on productive insects

Four of the most important groups are: Trichigramma wasps (Hymenoprera): Egg parasitoids Ichneumonid wasps (Hymenoptera) : (5–10 mm). Parasites mainly on caterpillars of butterflies and moths Braconid wasps (Hymenoptera) : Tiny wasps (up to 5 mm) attack caterpillars and a wide range of other insects including greenfly. Chalcid wasps (Hymenoptera) : Among the smallest of insects (<3 mm). Parasitize eggs/larvae of greenfly, whitefly, cabbage caterpillars and scale insect. Tachinid flies (Diptera) : Parasitize a wide range of insects including caterpillars, adult and larval beetles, true bugs, and others. • About 10% of described insect species are parasitoids. • There are four insect orders that are particularly renowned for this type of life history . By far, the majority are in the order Hymenoptera . The largest subgroups of these are the chalcidoid wasps (Chalcidae) and the ichneumon wasps (Ichneumonidae). The flies (order Diptera ) include several families of parasitoids, the largest of which is the family Tachinidae. The other two orders include strepsiptera and some beetles of coleoptera . • Adult parasitoids feed on sugars , including those found in flower nectar and aphid honeydew. Adult parasitoids with access to these sugary food sources generally live

longer and the females will lay more eggs, this allows them to parasitise more hosts. Some adult parasitoids also 'host feed'. This involves feeding on fluids that exude from 76

a host's puncture wound, caused by the wasp's ovipositor ('stinger'). Host feeding supplements the nutrition of the adult parasitoid, and odours detected while host feeding may assist the wasp with host searching. Female Trichogramma, Netelia and Ichneumon wasps host feed

Successful examples: 1. Apple wooly aphid ( Eriosoma langerum ) in Cooner area in TN was successfully controlled by Aphelinus mali (adult endoparasitoid) during 1940. 2. Coconut black headed caterpillar Opisina arenosella was successfully controlled using potential parasitoids (TABGET) parasitizing various stated of the pest. This is still in use in certain parts of Godavari districts, and other parts of TN and Kerala. Egg parasitoid Trichogramma australicum Early larval parasitoid Apanteles taragame Mid Larval parasitoid Bracon hebetor Late Larval Parasitoid Goniozus nephantidis Pre Pupal Parasitoid Elasmus nephantidis Pupal Parasitoid Trichospilus pupivora 3. Control of shoot borers of sugarcane, stem borers of paddy and sorghum with egg parasitoid Trichogramma australicum @ 50,000/acre/week for 4-5 weeks from one moth after transplanting. 4. Cotton pink bollworm ( Pectinophora gossypiella ) can be successfully controlled by Trichogramma chilonis @20,000/acre/week from flowering to boll formation. 5. Against Helicoverpa armigera on cotton, release of Trichogramma chilonis @ 50,000/acre/week for 4 weeks from 30-40 DAS gave good results. 6. Sugarcane top shoot borer ( Triporyza nivella ) can be controlled successfully releasing larval parasitoid Isotoma javensis. 7. Castor semilooper Achaea janata naturally controlled by larval parasitoid Microplitis ophiusae.

The most important parasitoids used and exploited for IPM programs are:

EGG PARASITOIDS: (Trichogramma spp, Telenomus spp. ) • Egg parasitoids kill their hosts before they hatch from egg, thus preventing crop damage by emerging caterpillars. • Egg parasitoids are difficult to see because of their small size . • The best way to find and identify them is to collect brown Helicoverpa eggs and store them in a clear container. If parasitised, these eggs will turn black and adult wasps will emerge in about 10 days. Unparasitised eggs will produce Helicoverpa larvae. • Trichogramma and Telenomus wasps are minute wasps (shorter than 1 mm) that parasitise Helicoverpa eggs are active in most summer crops, particularly sorghum, maize and cotton. • Egg parasitoids are very rare in chickpea crops . Trichogramma spp Telenomus spp Trichogramma wasp is yellow-brown with red eyes. Telenomus wasp is black with black eyes. 2-4 Trichogramma wasps develop within one egg of Only one Telenomus wasp develop within Helicoverpa spp . one egg of Helicoverpa spp. Numbers increase from low densities in spring to Numbers are most abundant in spring and become very abundant in late summer. early summer Trichogramma uses its antennae to measure the size of -- the host egg in order to determine the number of eggs it will lay in it.

For both species, it will take about 10 days at 25 oC for an adult wasp to emerge from a parasitised egg. 77

Trichogramma chilonis egg parasite of sugarcane internode borer ( Sacchariphagus indicus ), cotton boll worm ( Heliothis armigera) , and rice leaf folder (Cnaphalocrocis medinalis ) and over 200 insect pests Trichogramma japonicum egg parasite of rice stem borer ( Scirpophaga incertulas ) Telenomus rowani egg parasite of rice stem borer Telenomus remus Egg parasite of tobacco caterpillar ( Spodoptera litura )

Trichogramma chilonis • Egg parasite of over 200 insect pests • Females lay their eggs within the insect eggs • Completes the larval and pupal stages within the insect eggs • Total destruction of insect eggs and emergence of Trichogramm a adults from the eggs • Multiplication of Trichogramma and simultaneously pest management through egg • destruction • One Trichogramma adult can parasitize 90-100 eggs Field application of Trichogramma • Mass multiplication of Trichogramma on host eggs (Rice moth eggs) • One Trichocard contains 20000 parasitized eggs • Rate of application–40000 adults/acre i.e. 2 trichocards/acre • 3-4 releases at 12-15 days interval after irrigating the field • Avoid insecticidal spray after releasing Trichogramma in the fields Examples for field releases: Sugarcane early shoot borer T. chilonis sugarcane strain 4-6 releases @ 50,000/ha, at 10 days Chilo infuscatellus interval from 45DAP or appearance of pest Cotton boll worms ( Heliothis, T. chilonis or T. achaeae cotton strain 6 releases @ 1,50,000/ ha, Pectinophora, Earias) at weekly intervals from 45DAS or appearance of the pest Tomato fruit borer T. brasiliens 6 releases @ 50,000/ha, at weekly interval from Heliothis armigera 45DAT or appearance of the pest Paddy stem borer T. japonicum 6 releases @ 50,000/ha, at weekly interval from Scirpophaga incertulas 30DAT Maize stem borer T. chilonis 4-6 releases @ 75,000/ha, at weekly interval from Chilo partellus 45DAS or appearance of pest

EGG-LARVAL PARASITOID: The adults’ lays eggs on eggs of host, and the adults emerge from larvae of the host, thus killing the host at larval stage. Chelonis blackburni (braconidae) on cotton spotted boll worm ( Earias vitella )

LALVAL PARASITOID : The adults lays eggs on larvae, and the youngone/larvae of parasitoid develops inside the larvae of host, and adult emerge from host larvae, thus killing the larvae of host.

Eg: Microplitis spp, Bracon spp. Cotesia spp. (Apanteles spp.)

Bracon hebetor on the larvae of Opisina arenosella Bracon brevicornis on the larvae of Opisina arenosella Campoletis chloridae (Ichni) on the larvae of Heliothis armigera Microplitis demolitor on the larvae of Heliothis armigera Goniozus nephantidis on the larvae of Opisina arenosella Cotesia plutella on the larvae of Plutella xylostella Cotesia glomerata on the larvae of Pieris brassicae

Helicoverpa caterpillars are parasitised by several small to medium-sized wasps and a group of specialised flies (tachinids). There are a number of wasps those parasitise Helicoverpa larvae. Only the Microplitis spp. thought to be most important for pest management. Microplitis demolitor : Microplitis is a small (3 mm) black wasp with an orange abdomen and black wings. Encountered in all summer field crops, Microplitis is particularly abundant in sorghum and cotton. Another way to find Microplitis is to look for its fawn-coloured cocoon attached to dying Helicoverpa caterpillars. Microplitis only attacks Helicoverpa . Female Microplitis wasps sting second instar (4-7 mm) Helicoverpa caterpillars. The parasitoid larva then feeds internally and chews a hole in the side of its host to emerge and pupate externally. Host caterpillars are killed before they do much feeding damage. The whole Microplitis lifecycle (egg-adult) takes about 10-12 days.

Bracon hebetor is a minute Braconidae wasp (Hymenoptera) that is an internal parasite to the caterpillar stage of Plodia interpunctella , the Indian meal moth , in the late larval stage of the mediterranian flour moth and the almond moth (mainly lepidopterans of stored grain pests).

Cotesia (Apanteles) glomerata (Braconidae:Hymenoptera) is not available commercially. The main habitat is cole crops attacking cabbage white butterfly Pieris brassicae and its relatives. Cotesia adults are small (about 7 mm), dark wasps and resemble flying ants or tiny flies. The abdomen of the female narrows to a downward curving extension called the ovipositor with which she lays eggs. The pupae are in an irregular mass of yellow silken cocoons attached to the host larva or to plant leaves. Coteasia (Apanteles) spp is naturally occurring parasitoid on citrus butterfly larva ( Papilio spp)

LARVAL-PUPAL PARASITOID: The adult parasitoid lays eggs in larvae, and the young one develops inside larvae, adult parasitoid emerge from host pupa, thus killing host insect.

Isotoma javensis on pre-pupal stage of sugarcane top shoot borer ( Scirpophaga excerptalis) Heteropelma scaposum on Helicoverpa armigera Gnonotoma micromorpha on leaf minor Liriomyza trifolii Tetrastichus giffardianus oviposits into mature host larvae of fruit fly Bactrocera spp , and the adults emerge from young pupae after the puparium is formed Heteropelma stings caterpillars at 3 rd instar stage and older. After being parasitised, the host caterpillar continues growing and pupates in the soil as normal. However, shortly after pupation, parasitoid feeding kills the host. When the Heteropelma larva is fully developed, it pupates within the helicoverpa pupal case. The adult wasp emerges by chewing open the pupal case and exits the pupal chamber by crawling up the emergence tunnel.

PUPAL PARASITOID: The adult parasitoid lays eggs on host pupa, and completes life cycle within host pupa, and adult emerge from host pupa, thus killing the host insect.

Tetrastichus Israeli on pupa of Opisina arenosella Brachymeria nephantidis on pupa of Opisina arenosella Ichneumon promissorius On pupa of Heliothis Tetrastichus brontispae on pupa of fruit fly Bactrocera spp Xanthopimpla stemmator on pupa of corn borer in maize stem

Nymphal and Adult parasitoids: Encarcia Formosa on cotton whitefly ( Bemisia tabaci ) Aphelinus mali on aphids Epiricania melanoleuca on sugarcane leaf hopper Pyrilla perpusilla DIPTERAN PARASITOIDS: Mainly belongs to tachinidae family parasiting on larval and pupal stages of some lepidopterans. (Eg: Eucelatoria bryani on larvae of Helicoverpa armigera ).

MASS MULTIPLICATION TECHNIQUE FOR Trichogramma spp egg parasitoids: Trichogramma is mass multiplied on eggs of host insect Corcyra cephalonica i.e. Rice moth Mass multiplication / rearing of Corcyra cephalonica Procure sorghum (bold white grains) grains not treated with any insecticide. The grains are broken into 3-4 pieces and heat sterilized in an oven at 100 oC for 30 minutes. The broken sorghum grains are sprayed with 0.1% formalin to prevent mould development and increase the grain moisture to optimum (15-16%) which is lost due to heat sterilization. Air dry the material and pour 2.5 kg of sorghum grains per box. Add 300cc of Corcyra eggs per box and secure the lid for 30 days, from 40 th day onwards the adult moths start emerging. The moths are collected daily and transferred to oviposition cages for egg collection. The eggs that are collected are treated with UV rays (30w UV tube, or 45 minutes at a distance to 2 feet) to prevent hatching Preparation of Tricho cards The eggs that are inactivated by exposure to UV rays are glued to Tricho cards of 15 x 10 cm which is prepunched to obtain 16 pieces of 4 x 3 cm leaving uncovered space at one end to facilitate stapling. In glass vials, the eggs are exposed to adult female Trichogramma in the ratio of 20: 1 for 24hrs. In case cards exposed in polythene bags, the egg; adult female ratio is 30:1 and the females are allowed to parasitise till they die. After parasitization, 6 day old parasitized egg cards are prepared for shipment/release . In case of shipment, strips of wood wool coated with concentrated and dried honey is placed inside the box. The adults start emerging 8 days after parasitisation. In the field, Tricho cards are stapled to the leaves/plant parts Precautions • Tricho cards should be packed, keeping parasitized surface on inner surface. • Emergence date should be specified on the cards. • Cut pieces if Tricho cards should be stapled in morning hours and inner side of the leaf to avoid direct sunlight.

MASS MULTIPLICATION TECHNIQUE FOR Bracon hebetor (Braconidae: Hymenoptera) , a polyphagous endo-larval parasitoid

The larval parasitoids Bracon hebetor parasitizages the larvae of many lepidopterous pests. Mass rearing can be done on the full grown larvae of Corcyra cephalonica . Both male and female adult parasitoids are released in a cage for mating. After mating, males are set apart and females (identified with their ovipositor) are released in a vial containing 4th and 5 th instar larvae of Sesamia inferens (Ragi pink borer) or Corcyra cephalonica. The parasitoid paralyses the host larvae before oviposition. The eggs are laid by the parasitoid in the inter segmental region of the larvae. The incubation period is 24-36 hrs. The hatched 1st instar parasitoid larvae feed on the internal content of Sesamia inferens or Corcyra cephalonica till pupation that takes place outside the host larvae as cocoons. These cocoons are collected and kept in adult cages for adult emergence. Diluted honey is provided as diet for the adults.

Bracon chinensis a gregarious ecto-larval parasitoid Bracon chinensis is gregarious ecto larval parasitoid of graminaceous borers. For mass multiplication in the laboratory, the adults (both male and female) of Corcyra cephalonica are released into a wide mouthed bottle with open end at both sides. These sides are covered with muslin cloth held in position by rubber band. Diluted honey is provided as food for the parasitoid adults. For parasitisation, host larva are arranged above the layer of muslin cloth at both sides of the bottle and covered by another layer of cloth. The host larvae are thus placed in between the two layers of muslin cloth. The female parasitoid paralyses the host larvae and start ovipositing the eggs near or on the body of the larva. After 2 days, the paralysed host larvae, along with eggs and larvae of parasitoid are transferred to grooved ridges of blotting paper arranged in plastic soap boxes. The parasitoid larvae feed externally on the host larvae, completes its life cycle and pupates in cocoons. These parasitoid cocoons are collected and placed in adult cages for emergence with honey solution as food.

Lecture : 14 Biological control-predators-predatism-qualities of insect predator-differences between predator and a parasite-mass multiplication of important insect parasitoids (Trichigramma, Bracon, Tetrastichus) and predators (Chrysoperla, Cryptolaemus, Cheilomenes).

PREDATORS • A predator is one which catches and devours smaller or more helpless creatures by killing them in single meal . A predator that lives by preying on other organisms. A predator is one that victimizes, plunders, or destroys, especially for one's own gain. A predator is an animal that lives by capturing and eating other animals. • Insect killed by is called prey while insect which kills is called predator .

Predatism: Based on the degree of usefulness to man, predators are classified as: 1. Entirely predatory: Eg: Ant lions (lace wings), tiger beetles, lady bird beetles except brinjal ladybird beetles ( Henosepilachna spp. ) 2. Mainly predatory, but occasionally harmful: Eg. Odonata (Dragon flies) and Mantids, occasionally attack honeybess 3. Mainly harmful but partly predatory: Eg: Cockroach feeds on termites, Adult blister beetles feeds on flowers, but grubs predate on hopper eggs. 4. Mainly scavenging and partly predatory: Eg: Earwigs feed on decaying organic matter and also predate on fly maggots, both ways, they are helpful. 5. Variable feeding habits of predator: Tettigonidae (Omnovorous and Cornovorous), but damage crops by laying eggs. 6. Stinging predators: In this case, nests are constructed and stocked with prey, which have been stinging and paralyzing the mother insect on which eggs are laid and then sealed up. Larvae emerging from egg feed on the paralyzed but not yet died prey. Eg: Spider Wasps and Wasps.

Insect Predator: It is defined as the one, which is Large in size, active in habits, capacity for swift movements, structural adaptations with well-developed sense organs to catch prey, many remain stationary and sedentary, suddenly seize the prey when it comes to its reach, feed upon large number of small insects every day, may have cryptic coloration and develops markings. Eg: preying mantids, robber flies.

Qualities of insect predator: • Narrow host range: Generalized predators may be good natural enemies but they don't kill enough pests when other types of prey are also available. • Climatic adaptability : Natural enemies must be able to survive the extremes of temperature and humidity that they will encounter in the new habitat. • Synchrony with host (prey) life cycle : The predator should be present when the pest first emerges or appears. • High reproductive potential : Good biocontrol agents produce large numbers of offspring. • Efficient search ability : In order to survive, effective natural enemies must be able to locate their host or prey even when it is scarce. In general, better search ability results in lower pest population densities. • Short handling time : Natural enemies that consume prey rapidly or lay eggs quickly

have more time to locate and attack other members of the pest population. 82

• Survival at low host (prey) density : If a natural enemy is too efficient, it may eliminate its own food supply and then starve to death. The most effective biocontrol agents reduce a pest population below its economic threshold and then maintain it at this lower equilibrium level. • Efficient eating ability : They should kill or consume much prey. • All should be predatory : Males, females, immatures, and adults may be predatory • Should prey on all host stages : They attack immature and adult prey

Differences between predators and parasites:

Character Predator Parasite Host range Mostly generalized feeder except Exhibits host-specificity & in lady bird beetles and hover flies many cases, range of host species which show some specificity to prey attacked is very much limited Activity Very active in habitats Usually sluggish, once the host is secured Development of Organs of Locomotion, Sense Not very well developed and Organs organs and Mouth parts are well sometimes reduced even. developed Ovipositor is well developed and oviposition specialized Body size Stronger, Larger Smaller Intelligence Usually more intelligent than the Not markedly more intelligent prey than host Habitat Habitat is independent that of prey Habitat and environment is determined by Host Life cycle Long Short Plan of attack Attack on prey is casual and not Planning is more evident well planned Speed of killing Seizes and devours the prey rapidly Lives in or on the body of the host killing slowly Purpose Attack on prey is for obtaining It is for provision of food for food for the predator itself, except the off-springs in wasps which sting the caterpillars to paralyze them and provide them as food in the nest for the young Number required A single predator may attack A parasite usually completes for development several preys in shorter period development in a single host in most cases.

Insect predators of Agricultural Importance:

Order and Family Scientific Name Prey COLEOPTERA Coccinella septumpunctata Aphids (Seven spotted Lady bird beetle) Coccinella rependa Aphids Scymnus coccivora Pseudococcus sp. Mealy bugs very specific mealy bug destroyer Coccinellidae Cheilomenus sexmaculata Mealy bugs, Scales (Laby Bird Rodolia cardinalis (Vadalia beetle) Icerya purchasi Beetles) Very specific to scales Cottony cushiony scale Chilocorus nigritus Tapioca scales Cryptolaemus montrouzieri Pseudococcus sp. (Mealy bug destroyer ) Mealy bugs Very specific to mealy bug Harmonia axyridis Aphids, scales, and Psyllids (multi-colored Asian lady beetle) Carabidae Parenta lacticincta Coconut black headed caterpillar (Ground beetle) Ophiomea spp. Rich BPH and Leaf folder Cicindellidae Cicindela spp. Soil dwelling insects (Tiger beetle) HEMIPTERA Reduviidae Rhinocoris fuscipes Helicoverpa armigera (Assasin Bugs) Platymeris laevicollis Coconut rhinoceros beetle (Oryctes rhinoceros) Miridae Cyrtorhinus lividipennis Rice BPH ( Nilaparvatha lugens ) (Mirid Bugs) Veliidae Microvelia atrolineata Rice GPB and GLH (Riffle Bugs) NEUROPTERA Chrysopidae Chrysoperla carnea Aphids, Scales, Bollworms, (Lace wings) (Green lace wing) Mealy bugs Myrmeliontidae Myrmelion spp. Ants and soil dwelling insects (Antlions) GENERAL PREDATORS Common name Stage of the Host insect / prey predator Dragon flies Naiads, adults Small insects, butterflies, Important predators of mosquitoes Damsel flies Naiads, adults Small insects, butterflies Preying mantids Nymphs, adults Grasshoppers, caterpillars, butterflies Giant water bug Adults Small aquatic insects Robber flies Adults Small aquatic insects Hover flies (Syrphids) Larva Aphids (Dipteran flies)

Wasps Adults, grubs Caterpillars Ants Adults, grubs Many insects

LADY BIRD BEETLES: ( Coccinellidae: Coleoptera) • Lady beetles, ladybugs, or ladybird beetles are among the most visible and best known beneficial predatory insects. • Most lady beetles, as both adults and larvae, feeding primarily on aphids. They also feed on mites, small insects, and insect eggs . Many crops benefit from lady beetles. They are helpful for growers of vegetables, grain crops, legumes, strawberries, and tree crops; however any crop that is attacked by aphids will benefit from these beetles. Most lady beetles found on crops and in gardens are aphid predators . Some species prefer only certain aphid species while others will attack many aphid species on a variety of crops. Some prefer mite or scale species . If aphids are scarce, lady beetle adults and larvae may feed on the eggs of moths and beetles, and mites, thrips, and other small insects , as well as pollen and nectar. They may also be cannibalistic. Because of their ability to survive on other prey when aphids are in short supply, lady beetles are particularly valuable natural enemies. • The two exceptions are the Epilachna dodecastigma and Epilachna vigintioctopunctata, a specialist herbivore of solanaceous plants (brinjal). The adults and larvae of both species feed on plants. These pests are also observed on cowpea in recent times in India. • Lady beetles are usually red or orange with black markings . Some lady beetles are black, often with red markings. Adult lady beetles are small, round to oval, and dome-shaped. The most well- known have black markings on red, orange, or yellow forewings, but some are black. The area immediately behind the head, the pronotum, may also have a distinctive pattern. The color and pattern of markings for each species may vary, but can aid identification. They have alligator-like larvae . • Female lady beetles may lay from 20-1,000 eggs over a 1- 3 month period. Eggs are usually deposited near prey such as aphids, often in small clusters in protected sites on leaves and stems. The eggs of many lady beetle species are small, cream, yellow, or orange, and spindle-shaped. They resemble those of Mexican bean beetle and Colorado potato beetle, but are usually smaller. • Lady beetle larvae are dark and alligator-like with three pairs of prominent legs . Depending on the species and availability of prey, larvae grow from less than 1 mm to about 1 cm in length, typically through four larval instars, over a 20 to 30 day period. Large larvae may travel up to 12 m in search of prey. The larvae of many species are

gray or black with yellow or orange bands or spots. • The last larval instar remains relatively inactive before attaching itself by the abdomen to a leaf or other surface to pupate . Pupae may be dark or yellow-orange. The pupal stage may last from three to 12 days depending on the temperature and species. The adults emerge, mate, and search for prey or prepare for hibernation, depending on the availability of prey and time of year. Adults may live for a few months to over a year. The more common species typically have one to two generations per year. • Lady beetles are voracious feeders and may be numerous where prey is plentiful and broad- spectrum insecticide use is limited. Lady beetles need to eat many aphids per day so that they can lay eggs. The convergent lady beetle may eat its weight in aphids every day as a larva and consume as many as 50 aphids per day as an adult . Seven spotted lady beetle adults may consume several hundred aphids per day and each larva eats 200 to 300 aphids as it grows. Once the adults and larvae have eliminated an aphid colony, they will search for additional food. • Lady beetles are effective predators if aphids are abundant (high pest density) but are thought to be less effective at low pest densities. There may also be some crop damage before lady beetles have an impact on an aphid population.

Coccinella Rodolia cardinalis (Vedalia septempunctata beetle): This was introduced in to (seven spotted ladybird USA for the control of cottony beetle): Most common in cushiony scale Icerya purchasi crops and has been reared on citrus. Most successful by some workers. predator and is very specific to scale

Cryptolaemus Harmonia axyridis (multi-colored montrousieri asian lady beetle): Native of (mealy bug destroyer): India, introduced to USA. This Most commercially preys upon many species of exploited predator on injurious soft-bodied insects such mealybug, small dark as aphids, scales, and psyllids. brown lady beetle with a orange tan on head

LACE WINGS : ( Chrysopidae: Nueroptera) • Common Green Lacewing ( Chrysoperla carnea ) or ( Chrysopa carnea ): These green lacewings are common in much of India. Adults feed only on nectar, pollen, and aphid honeydew, but their larvae are active predators . C. carnea occurs in a wide range of habitats and C. rufilabris may be more useful in areas where humidity tends to be high (greenhouses, irrigated crops). • Adult green lacewings are pale green, about 12-20 mm long, with long antennae and bright, golden eyes. They have large, transparent, pale green wings and a delicate body . Adults are active fliers, particularly during the evening and night and have a characteristic, fluttering flight. Oval shaped stalked eggs are laid singly at the end of long silken stalks and are pale green, turning gray in several days. The larvae, which are very active, are gray or brownish and alligator-like with well- developed legs and large pincers with which they suck the body fluids from prey . Larvae grow from <1 mm to 6-8 mm. • They are found in Cotton, sweet corn, potatoes, cole crops, tomatoes, peppers, eggplants, asparagus, leafy greens, apples, strawberries, and other crops infested by aphids. • Several species of aphids, spider mites (especially red mites), thrips, whiteflies, eggs of leafhoppers, moths, and leafminers, small caterpillars, beetle larvae, and the tobacco budworm are reported prey. They are considered an important predator of long-tailed mealybug in greenhouses and interior plantscapes.

HOVER FLIES (Syrphids, Syrphid flies): (Syrphidae : Diprera) • Syrphid flies, also known as hover flies for their ability to hover in flight, are common predators of aphids and other soft bodied insects . Adults are usually bee mimics. Hoverflies resemble slightly darker bees or wasps and they have characteristic hovering, darting flight patterns. • There are over 100 species of hoverfly whose larvae principally feed upon greenfly (aphids) , one larva devouring up to fifty a day, or 1000 in its lifetime. They also eat fruit tree spider mites and small caterpillars . Adults feed on nectar and pollen, which they require for egg production. Eggs are minute (1 mm), pale yellow white and laid singly near greenfly colonies. Larvae are 8–17 mm long, disguised to resemble bird droppings; they are legless and have no distinct head. Semi-

transparent in a range of colours from green, white, brown and black. Hoverflies can be encouraged growing attractant flowers like narigold, brinjal etc., 86

Successful examples: • Cottony cushiony scale ( Icerya purchasii ) pest on fruit trees was successfully controlled by its predatory beetle Rodolia cardinalis- specific to scales , in Nilgiris in TN. The predator was imported from California in 1929 and from Egypt in 1930, and is an example for classical biological control. The pest was controlled within a year. • Beetle Cryptolaenus montrouzieri controls mealybugs in brinjal ( Centrococcus insolitus ), psillid on guava and sapota ( Pulvinaris psidi ), mealybug in grapes ( Meconellicoccus hirsutus ) and citrus mealybugs ( Pseudococcus corymbatus ) when released @ 1000-1500 adults/acre. • Two releases of second instar larvae of Chrysoperla carnea @ 1lakh/ha at 75 and 90 DAS for Helicoverpa armigera in Cotton. • Chrysoperla carnea Predator of soft bodied insects like aphids, white flies, jassids, mealy bugs & scales, also consume eggs of caterpillar pests. Chrysopid larvae are released in the field @ 8000- 10000 larvae/acre to feed on soft bodied insects. • Cryptolaemus Montrouzieri-mealy bug destroyer: Predator of mealy bugs on citrus, grapes, and pomegranate. Besides feeding on mealy bugs, lay their eggs near the mealy bug colonies, Beetles feed on all stages of mealy bugs. Successful when released @ 1000-1500 adults/acre.

MASS PRODUCTION OF Chrysoperla carnea (Green lace wing) • Adult Chrysoprela (approximately 200 in numbers) are released into an oviposition cage measuring 75 x 30 x 30 cm. The sides of the cages are lined with smooth nylon wire mesh of 0 size (not preferred for egg laying) and sliding top cover is fitted with black cloth for depositing the eggs. • To prevent damage to the eggs the top is slide over a comb fitted on one side of the cage. • The adults are provided with protein diet ( Composition of protein diet; Water+50% Honey+Protinex mixture+Castor pollen). • The sliding top cover is replaced on alternate days starting from 5 th day onwards. The oviposition cage is kept for 30-35 days and the dead adults are removed every alternate day. • The eggs that are deposited on the black cloth of sliding top cover of oviposition cage. • These eggs are kept on the black cloth for 24 hrs to facilitate hardening of the chorion and later dislodged by gently rubbing with piece of sponge. • The eggs that are collected are used for larval rearing. • In the first step, 3 days old chrysopid eggs (Approximately 120 in number) are mixed with 1.0 cc of inactivated (by exposure to UV rays) Corcyra eggs in plastic containers. On hatching the Chrysoperla larva start feeding on eggs of Corcyra . • On 3 rd day the Chrysoperla larva are transferred to 2.5 cm cubic cells of plastic louvers for individual rearing ( to prevent cannibalism). The larvae continue to feed on Corcyra eggs till pupation (Cocoon formation). • The total amount of Corcyra eggs required for 100 Chrysopid larvae is 5.0 cc. • Cocoons are collected after 24 hrs of formation and are placed in the oviposition cages for adult emergence and egg laying.

• The eggs that are laid can be used for field release or used for further culturing. 87

• For field release viable eggs are mixed with Corcyra eggs, saw dust and paper strips before shipment. Precautions: • Chrysopid eggs are packed in container with saw dust and paper strips in order to reduce the contact and cannibalism • Releases should be made early in the morning • Don not release them as eggs as they can be eaten by other predators • Do not use pesticides in the field where the predators are released.

MASS PRODUCTION OF Cryptolaemus montrouzieri: The host insect for multiplication of Cryptolaemus is mealybugs Production procedure for mealybugs: • Planococcus citri, P. lilacinus, Mecanellicoccus hirsutus, Ferrisia virgata are amenable for easy laboratory multiplication. • Pumpkins with ridges, furrows along with stalk have to be selected. • They are thoroughly washed with tap water to remove the dirt and dipped in 0.1 % benomyl or Carbendazim to kill any surface fungal pathogen. • Any pumpkin showing the symptoms of rotting should be discarded. • The cleaned pumpkins are shade dried and are infested with mealybug crawlers. If crawlers are not available ovisacs are placed over the pumpkin. • Each infested pumpkin is placed in 30 cm 3 wooden cage with muslin cloth covering. • The mealybugs mature and multiply after 30-35 days. Production procedure for Cryptolaemus montrouzieri • Pumpkin with mealybugs (15 days after infestation), are exposed to set of 100 Cryptolaemus beetles for 24 hrs • The beetles during this period feed on mealybugs & deposit eggs singly/group of 4-12. • After hatching, the grubs of Cryptolaemus feed on small mealybugs but as they grow they become voracious and feed on all stages of mealybugs till pupation. • For facilitating the pupation, dried guava leaves or paper pieces are kept in the cage on which the grubs of Cryptolaemus pupate. • The first beetle from the cage starts emerging on 30 th day of exposure to Cryptolaemus montrouzieri adults • The beetles are collected and kept in separate cages for about 10-15 days to facilitate the completion of mating and pre-oviposition. The beetles are provided with honey agar medium • The emergence of beetle is completed in 10 days

MASS PROCUTION OF Cheilomenes sexmaculata • Cheilomenes sexmaculata is a very important, polyphagous predator of aphids and other soft bodied insects. • The initial culture is started by collecting unparasitised pupae of Cheilomenes sexmaculata from the field. • Healthy pupae are bright yellow in color with black markings. • The freshly emerged adults are provided with Aphis craccivora (on cowpea seedlings) for 10 days during the period mating may occur. • Ten days old, pre-fed beetles are released on pumpkins with colonies of 25 days old Ferrisia virgata (Guava mealybug).

• The beetles are allowed to feed on F. virgata in the same cage for 25 days. 88

• Honey 50% in cotton swab is provided as additional food source for the beetles. • Dry leaves are provided on the side walls to facilitate the site of oviposition. • Yellow colored eggs are deposited in groups vertically on the dry leaves that are collected and used for further multiplication. • Eggs that are collected are kept in separate glass vial as the grubs are highly cannibalistic. • The grubs that hatch are released on cowpea seedlings infested with Aphis craccivora in plastic cups or glass jars. • During the process, 25 grubs of coccinellids can be reared for 8-9 days with 6500 aphids up to pupation.

Lecture: 15 Microbial control-bacteria, viruses, fungi and protozoa-important species of micro-organisms against major pests for incorporation in IPM-mass multiplication of Metarrhizium, Nomureae, Beauveria and Nuclear polyhedrosis virus (NPV).

Microbial Control: Insects are known since long ages to become infected with different entomopathogenic microorganisms that form an important factor of the natural mortality. Thus, they could play a distinct role in the collapse of an insect population under certain conditions. This phenomenon inspired Bassi to propose the idea of using the insect pathogenic microorganisms for controlling the agricultural insect pests. The first successful large scale microbial control application using conidiospores of the fungus Metarhizium anisopliae was carried out in the Russian Ukraine against the beet weevil, Bothynoderes punctiventris, needed amounts of pure conidiospores were produced in the laboratory for this purpose.

Entomopathogenic viruses, bacteria and fungi are currently used as alternatives to traditional insecticides. Its use should not be generalized because each pest has its own case. In specific cases, viruses proved very effective in managing populations of certain pests as for Lepidoptera and Hymenoptera forest pests in Europe and those introduced in forests in the USA and Canada; also, for controlling the cotton leafworm, potato tuber worm and greater wax moth larvae. They are specific to target insects and highly safe to mammals and the environment. Bacterial diseases like the Milky disease ( Bacillus popilliae ) successfully controlled the Japanese beetle grubs for 10 years after only one soil treatment. Each of the three subspecies of B. thuringiensis attacks larvae of a specific order, i.e., B.t. kurstaki for Lepidoptera, B.t. israelensis for Diptera and B.t. tenebionis for Coleoptera. All commercial products of B.t. are free from exotoxins that pose hazards to man and all organisms in the environment. Some fungi are effective microbial control agents against certain insect pests only under conditions of high R.H. and temperature that are available in glass houses. That is why fungi are also effective at tropical and sub-tropical areas as against cacao insect pests in Brazil. In some instances, fungi ( Beauveria bassiana ) cause allergy to man. They attack non-target insects, adult parsitoids and predators. Thus, fungi have low specificity and pose hazards to biodiversity.

ENTOMOPATHOGENIC BACTERIA: Bacillus thuringiensis (Bt): • Bacillus thuringiensis (or Bt) is a Gram-positive, soil-dwelling bacterium , commonly used as a pesticide. • Bacillus thuringiensis was first discovered in 1901 by Japanese biologist Shigetane Ishiwatari. In 1976, Zakharyan reported the presence of a plasmid in a strain of Bacillus thuringiensis and suggested its involvement in endospore and crystal formation. B. thuringiensis is closely related to B.cereus , a soil bacterium, and B.anthracis , the cause of anthrax: the three organisms differ mainly in their plasmids. Like other members of the genus, all three are aerobes capable of producing endospores . Upon sporulation, B. thuringiensis forms crystals of proteinaceous insecticidal δ-endotoxins (called crystal proteins or Cry proteins ), which are encoded by cry genes. In most strains of B. thuringiensis the cry genes are found within the bacterial plasmid. • Cry toxins have specific activities against species of the orders Lepidoptera (moths and butterflies), Diptera (flies and mosquitoes), Coleoptera (beetles), hymenoptera (wasps, bees, ants and sawflies) and nematodes. Thus, B. thuringiensis serves as an important reservoir of Cry toxins and cry genes for production of biological insecticides and insect-resistant genetically modified crops (GM crops). • The currently known crystal (cry) gene types encode ICPs (Insecticidal crystal

proteins) that are specific to Lepidoptera (cryI), Diptera and Lepidoptera (cryII), Coleoptera (cryIII), Diptera (cryIV), or Coleoptera and Lepidoptera (cryV). 90

Gene Insect activity cry I [several subgroups: A(a), A(b), A(c), B, C, D, E, F, G] lepidoptera larvae cry II [subgroups A, B, C] lepidoptera and diptera cry III [subgroups A, B, C] coleoptera cry IV [subgroups A, B, C, D] Dipteral cry V-IX various

Mode of action: • Unlike typical nerve-poison insecticides, Bt acts by producing proteins (delta- endotoxin, the "toxic crystal") that reacts with the cells of the gut lining of susceptible insects . These Bt proteins paralyze the digestive system, and the infected insect stops feeding within hours. Bt-affected insects generally die from starvation, which can take several days. • B.t. forms asexual reproductive cells, called spores, which enable it to survive in adverse conditions. During the process of spore formation, B.t. also produces unique crystalline bodies . • When eaten, the spores and crystals of B.t. act as poisons in the target insects. B.t. is therefore referred to as a stomach poison . • B.t. crystals dissolve in the intestine of susceptible insect larvae. When insects ingest toxin crystals the alkaline pH of their digestive tract causes the toxin to become activated. It becomes inserted into the insect's gut cell membranes forming a pore resulting in swelling, cell lysis and eventually killing the insect. • They paralyze the cells in the gut , interfering with normal digestion and triggering the insect to stop feeding on host plants. B.t. spores can then invade other insect tissue, multiplying in the insect's blood, until the insect dies. • Death can occur within a few hours to a few weeks of B.t. application, depending on the insect species and the amount of B.t. ingested.

Advantages: • Highly Specific : The specific activity of Bt generally is considered highly beneficial. • Safe to Beneficial Insects : Unlike most insecticides, Bt insecticides do not have a broad spectrum of activity, so they do not kill beneficial insects. This includes the natural enemies of insects (predators and parasites), as well as beneficial pollinators, such as honeybees.

• Can integrate with other IPM methods : Bt integrates well with other natural controls. For example, in Colorado, Bt to control corn borers in field corn has been stimulated 91

by its ability to often avoid later spider mite problems. Mite outbreaks commonly result following destruction of their natural enemies by less selective treatments. • Non -toxic to people: Perhaps the major advantage is that Bt is essentially nontoxic to people, pets and wildlife. This high margin of safety recommends its use on food Crops or in other sensitive sites where pesticide use can cause adverse effects. • Environmental friendly : Because of their specificity, these pesticides are regarded as environmentally friendly, with little or no effect on humans , wildlife , pollinators, and most other beneficial insects. Commercial history & Uses: • Bacillus thuringiensis was first discovered in 1911 as a pathogen of flour moths from the province of Thuringia, Germany. It was first used as a commercial insecticide in France in 1938, and then in the USA in the 1950s. • Bacillus thuringiensis serovar israelensis , is widely used as a larvicide against mosquito larvae , where it is also considered an environmentally friendly method of mosquito control . • The commercial Bt products are powders containing a mixture of dried spores and toxin crystals. They are applied to leaves or other environments where the insect larvae feed. • Different toxins have different spectra of activity. Different strains and serotypes have been developed by different companies. Spores and crystalline insecticidal proteins produced by B. thuringiensis have been used to control insect pests since the 1920s. They are now used as specific insecticides under trade names such as Dipel, Halt, Delfin and Thuricide . • Typical agricultural formulations include wettable powders, spray concentrates, liquid concentrates, dusts, baits, and time release rings. • Use at rates of 100-300 g active ingredient (ai) per hectare ensuring that the crop is well covered with the spray suspension. Apply while larvae are small and repeat every five to seven days if infestations are high. Bt-based sprays can be applied up to the day of harvest. • This microbial insecticide was originally registered in 1961 as a General Use Pesticide (GUP). It is classified as toxicity class III - slightly toxic. Products containing B.t. bear the Signal Word CAUTION because of its potential to irritate eyes and skin. • Bt can be multiplies on LB (Luria-Berstani) Medium or nutrient agar medium or T 3 agar medium. The pure culture of Bt maintained on agar slopes will be inoculated on media aseptically. After inoculation, it takes 48-72 hours for complete sporulation, depending on the strain. The Bt spores and crystals then be recovered from broth and dried to get powder.

Bacillus thuringiencis strain kurstaki (BIOBIT, DIPEL, MVP, THURICIDE, HALT, STEWARD)-Trade Names Vegetable Cabbage diamondback moth, Tomato a nd tobacco hornworm insects Lepidopteran larvae, American Bollworm ( Hellicoverpa armigera ), Pink bollworm ( Pectinophera species), spotted bollworm ( Erias insulana )diamond back moth ( Plutela xylostella (Linnaeus)) and other vegetable pests such as Colorado potato beetle ( Leptinotarsa decemlineota (Say)) and forest insects. Field and forage European corn borer (granular formulations have given good control crops of first generation corn borers). Alfalfa caterpillar, alfalfa webworm

Fruit crop insects Leafroller. Ac hemon sphinx 92

Bacillus thuringiencis strain Israelensis Mosquito. (Vectobac, Mosquito Dunks, Mosquito Bits, Gnatrol, Black fly. Bactimos, etc.)-Trade Names Fungus gnat Bacillus thuringiencis strain San diego /tenebrionis Colorado potato beetle. (Trident, M-One, M-Trak, Foil, Novodor, etc.)-Trade Elm leaf beetle. Names Cottonwood leaf beetle. • Many Bt genes (Cry IA) have been isolated and used to transform crops, also known as Genetically Modified Crop (GMO) or Transgenic Crop (Cotton MECH-162, MECH-184, MECH-12) thereby making them resistant. Now, there many Bt hybrids are available in Indian market and also under evaluation (see.www.dbtbiosafety.nic.in). • The Belgian company Plant Genetic Systems was the first company (in 1985) to develop genetically engineered ( tobacco ) plants with insect tolerance by expressing cry genes from B. thuringiensis . • Since 1996, a wide range of crop plants have been genetically engineered to contain the delta- endotoxin gene from Bacillus thuringiensis . These "Bt crops" are now available commercially in the USA, India and other countries. They include "Bt corn", "Bt potato", "Bt cotton" and "Bt soybean". Such plants have been genetically engineered to express part of the active Cry toxin in their tissues, so they kill insects that feed on the crops. Recently, Bt brinjal issue has surfaced in Indian news and print media. • Bt cotton, a transgenic plant, produces an insect controlling protein Cry1A(c), the gene for which has been derived from the naturally occurring bacterium, Bacillus thuringiensis subsp. kurstaki (B.t.k.). The cotton hybrids containing Bt gene produces its own toxin for bollworm attack thus significantly reducing chemical insecticide use and providing a major benefit to cotton growers and the environment. (visit http://www.envfor.nic.in/ divisions/ csurv/geac/ bgnote.pdf for background note on Bt cotton in India) • US Based MNC, MONSANTO is the pioneer in GM crops research and development.

ENTOMOPATHOGENIC VIRUS: The family Baculoviridae includes the nuclear polyhedrosis viruses (NPV) and granulosis viruses (GV).

NPV (Nuclear Polyhedrosis Virus): • The nuclear polyhedrosis virus (NPV) which belongs to the sub group Baculoviruses is a virus affecting insects, predominantly larval stages of moths and butterflies. • NPVs are largely restricted to insects and most species are relatively host specific . They are known to infect over 500 species of insects, and are best known from the Lepidoptera. • They have also been recovered from Hymenoptera, Diptera, Thysanura, Trichoptera and Crustacea (shrimp). The NPV from Alfalfa looper, Autographica californica (AcMNPV) is the one of the most intensively studied species. • It has been used as a pesticide for crops infested by insects susceptible to contraction. Though commercialization of the viral pesticide is slow as the virus is very species specific, making it effective under certain circumstances. • Heliothis sp. is a cosmopolitan insect pest attacking at least 30 food and fibre yielding crop plants. They have been controlled by the application of NPV's Baculovirus heliothis. In 1975, Environmental Protection Agency,U.S.A. registered the B.heliothis preparations. Structure: • The virus strain itself is protected in a polygonal structured capsid . This enables the virus to infect cells more easily, and aids in reproduction of the virus. When the capsid

is broken down within a host, virus strains are released and begin reproduction. Once there is a significant build up of virus, symptoms become noticeable. 93

• The infectious virus particles or virions of NPVs can be enveloped singly (SNPV type) or multiply (MNPV type) and are occluded in protein bodies called polyhedra . NPV polyhedra may contain few to many virions. Mode of action & symptoms: • Infection with baculoviruses occurs when a susceptible host eats the polyhedra or granules, which are dissolved in the basic digestive gut juices. The virions are released when the protein matrices dissolve. The virions enter the nuclei of midgut cells and eventually infect many of the tissues and organs in the insect, primarily the fat body, epidermis, and blood cells. • The virus enters the nucleus of infected cells, and reproduces until the cell is assimilated by the virus and produces crystals in the fluids of the host. These crystals will transfer the virus from one host to another. • The host will become visibly swollen with fluid containing the virus and will eventually die, turning black with decay. Once there is a significant buildup of virus, symptoms become noticeable. The symptoms in the affected insect are; discolouration (brown/yellow), stress (regurgitation), decomposition (liquification), and lethargy (slow moving to no movement at all, refusal to eat). Insect larvae infected with NPV usually die from 5 to 12 days after infection depending on viral dose, temperature, and the larval instar at the time of infection. • Just before dying, larvae often crawl to the tops of plants or any other available structure where they die and decompose. • Infection with baculovirus was historically called "wilting disease" because the tissues of the host liquefy and infection of the epidermis causes the host to appear to melt, releasing virus particles into the environment.

• Insect larvae infected with NPV usually die from 5 to 12 days after infection depending on viral dose, temperature, and the larval instar at the time of infection. • Millions of polyhedra are contained in the fluid mass of the disintegrating larvae and fall into feeding zones (leaves, leaf litter) where they can be ingested by other conspecific larvae. It is transferred from insect to insect through crystals in all of their bodily emissions. • Symptoms: The symptoms in the affected insect are; discolouration (brown/yellow), stress (regurgitation), decomposition (liquification), and lethargy (slow moving to no movement at all, refusal to eat). • The virus is unable to affect humans in the way it affects insects as our cells are acid- based, when it requires an alkaline-based cell in order to replicate. It is possible for the virus crystals to enter human cells, but not replicate to the point of illness. • Mortality of infested insects is nearly 100%. • Bleach and UV light have been found to prove effective in killing the virus .

• Lymantria dispar , commonly known as gypsy moth, is a serious pest of forest trees. It has been successfully controlled by gypsy moth Baculovirus i.e. NPV preparations. 94

• NPV's have also been commercially produced against mustard saw fly ( Athalia lugens proxima ) and cotton pests ( Helicoverpa armigera, Spodoptera litura ) under the name biotrol-VTN, Ha-NPV and Sl-NPV, respectively. • NPVs must replicate in the nuclei of living host cells. They cannot be produced in culture media without living cells . This means that the production of NPV isolates as microbial insecticides requires a colony of insects or an acceptable insect tissue culture. This is more expensive than producing organisms such as the bacterium Bacillus thuringiensis in an artificial medium. • Used as a microbial insecticide, NPVs can provide relatively fast kill and many are very host specific . • NPV epizootics are very impressive and, although they are important as naturally occurring mortality factors for many insect species, they often occur after the pest insect has exceeded the economic injury level . This is especially true when the crop that is being damaged by this insect has a relatively low economic threshold. • All are specific to arthropods, most to a narrow range of Lepidoptera . Research on the production of NPVs as microbial insecticides has been primarily aimed at developing more efficient methods of production in insect tissue culture, as well as developing more virulent NPV strains. • Most of the research on virulence involves inserting genes that produce toxic substances into the polyhedral gene . For example, genes for insect specific toxins, inserted into the polyhedral gene locus are expressed at the time that the polyhedral gene would have been expressed. The toxins kill the insect at an earlier stage than occurs in a normal infection.

GC (Granulosis Viruses) : • Granulosis viruses (GV) are closely related to NPVs and are similar in structure and pathogenesis. The major difference between these two groups is that the virions are singly occluded into small occlusion bodies called granules . • Like the NPVs, reproduction begins in the nuclei of host cells. Tissues infected and gross pathology are also very similar to NPVs. • GVs have only been recorded from Lepidoptera . • There are three major genetic types of GV. Type 1 GV described from the cabbage looper, Trichoplusia ni , only infects the midgut cells and subsequently the fat body cells. Type 2 GVs, first isolated from the codling moth, Cydia pomonella , parallels NPV infections. Type 3, known only from the western grapeleaf skeletonizer, Harrisina brillians , infects only the midgut tissues. In vivo production costs and

narrow host spectrum limits their attractiveness to industry. 95

MASS PRODUCTION OF NPV: • NPV can multiply only in the living host, as it is obligate in nature . • The PIBs are stable and provide the means by which the virus infectivity is preserved outside the host. It is the PIBs that are applied as microbial biopesticide. • A diseased full grown larva releases on an average 200 crore of PIBs. • A larval equivalent (LE) is the average amount of NPV produced in infected larvae . In most cases, where LEs are quoted, they are not based upon actual counts of NPV but are merely used to make up the product. The amount of NPV produced in larvae is highly dependent upon the quality of inocula, conditions of the larvae and production system. The Indian standard prescribed for NPVs is 1X109 PIBs per ml of the product . • The term Larval Equivalent (LE)-has come into use in connection with the development of Heliothis zea NPV. It was adopted to represent the average yield of polyhedral from one-virus infected last-instar larva of Healithis zea i.e. 6X10 9 polyhedra = 1 larval equivalent. The viral polyhedral counts can be made easily using haemacytometer. Field dose of 500LE per ha is recommended for most insect pests on commercial crops. Mass multiplication of Helicoverpa NPV (Ha NPV): • The lab-reared or field collected larvae are reared on a semi-synthetic diet consisting of Chickpea grain flour, antibiotics, vitamins, live yeast and preservatives such as methyl para hydroxyl benzoate with agar-agar as a solidifying agent. • Multicell cavity trays (Cell wells-which are now commercially available), are filled with chickpea flour based semi-synthetic diet @ 4-5 ml/cell. • In place of artificial diet, chickpea grains soaked overnight in sterile water is also used as a cheaper source of food for the larvae. • The grains are inoculated with the virus and grains are periodically added in the vial as per requirement. • In case of artificial diet, after solidification, the diet surface is inoculated with a standard dose of PIBs with the help of a syringe @ 20 l/cell. • Third to fourth instar larvae are released in to the tray one per cell and lid is fixed. • The dead larvae are collected in a container with distilled water in a ratio of 1 larvae/1 ml. After 5 days, these are macerated in a waring-blender using distilled water @ 2ml per diseased larvae. • For crude preparation, the filtrate is diluted in water to make solution of 250 ml for every 100 larvae, which consists of 100LE (Larval Equivalent). • For purification, the filtrate is centrifuged at 400-500 rpm for 10minutes and the settled debris is discarded and the supernatant is subjected again to centrifugation at 5000-6000 rpm for 30 mts. • The residue (PIBs) settled is collected in fresh distilled water. • Water can be added to make 250ml volume for each 100 larvae macerated. • The stock solution of NPV is standardized for PIB counts with the help of a haemocytometer and a light microscope. • The whole process is completed within 15 days: 8 days for incubation period, 5 days for processing and 2 days for standardization of the product, packing etc. • Robin blue is added at farm level before being sprayed on crop so as to protect the NPV from UV rays, as NPV is sensitive to UV rays.

• Sometimes, Jaggery is also added to spray solution, so as to encourage the insect to eat more food, as the NPV is basically Stomach Poison. 96

• In India, liquid concentrate of the PIBs in distilled water is developed without any additives, while wettable powder formulations of NPV have also been developed. • The term Larval Equivalent (LE) -has come into use in connection with the development of Heliothis zea NPV. It was adopted to represent the average yield of polyhedral from one-virus infected last-instar larva of Healithis zea i.e. 6X10 9 polyhedra = 1 larval equivalent. • The standardization of the final product is based on; polyhedral counts, and bioassay tests on healthy insects.

ENTOMOPATHOGENIC FUNGI: • An entomopathogenic fungus is a fungus that can act as a parasite of insects and kills or seriously disables them. These fungi usually attach to the external body surface of insects in the form of microscopic spores (usually asexual, mitosporic spores also called conidia). • Under permissive conditions of temperature and (usually high) moisture, these spores germinate, grow as hyphae and colonize the insect's cuticle; eventually they bore through it and reach the insects' body cavity (hemocoel). Then, the fungal cells proliferate in the host body cavity , usually as walled hyphae or in the form of wall-less protoplasts (depending on the fungus involved). • After some time, the insect is usually killed (sometimes by fungal toxins) and new propagules (spores) are formed in/on the insect if environmental conditions are again permissive; usually high humidity is required for sporulation. • Many common and/or important entomopathogenic fungi are the asexual phases Beauveria, Metarhizium , Nomuraea, Paecilomyces (Isaria), Hirsutella . • Since they are considered natural mortality agents and environmentally safe , there is worldwide interest in the utilization and manipulation of entomopathogenic fungi for biological control of insects and other arthropod pests. • Some 700 species of entomopathogenic fungi have been reported from over 100 genera, but only about 10 of these have been used or currently being developed for insect management. Outline classification of fungal entomopathogenic genera and examples of insect hosts are given in the following table for information : Genus of entomopathogenic fungi Host insects Commercial products Lagenidium Mosquitoes L. giganteum registered in USA Coelomomyces Mosquitoes Conidiobolus, Entomophaga Aphids, flies, caterpillars Entomophthora, Erynia, Aphids, flies, caterpillars Neozygites, Pandora Cordyceps, Hypocrella,Torrubiella Scale insects, butterflies and moths, beetles Aschersonia, Beauveria, Scale insects, whiteflies, Several products based on B. Hirsutella, Metarhizium aphids, grasshoppers and bassiana, B. brongniartii, M. Nomuraea, Paecilomyces, locusts, butterflies and anisopliae, P. fumosoroseus or Tolypocladium, Verticillium moths, beetles V. lecanii

Important entomopathogenic fungi used in Insect Pest Management are given below:

Fungi Host Insect Beauveria bassiana Lepidoptera, Coleoptera, Hemiptera, few Diptera and White Muscardine Fungi Hymenoptera Metarhizium anisopliae Lepidoptera, Coleoptera, Hemiptera, & Diptera Green Muscardine Fungi (popularly used against locusts & Grasshopper in Africa) Paecilomyces fumosoroseus Lepidoptera, Thysanoptera Yellow Muscardine Fungi Verticillium anisopliae Homoptera (Aphids and Whiteflies) and Mites Verticillium lacanii Nomuraea rileyi Lepidoptera Hirsutella thompsonii Eryiophid mites (Spider mites , Citrus red mite, coconut

mite) Aschersonia alyroides Homoptera 98

Advantages of Entomopathogenic Fungi: Insect pathogenic fungi are important natural regulators of pest insect populations, and their great potential as biological control agents is derived from a number of characteristics: Safe for greenhouse managers and applicators. Safe for consumers (no toxic residues) Safe for soils and water supplies Effective against pests of both field and greenhouse crops Compatible with existing pesticide application systems Easily integrated into many crop management systems Compatible with organic production systems Safer for beneficial insects than chemical insecticides • Doses: Generally in case of Metarhizium anisopliae it is recommended @ 3-5 X 10 12 conidia /ha. • Production : Most entomopathogenic fungi can be grown on artificial media. However, some require extremely complex media; others, like Beauveria bassiana and exploitable species in the genus Metarhizium , can be grown on starch-rich substrates like cereal grains (rice, wheat). • Virulence : The Entomophthorales are often reported as causing high levels of mortality (epizootics) in nature. These fungi are highly virulent. The anamorphic Ascomycota (Metarhizium, Beauveria etc.) are reported as causing epizootics less frequently in nature. • Also important are their properties regarding specificity (host range), storage, formulation, and application.

Grasshoppers killed by the Healthy and Fungus-infected Healthy and Fungus entomopathogenic fungus aphids (Beauveria bassiana ) infected Beauveria bassiana Colorado potato beetles

Healthy and Fungus-infected Fungus ( Nomuraea) infected Fungus ( Beauveria bassiana) whitefly Helicoverpa armigera infected Helicoverpa armigera adult 99

General Mass Production Procedures for Entomopathogenic Fungi • Most of the entomopathogenic fungi can be grown on a variety of solid substrates or in liquid media. • Sorghum grain, rice, rice flakes, puffed rice, wheat; wheat flakes, maize, cowpea grains, millets, rice bran, wheat bran, groundnut hull meal, Bengal gram husk, coffee husk, potato, carrot etc are some of the solid substrates used for mass production of entomopathogenic fungi. • These solid substrates are moistened, sterilized and inoculated with the fungus in bottles/polypropylene bags and incubated at optimum temperature (around25 0C) and humidity (more than 70%) for a period of 10-20 days. • Then the conidia are harvested directly in water containing wetting agent like Teepol and vegetable oil by repeated washing or centrifugation and used as foliar sprays. • Alternatively talc based formulations can be prepared by homogenizing the substrate along with fungal growth into a fine powder and mixing with inert materials like talc (1:1 or 1:2 proportion) and used as foliar sprays. • The spore/conidia conc. in the formulation should be more than 1x10 8 spores / g/ml. • These fungi can be grown in static liquid cultures or shake cultures or in fermentors using cheap and inexpensive liquid media like molasses, carrot extract, potato extract/ synthetic media. Solid state Mass Production of Beauveria bassiana (White Muscardine Fungi) • Solid substrates like cereal grains can be used for mass multiplication of this fungus. • The pure culture of the fungus should be grown on PDA (Potato Dextrose Agar) slants in tubes for 10 days, incubating at 26 oC. • The fungus should be suspended in sterile water mixed with 0.15% tween. • The spore load in suspension to be adjusted to 10 6 per ml by adding sterile distilled water. • 200g of whole grains are crushed in grinder into small pieces, which can pass through 12 mesh sieve. The crushed grains to be then taken into 0.2mm thick 250g capacity polypropylene bags or bottles and moistened with 190ml water. • The bags of bottles should be closed with cotton plugs, and sterilized at 120 oC for 45 min. After cooling, the lumps of the gains in the bottles should be broken with fingers (avoid contamination wearing gloves) and inoculated with 5ml of spore suspension (2X10 2 conidia/ml). • The inoculated bags are incubated at 25 oC for 25 days. Cotton plugging of bags is preferred for proper aeration . • The spore mass along with grain carrier should be taken out from the bags or bottles after 25 days, and air-dried under laminar flow for 3 days are dried at 40 oC for 1 day, and ground to a mixer to fine powder. • The fine powder is suspended in required quantity of water along with 0.02% tween 80 for preparation of spray fluid. • The spore count per ml should be 10 6 to 10 9 conidia. • Talc powder has to be sterilized in an autoclave at 120 oC for 1 hour. • After cooling, grain spore powder missed with a sterilized talc powder carrier and the mixture should be dried under shade or laminar air flow hood for 3-4 days under aseptic conditions. • Then it should be sieved and packed in already sterilized polypropylene bags.

• These formulations can be used in field against crop pests.

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Beauveria bassiana (White Muscardine Fungi) commercial details: • Target pests: Strain Bb 147 is most commonly being used against borers, European Corn borer ( Ostrinlo nubilalis )and Asiatic corn borer (O furnacalis Guenee ); different strain (GHA) is also being used against whitefly, thrips, aphids and mealybugs; and ATCC 74040 is effective against a range of soft-bodied coleopteran, homopteran and heteropteran pests. • Biological activity: The entomopathogen invades the insect body. Fungal conidia become attached to the insect cuticle and, after germination, the hyphae penetrate the cuticle and proliferate in the insect's body. High humidity or free water is essential for conidial germination and infection establishes between 24 and 48 hours. The infected insect may live for three to five days after hyphal penetration and, after death, the conidiophores bearing conidia are produced on cadaver. The fungus is insect specific. • Formulation: Clay microgranular formulation colonised by sporulating mycelia. • Trade Name: DISPEL. • Application: Used as foliar sprays. Application rates depend upon the crop and the pests to be controlled. The normal application rate on commodity crops is 750 to 1000 ml of product per hectare, for ornamentals under cover or outdoors 24 to 80 ml per 10 litres and on turf and lawns 32 to 96 ml per 100 square metres. • Purity: Formulations should contain conidia of Beauveria bassiana at a concentration of 2.3 x 107 spores per ml or at least 5 x 108 spores per gram. Viability of the spores is determined by culture on nutrient agar and counting the colonies formed. Efficacy is checked by bioassay with an appropriate insect. Detailed identification of the specific strain in any formulation requires DNA and isoenzyme matching with the registered strain held in a type culture collection. • Compatibility: The products may be used alone or tank mixed with other products such as sticking agents, insecticidal soaps, emulsifiable oils, insecticides or used with beneficial insects. Do not use with fungicides and wait 48 hours after application before applying fungicides.

Future ahead: Perhaps the greatest potential for future progress in biological control lies in improving the success of microbial pathogens . Many of these organisms are highly desirable as biocontrol agents: they attack a narrow range of insect hosts, they are not hazardous to humans or domestic animals, and they do not pose a threat to the environment. As a group, though, pathogens have never proven to be quite as reliable as other forms of pest control. They are vulnerable to desiccation, ultraviolet radiation, and high temperatures. They may not survive long enough in the environment to encounter a host, and even if they survive, their virulence may be too low to overcome the host's defenses. In the past few years, however, there has been encouraging progress in the development of microbial insecticides. These are commercial suspensions of spores, toxins, or virus particles that can be mixed with water and sprayed onto crops just like conventional insecticides. In many cases, microbial insecticides are better than conventional insecticides because they suppress pest populations without eliminating natural populations of predators and parasites. A great deal of research is still needed before we can begin to benefit from the full potential of biocontrol. Fortunately, new developments in biotechnology enabled us to create new strains of microbial pathogens that are more virulent, easier to mass produce, and less sensitive to temperature and humidity. Work is currently underway to transform a common soil microbe, Pseudomonas fluorescens , into a pathogen of soil-dwelling insects by implanting the delta- endotoxin gene from Bacillus thuringiensis . Clearly, there are major changes in biocontrol that lie just over the horizon. We know the success of Bt-Cotton and other transgenic crops in the recent 10 years.

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Lecture: 16 Microbial control-entomopathogenic nematodes (EPNs) important species-mode of infectivity and examples-mass multiplication. Biological control of weeds with insects-advantages & disadvantages of biological control.

ENTOMOPATHOGENIC NEMATODES (EPNs) • Entomopathogenic nematodes are soil-inhabiting, lethal insect parasitoids that belong to the phylum Nematoda, commonly called roundworms . • Although many other parasitic nematodes cause diseases in plants, livestock, and humans, entomopathogenic nematodes, as their name implies, only infect insects. • Entomopathogenic nematodes (EPNs) live inside the body of their host , and so they are designated endoparasitic . • They infect many different types of soil insects, including the larval forms of butterflies, moths, beetles, and flies, as well as adult crickets and grasshoppers . • EPNs have been found in all inhabited continents and a range of ecologically diverse habitats, from cultivated fields to deserts. • Entomopathogenic nematodes (EPNs) are used to control several agriculturally important insect pests of the different orders. • The first nematode ( Steinernema carpocapsae ) used successfully in the control of an insect pest was reported 30 years ago from Australia. • Commonwealth Scientific and Industrial Research Organization (CSIRO) was the first in the world to use EPNs commercially against black vine weevil in ornamentals and against currant borer moth in black currants. • Eighty three described EPN species have been identified (64 species of Steinernema and 8 species of Heterorhabditis and 1 species of Neosteinernema) from various insects or from the soil worldwide. • The most commonly studied genera are those that are useful in the biological control of insect pests, the Steinernematidae and Heterorhabditidae . In the Steinernematidae and Heterorhabditidae, an area of the anterior part of the intestine of the infective juvenile (IJ) is modified as a bacterial chamber . In this chamber the infective juvenile carries cells of a symbiotic bacterium. The bacterium carried by Steinernematidae is usually a species of the genus Xenorhabdus, and that carried by Heterorhabditidae is a species of Photorhabdus.

Pathogenicity (mode of infectivity): • The soil-living infective juveniles carry the symbiotic bacteria in the intestine. • The infective juvenile (IJs) of EPN is microscopic organism having 0.5 to 1.5 mm long depending on species. The third stage juvenile of these nematodes have closed mouth and anus and cannot feed until it finds an insect. Usually it is found in soil and is activated by insect movement and then follows a gradient of CO 2 to find the insect

larvae. • The infective juvenile (IJ) of EPNs, enter through the insect's natural body openings,

the mouth, anus or respiratory inlets (spiracles) and then penetrate into the blood 102

cavity from the gut. If the mode of entry is by mouth or anus, the nematode penetrates the gut wall to reach the hemocoel, and if by spiracles, it penetrates the tracheal wall. Having reached the haemocoel, the nematodes release the bacteria, which propagate rapidly and kill the host within 3 days . • The bacteria and the digested insect tissue is the nutrient source for the nematodes which proliferate enormously. Two to 3 weeks later, up to 300,000 new nematodes may emerge from one infested white grub. On the other hand, it only takes 2-3 nematodes to kill the insect. • Even though the bacterium is primarily responsible for the mortality of most insect hosts, the nematode also produces a toxin that is lethal to the insect .

Host range: • The entomopathogenic activity of steinernematid and heterorhabditid species has been documented against a broad range of insect pests in a variety of habitats. They have been used inundatively in a number of high value cropping systems. The nematode- bacterium complex kills insects so rapidly that the nematodes do not form the intimate, highly adapted, host-parasite relationship characteristic of other insect nematode associations. The major commercially available EPN species are Heterorhabditis indica and Steinernema carpocapsae • These two species are very effective against Gram pod borer ( Helicoverpa armigera ), Tobacco caterpillar ( Spodoptera litura ), Mustard saw fly ( Athalia lugens proxima ), Diamond back moth ( Plutella xylostella ), Sorghum stem borer ( Chilo partellus ), Sugarcane borer ( Chilo sacchariphagus indicus ), Castor semilooper ( Achaea janata ), Brinjal fruit borer ( Leucinodes orbonalis ), Brinjal spotted beetle ( Epilachna vigintioctopunctata ), Bihar harry caterpillar ( Spillosoma obliguae ), Fig moth ( Cadra cautella ), Termite ( Odontermes obesus ), Greater wax moth ( Galleria mellonella ), Sorghum grain moth ( Corcyra cephalonica ), Cabbage semilooper ( Trichoplusia ni ), Bhendi fruit borer ( Earias vittella ), White grub ( Holotrichia consanguiea), Rhinoceros beetle ( Oryctes rhinoceros ), Cabbage leaf webber ( Crocidolomia binotalis ), Rice leaf folder ( Cnaphalocrosis medinalis ), Rice stem borer ( Scirpophaga incertulas ). • DD-136 is commercially available EPN, complex of Steinerneam carpocapsae (nematode) and Xenorhabdus nematophilus (bacteria) is recommended for use in rice, sugarcane and apple pests.

Life cycle: • The infective juvenile becomes a feeding third-stage juvenile, feeds on the bacteria and their metabolic byproducts, and molts to the fourth stage and then to males and females of the first generation. • After mating, the females lay eggs that hatch as first-stage juveniles that molt successively to second-, third-, and fourth-stage juveniles and then to males and females of the second generation. The adults mate and the eggs produced by these second-generation females hatch as first-stage juveniles that molt to the second stage. The late second stage juveniles cease feeding, incorporate a pellet of bacteria in the bacterial chamber, and molt to the third stage (infective juvenile), retaining the cuticle of the second stage as a sheath, and leave the cadaver in search of new hosts. In some hosts, the second generation is omitted and the eggs that are laid by first-generation adult females develop into infective juveniles. The cycle from entry of infective juveniles into a host from emergence of infective juveniles from a host is temperature-dependent and varies somewhat for different species and strains. However, it takes about 7-10 days at 25C in Galleria mellonella .

Differences for the Heterorhabditidae are that all juveniles of the first generation become hermaphrodites. In the second generation, males, females, and hermaphrodites develop. 103

• The infective juveniles do not feed but can live for weeks on stored reserves as active juveniles, and for months by entering a near-anhydrobiotic state. This is almost certainly the most important survival strategy for the nematode. The length of time that juveniles survive in the soil in the absence of a host depends upon such factors as temperature, humidity, natural enemies, and soil type. Generally, survival is measured in weeks to months, and is better in a sandy soil or sandy- loam soil at low moisture and with temperatures from about 15-25 C than in clay soils and lower or higher temperatures.

Mass multiplication: In vivo production and formulation technologies: It is far too expensive to rear EPNs by in-vitro media as they required separate media source for nematodes growth and their associated bacterium with suitable fermentor. The in-vivo process, however, lacks any economy of scale; the labour, equipment, and material (insect diet) costs increase as a linear function of production capacity. However, the first successful and commercial scale of mass production of EPN species; Heterorhabditis indica, Steinernema carpocapsae on larvae of greater wax moth, Galleria mellonella L. (Lepidoptera: Pyralidae) and formulation of these nematodes have been developed after three years of rigorous research by Multiplex Biotech Pvt. Ltd., Tumkur, Karnataka, India. This is a pioneered organization commercializing these entomopathogenic nematodes reared in vivo method to increase their virulent and survival. Galleria mellonella are most commonly used host insect to mass produce these beneficial nematodes because of its rich nutrient source available in body and Entomopathogenic nematodes are often applied to sites and ecosystems that routinely receive other inputs that may interact with nematodes including chemical pesticides, surfactants (e.g., wetting agents), fertilizers, and soil amendments. Often it is desirable to tank mix one or more inputs to save time and money. Infective juveniles are tolerant of short exposures (2-8 h) to most agrochemicals including herbicides, fungicides, acaricides, and insecticides. Some pesticides act synergistically with EPNs and therefore improve nematode efficacy in inundative applications. Nematodes are alsocompatible with most inorganic fertilizers when they applied inundatively. Application method: Entomopathogenic nematodes should be applied at the first sign that a pest population is initializing to cause damage. Reapplying nematodes depends on the success of the first nematodes released. Their survivorship and success are based on environmental condition, moisture and soil type and percentage of living nematodes actually released during the first application. Nematodes should be reapplied on sevenday intervals if damage continues. In order to ensure maximum effectiveness, it is crucial to apply them at the optimum environmental conditions needed for their better survival. Therefore, it is best to irrigate the target site, both before and after application because they need moist conditions to prevent desiccation and aid with movement to find hosts . Also, the best results are obtained when the relative humidity is high, ambient temperature is neither extremely hot nor cold, soil temperature is between 10-35 oC, soil is moist and direct sunlight is minimal. All of these factors help prevent the nematodes from drying out and increase their survival and virulent.

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BIOLOGICAL CONTROL OF WEEDS: • Many insects feed upon unwanted weeds, just the same manner they do with cultivated plants. As they damage the noxious and menacing weeds, these insects are considered to be beneficial to man and called as weed killers . Successful eradication of certain weeds due to specific insects is achieved. Later certain insects are specifically employed against deleterious weeds and got rid of them. • In South India, Opuntia dilleni (cactus-prickly pear) was introduced wrongly in 1780 in place of Opuntia coccinellifera for cultivating commercial cochnial insect Dactylopius cocci (scale insect introduced from Mexico-for carmine dye production- which is used as food additive in milk shakes, yogurt). Then for the control of this exotic weed, scale insect, Dactylopius tomentosus was introduced from Sri Lanka (in 1926) and Australia, and is a successful example in India which controlled the weed in just two years. • Lantana camara (wild Sage) was brought to India by British in 1807 as an ornamental plant for Culcutta Botanical Garden. Then in 1850 it was introduced in Dehradun Cantonment park. Then this weed pest spread to all parts of India, and it become very difficult to control the pest. Lantana camara , a troublesome weed was kept in check to some extent in some areas by the coccid, Orthezia insignis S., but later started infesting citrus, coffee, tomato etc. • The seed fly ( Ophiomyia lantana ) introduced from Hawaii, USA for the control of Lantana camera did not establish in our country. • Water hyacinth (Eichhornia crassipes ) was controlled by bruchids, Neochetena bruchi and Neochetina eichhorniae . The grubs of this beetle bore into leaves and their petioles, and the adults feed on leaves. • Parthenium (congress weed) entered in India with imported food grains in 1950s, is one of most seven disastrous weeds in the World, caused damage to crop lands, and it was estimated that the control of this weeds could help in increase of crop yields by 25%. In 1983, the Indian Institute of Horticultural Research (IIHR) introduced the leaf-feeding beetle, Zygogramma bicolorata (Coleoptera: Chrysomelidae) from Mexico for the control of Parthenium . The field release permits were obtained from the Plant Protection Advisor, GOI, in 1984. • Exotic tephritid gall fly, Procecidochares utilis from New Zealand was tested for the control of Eupatorium adenophorum weed (looks like aster) in Nilgiris, TN.

Many a times, scientists tried to introduce various biological control agents for the control of noxious weeds, but some are successful as explained above, and some not established in India.

PROTOZOA : • Their use is limited as their mass production is difficult. • Infects insects of Lepidoptera, coleoptera, orthoptera, hemiptera and diptera. • Farinocystis triboli is pathogenic protozoa on red flour beetle Tribolium castaneum • Malpighamoeba locustae on grasshoppers. • Nosema bombycis (Pebrine disease) on silk worms. (Harmful protozoa)

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Advantages of Biological Control: Biological control is a particularly appealing pest control alternative because, unlike most other tactics, it does not always have to be reapplied each time a pest outbreak occurs . Once natural enemies are released into a new environment, there is a good chance they will become established and provide a self-perpetuating form of control . Biological control is also the only control tactic that increases in numbers and spread , rather than decreases, the species diversity within an agroecosystem. This increased diversity often results in greater stability because wild fluctuations in population density are less common in communities with a diverse food web. The most important advantage to the use of biological control is that it typically offers longer term management than the more traditional technology areas. Longer term control is achieved because biocontrol agents act as if a host specific control method. It is continualy present and impacting the target plant . Another advantage is that the cost for control is typically lower (cost effective) to relative to more traditional control procedures. Typically, biocontrol agents are relesed in relatively low numbers for only a short time in the beginning of the program unlike more traditional methods of control which are used continually over many years. After the releases are discontinued, the agent population increases, if successful and begins to damage the target population. Only in rare circumstances are the agents released continually. Selectivity , it does not intestify to create new pest problems. No Resistance problems: The pest is unable ( or very slow) to develop a resistance Free of side effects Safe to handle or use Highly host-specific: High degree of host specificity Searching ability Survive of low host density Pesicides which are harmful to all parts of the food chain, are not needed. No effect on Non-Target organisms: Suitable biological control organisms do not attack other species Usually a large proportion of the post population is destroyed.

Disadvantages: – Biological control is not a "quick fix" for most pest problems . Natural enemies usually take longer to suppress a pest population than other forms of pest control and farmers often regard this as a disadvantage. – Slow to achieve results and the impact is not dramatic and often unpredictable. . – In most cases it will never exterminate the pest , and hence may lead to partial success . – It also may be difficult to "integrate" natural enemies into a crop or commodity when pesticides are still in use . Beneficial insects are often highly sensitive to pesticides and their resurgence (recovery to pre-spray densities) is usually much slower than that of pest populations. – It is difficult and expensive to develop and supply. – It requires expert supervision – Can be complex

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Lecture: 17 Beneficial insects-important species of pollinators-caprification-pollination syndromes-factors that affect pollination-weed killers-successful stories-scavengers their importance.

• Pollination is one of the most important mechanisms in the maintenance and promotion of biodiversity and, in general, life on Earth. Many ecosystems, including many agro-ecosystems, depend on pollinator diversity to maintain overall biological diversity. Pollination also benefits society by increasing food security and improving livelihoods. • Pollinators are extremely diverse, with more than 20,000 pollinating bee species and numerous other insect and vertebrate pollinators. Therefore pollinators are essential for diversity in diet and for the maintenance of natural resources. The pollination is a " free ecological service ".

POLLINATORS • A pollinator is the biotic agent (vector) that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain. Though the terms are sometimes confused, a pollinator is different from a pollenizer, which is a plant that is a source of pollen for the pollination process. Some plants are self-fertile or self-infertlie requires cross pollination. • The good examples of dependency of plants on insects for pollination is Smyrna fig, depend on wasp Blastophaga psenes that transfers pollen from Capri fig. Bees: • The most recognized pollinators are the various species of bees, which are plainly adapted to pollination. • Bees typically are fuzzy and carry an electrostatic charge. Both features help pollen grains adhere to their bodies, but they also have specialized pollen-carrying structures; in most bees, this takes the form of a structure known as the scopa, which is on the hind legs of most bees , and/or the lower abdomen (e.g., of megachilid bees), made up of thick, plumose setae. • Honey bees, bumblebees, and their relatives do not have a scopa, but the hind leg is modified into a structure called the corbicula (also known as the " pollen basket "). • Most bees gather nectar, a concentrated energy source, and pollen, which is high protein food, to nurture their young, and inadvertently transfer some among the flowers as they are working. • Euglossine bees pollinate orchids, but these are male bees collecting floral scents rather than females gathering nectar or pollen. Female orchid bees act as pollinators, but of flowers other than orchids. Eusocial bees such as honey bees need an abundant and steady source of pollen to multiply. Honeybees: • Honey bees travel from flower to flower, collecting nectar (later converted to honey), and pollen grains. The bee collects the pollen by rubbing against the anthers. The pollen collects on the hind legs, in a structure referred to as a "pollen basket". • As the bee flies from flower to flower, some of the pollen grains are transferred onto the stigma of other flowers.

• Nectar provides the energy for bee nutrition; pollen provides the protein. When bees are rearing large quantities of brood (beekeepers say hives are "building"), bees deliberately gather pollen to meet the nutritional needs of the brood. 107

• A honey bee that is deliberately gathering pollen is up to ten times more efficient as a pollinator than one that is primarily gathering nectar and only unintentionally transferring pollen. Good pollination management seeks to have bees in a "building" state during the bloom period of the crop, thus requiring them to gather pollen, and making them more efficient pollinators. • Thus the management techniques of a beekeeper providing pollination services are different from, and to some extent in tension with, those of a beekeeper who is trying to produce honey. The practice of rearing bee colonies for pollination services started in USA in 1910. Other insects: • Lepidoptera (butterflies and moths) also pollinate to a small degree. They are not major pollinators of our food crops, but various moths are important for some wildflowers, or other commercial crops such as tobacco. • Many other insects accomplish pollination. Wasps (esp. Sphecidae and Vespidae), bombyliid flies and syrphid flies are important pollinators of some plants. • Beetles, midges, and even thrips or ants can sometimes pollinate flowers. • Green bottle or carrion flies are important for some flowers, usually ones that exude a fetid odor. • Some male Bactrocera fruit flies are exclusive pollinators of some wild Bulbophyllum orchids that have a specific chemical attractant present in their floral fragrance. • Some Diptera (flies) may be the main pollinators in higher elevations of mountains whereas Bombus species are the only pollinators among Apoidea in alpine regions at timberline and beyond. • Other insect orders are rarely pollinators, and then typically only accidentally (e.g., Hemiptera such as Anthocoridae, Miridae. Pollination of fig: • There are many varieties of figs, but the most delicious one known to most of us is the Smyrna (Izmir) fig , which is named after the city in Turkey. This fig is now cultivated in California. • Ficus ‘Spanish Dessert’ is a cultivar of Ficus smyrna , the best variety of fig to grow. However this type of fig only has female flowers and if you want fruit from it you will also need a Ficus ‘Capri’ Capri fig, whose fruit is generally inedible, but is the only variety to have both male and female flowers, and is essential for the pollination of the Smyrna varieties. The Smyrna fig can be pollinated only by pollen from the Capri fig . • Like all figs, the flowers are enclosed within fruit, inaccessible to all normal pollen vectors like wind, bees and other insects. • Capri fig is the host of a specialized fig wasp, which spends most of its life cycle in capri fig. Although the Capri fig bears a great deal of pollen, this can be released from the Capri fig and reach the fruit of the Smyrna fig only with the help of a tiny wasp- like insect known as the fig wasp. The fig wasp lives in the Capri figs until it is ready to lay its eggs. The female wasp leaves the capri fig through a tiny pore at the base of the fruit. Coated with pollen, the tiny wasp searches for the developing fruit to lay eggs, and when wasp enters into Smyrna fig, the pollination takes place. It crawls into the Smyrna fig and rubs off the pollen on the flowers. Vertebrate pollinators: • Bats are important pollinators of some tropical flowers. Birds, particularly hummingbirds, honeyeaters and sunbirds also accomplish much pollination, especially of deep-throated flowers. Other vertebrates, such as monkeys, lemurs, possums,

rodents and lizards have been recorded pollinating some plants. 108

Pollination Syndrome: • Pollination syndromes are suites of flower traits that have evolved in response to natural selection imposed by different pollen vectors , which can be abiotic (wind and water) or biotic, such as birds, bees, flies, and so forth. These traits include flower shape, size, colour, odour, reward type and amount, nectar composition, timing of flowering, etc. For example, tubular red flowers with copious nectar often attract birds; foul smelling flowers attract carrion flies or beetles, etc. Pollination syndromes are excellent examples of convergent evolution. • The "classical" pollination syndromes as they are currently defined (see below) were developed in the 19th Century by the Italian botanist Federico Delpino. They have been useful in developing our understanding of plant-pollinator interactions.

Pollination Syndromes

Abiotic Pollination Syndromes These plants do not attract animal pollinators

Wind Pollination (Anemophily) Water Pollination (Hydrophily)

Biotic Pollination Syndormes These plants have special triats to attract different type of biotic factors for pollination

Bee Pollination (Melitt ophily) Butterfly Pollination (Psychophily) Moth Polllination (Phalaenophily) Fly Pollination (Myophily) Bird Pollination (Ornithophily) Bat Pollination (Chiropterophily)

Beetle Pollination (Cantharophily) Factors affecting pollination: • Foraging behavior of the bees • Type of the flora • Weather • Field force (number of insects / unit area) • Strength of Bee Colony • Number of colonies • Placement of bee colonies • Pesticides

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WEED KILLERS: • Many insects feed upon unwanted weeds, just the same manner they do with cultivated plants. As they damage the noxious and menacing weeds, these insects are considered to be beneficial to man and called as weed killers. Successful eradication of certain weeds due to specific insects is achieved. Later certain insects are specifically employed against deleterious weeds and got rid of them. • In South India, Opuntia dilleni (cactus-prickly pear) was introduced wrongly in 1780 in place of Opuntia coccinellifera for cultivating commercial cochnial insect Dactylopius cocci (scale insect introduced from Mexico-for carmine dye production - which is used as food additive in milk shakes, yogurt). Then for the control of this exotic weed, Dactylopius tomentosus (scale insect) from Sri Lanka (in 1926) and from Australia was introduced and is a successful instance in India which controlled the weed in just two years. • Lantana camara (wild Sage) was brought to India by British in 1807 as an ornamental plant for Culcutta Botanical Garden. Then in 1850 it was introduced in Dehradun Cantonment Park. Then this weed pest spread to all parts of India, and it become very difficult to control the pest. Lantana camara , a troublesome weed was kept in check to some extent in some areas by the coccid, Orthezia insignis , but later started infesting citrus, coffee, tomato etc. • The seed fly ( Ophiomyia lantana ) introduced from Hawaii, USA for the control of Lantana camera did not establish in our country. • Water hyacinth ( Eichhornia crassipes ) was controlled by bruchids, Neochetena bruchi and Neochetina eichhorniae . The grubs of this beetle bore into leaves and their petioles, and the adults feed on leaves. • Parthenium (congress weed) entered in India with imported food grains in 1950s, is one of most seven disastrous weeds in the World, caused damage to crop lands, and it was estimated that the control of this weeds could help in increase of crop yields by 25%. In 1983, the Indian Institute of Horticultural Research (IIHR) introduced the leaf-feeding beetle, Zygogramma bicolorata (Coleoptera: Chrysomelidae) from Mexico for the control of Parthenium . The field release permits were obtained from the Plant Protection Advisor, GOI, in 1984. • Exotic tephritid gall fly, Procecidochares utilis from New Zealand was tested for the control of Eupatorium adenophorum weed (looks like aster) in Nilgiris, TN. • The Monarch butterfly (Danaus plexippus) is a milkweed butterfly (family: Nymphalidae). The Monarch is a common poisonous butterfly that eats poisonous milkweed in its larval stage and lays its eggs on the milkweed plant. Monarch caterpillars eat the poisonous milkweed leaves to incorporate the milkweed toxins into their bodies in order to poison their predators. The Monarch is a poisonous butterfly. Animals that eat a Monarch get very sick and vomit (but generally do not die). These animals remember that this brightly-colored butterfly made them very sick and will avoid all Monarchs in the future. It is perhaps the best known of all North American butterflies. Since the 19th century, it has been found in New Zealand, and in Australia since 1871 where it is called the Wanderer . A successful weed killer: a) Should not itself be a pest of cultivated plants or later turn into a pest of cultivated crops ( Zygogramma beetle for the control of Parthenium is later found infesting

sunflower). For example, the nymphs and adults of mealy bug. Ferrisia virgata were reported to feed on roots of parthenium weed in Mysore city. The young plants were prone to heavy attack by the bug and the plants died completely due to wilting. Even 110

the vegetable mite ( Tetranychus cucurbitae ) has been observed to infest this weed on the farm of Agricultural College. Dharwad, since, these are polyphagous; they cannot be used as biological control agents. Lantana camara , a troublesome weed was kept in check to some extent in some areas by the coccid, Orthezia insignis S., but later started infesting citrus, coffee, tomato etc. b) Should be effective in damaging and controlling the weed c) Should preferably be a borer or internal feeder of the weed and d) Should be able to multiply in good numbers without being affected by parasitoids and predators. Scavengers: • These are insects which feed upon the dead and decaying plant and animal matter . Since insects help to remove from the earth;s surface the dead and decomposing bodies, which would otherwise be a health hazard, they are referred to as scavengers. In addition to cleaning the filth from human habitations, these insects help to convert those bodies into simpler substances before recycling them back to soil, where they become easily available as food for growing plants. In these respect, termites, maggots of many flies and larvae and adults of beetles are important. • The following are the important groups of insects that serve as scavengers in nature: Coleoptera : Rove beetles; Chafer beetles; Ptilinid beetles; Darkling beetles; Skin beetles; Nitidulids; The carrion beetles; Jewel beetles; Water scavenger beetles; Powder post beetles and bostrychids Diptera : Dady-long legs; Sand flies or moth flies; Midges or gnats; Fungus gnats; Hover flies; Root maggot flies; Muscids Isoptera (white ants) and Hymenoptera (ants) also live and feed upon dead wood, dead animal or decaying vegetable matter.

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Productive insects:

S.No Name Economic product 1 European Honey bee • Honey, The only insect which produces food eaten by man Apis mellifera • Honey bees have to go through a long process to make (Apidae:Hymenoptera) honey. The house bee and the field bee are involved in the process. First the field bee goes out and collects nectar, It is a native of Europe which it stores in an internal honey sac. They bring it back introduced to to the hive and transfer it to the house bee tongue to tongue. Himachal Pradesh and Then the house bee spreads a drop of nectar on the roof of a Punjab during 1962- cell in a comb. During the next couple of days other house 64 and introduced to bees fan their wings over the nectar so that the moisture Kerala and other evaporates (nectar is 80% water and honey is 19% water). states Finally, more house bees cover every cell filled with Indian honey bee modified nectar with a thin layer of wax. Apis cerana indiaca • Honey is used for various purposes. (Apidae:Hymenoptera) • Other products, royal jelly and bees wax also used for various purposes. 2 Lac insect • Lac, a hardened resin secreted by scale insect. Kerria lacca • a scarlet substance that is used for dyeing wool and silk, as (Kerriidae:Homoptera) a cosmetic, and as a medicinal drug. • can be processed to produce shellac, which is used to coat jelly beans, to give fresh fruits and vegetables a glossy finish, and as a wood finish. • Also used for sealing materials • The leading producer of Lac is Jharkhans, followed by Chhattisgarh, West Bengal, Maharastra states of India. • The most common host tress are Kusum and Ber 3 Mulbery Silk worm • Silk cocoons (pupa) are used for production of silk (Sericulture) (Patsilk) • Silk culture has been practiced for at least 5,000 years in Bombyx mori China (Bombycidae: • In the process of producing a cocoon, the caterpillars Lepidoptera) manufacture an insoluble protein (fibroin) in their silk glands, mix it with a smaller amount of soluble gum, and secrete this mixture to yield a single, continuous silk fiber of some 300 to 900 meters (1000 to 3000 feet) long. • The cocoon may be white to yellow in colour • The leading producer is Karnataka • The host plant is Mulbery. Eri Silk worm • This is raised in India only (Ericulture) (Erisilk) • The silk is not reelable like Bombym mori Samia ricini • They are hand-fed with castor or tapioca leaves Muga Silkworm • Indigenous wild silks produced in Assam (Mugasilk) • Fed on som and suvalu leaves Antheraea assamensis • The silk produced is known for its glossy fine texture and durability. • Due to its low porosity the Muga yarn cannot be bleached or dyed and its natural golden color is retained.

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4 Dyes • Deep crimson dye extracted from female cochineal insects. • Cochineal is used to produce scarlet, orange and red tints. Cochineal scale insects • The colouring comes from caramic acid. Dactylopius coccus • Cochineal extract's natural carminic-acid content is usually (Dactylopiidae: 19–22%. Homoptera) • The insects are killed by immersion in hot water (after which they are dried) or by exposure to sunlight, steam, or the heat of an oven. • Each method produces a different colour that results in the varied appearance of commercial cochineal. • The insects must be dried to about 30 percent of their original body weight before they can be stored without decaying. • It takes about 70,000 insects to make one pound of cochineal dye. • Traditionally cochineal was used for colouring fabrics, but today it is used as a fabric and cosmetics dye and as a natural food coloring.

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Lecture: 18 Chemical control- importance and ideal properties of insecticides, classification of insecticides on the basis of origin, mode of entry, mode of action and toxicity-toxicity evaluation of insecticides, acute and chronic toxicities, oral and dermal toxicities, LC 50 (lethal concentration) , LD 50 (leathal dose) , ED 50 (effective dose), LT 50 (lethal time), KD 50 (knockdown dose), KT 50 (knockdown time)- bioassay methods.

• A pesticide is any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any pest. • A pesticide may be a chemical substance, biological agent (such as a virus or bacterium), antimicrobial, disinfectant or device used against any pest. • Pests include insects, plant pathogens, weeds, molluscs, birds, mammals, fish, nematodes (roundworms), and microbes that destroy property, spread disease or are a vector for disease or cause a nuisance. Although there are benefits to the use of pesticides, there are also drawbacks, such as potential toxicity to humans and other animals. • FAO has defined the term of pesticide as: any substance or mixture of substances intended for preventing, destroying or controlling any pest, including vectors of human or animal disease, unwanted species of plants or animals causing harm during or otherwise interfering with the production, processing, storage, transport or marketing of food, agricultural commodities, wood and wood products or animal feedstuffs, or substances which may be administered to animals for the control of insects, arachnids or other pests in or on their bodies.

Classification of Pesticides based on type of pest

Insecticides Substances that prevent, destroy, kill insects Fungicides Substances that prevent destroy or inhibit the growth of fungi in crops. Herbicides Substances used for preventing or inhibiting growth of plants or for killing weeds. Rodenticides Substances that inhibit, destroy or kill rodents Nematicides Substances that prevent, destroy, repel or inhibit the nematodes Chemosterilants Substances that sterilize the insect pests. Molluscicides Substances that prevent, repel, destroy or inhibit the growth of Mollusca. Plant growth Substances that cause the acceleration or retardation of the rate of growth or rate regulators of maturation of plants. Defoliants Substances that cause the plant leave to die and fall away. Desiccants Substances that cause to drain moisture out of the plants causing them to dry. Attractants Substances that attract the insect pests Repellents Substances that repel the insect pest from a treated plant.

Importance of Chemical control: • Conventional insecticides are among the most popular chemical control agents because they are readily available, rapid acting, and highly reliable . • A single application may control several different pest species and usually forms a persistent residue that continues to kill insects for hours or even days after application. • Because of their convenience and effectiveness , insecticides quickly became standard practice for pest control during the 1960's and 1970's. • Pesticides are used both in agriculture and as vector-control agents in public-health

programmes. 114

• In the absence of agro-chemicals, crop production has become an impossible proposition, because it is estimated that India approximately loses 18% of the crop yield valued at Rupees 90,000 crores due to pest attack each year. • The protection of humans from vectors such as mosquitoes is possible only due to pesticides. • Significant amounts are also used in forestry and livestock protection. • Although there are benefits to the use of pesticides, there are also drawbacks, such as potential toxicity to humans and other animals. Overuse, misuse, and abuse of these chemicals have led to widespread criticism of chemical control and, in a few cases, resulted in long-term environmental consequences. • The effectiveness of an insecticide usually depends on when and where the pest encounters it.

Properties of an ideal insecticide: 1. Should be freely available in market in different formulations 2. Should be selective 3. Should be toxic for the target pest 4. Should have quick knock down effect on target pest 5. Should have high tolerance limits 6. Should be safe to humans 7. Should be safe to fish 8. Should be safe to bees and pollinators 9. Should be safe to natural enemies 10. Should be safe to non-target organisms 11. Should have wide range of compatibility with other chemicals 12. Should be cheaper 13. Should be free from offensive smell/odor 14. Should be stable on application 15. Should be non-residual, preferably bio-degradable 16. Should work in multiple mode of action 17. Should not be phytotoxic 18. Should be easy to use 19. Should not allow the insect to develop resistance fast

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Classification on Insecticides

Based on Or igin & Source of Supply Inorganic Insecticides Organic Insecticides Natural Animal Origin Plant Orogin Synthetic Hydrocarbon oils Mode of Entry Contact Insecticides Stomach Poisons Fumigants Systemic Insecticides Mode of Action Phyiscal Poiso ns Protoplasmic Poisons Respiratory Poisons Nerve Poisons Growth regulators

Classification based on origin and source of supply:

1) Inorganic insecticides : • Inorganic insecticides are often derived from mineral origin , elemental sulphur, heavy metals and arsenic and flourine-containing compounds. • Types of inorganic insecticides include elemental sulphur as fungicide and acaricide , boric acid, diatomaceous earth, silica gel, arsenic and fluorine-containing compounds as insecticides, and zinc phosphide as rodenticide . • Considered highly effective against insects. 2) Organic insecticides : • It is possible to make an organic insecticide from a number of different substances/ sources. • It is also possible to buy them commercially. • It should be noted that many organic insecticides are meant to only target a certain species or a few different species.

• Therefore, those who have a variety of insect species they wish to treat will likely need more than one type of organic insecticide.

• Organic insecticides can be classified based on the origin or source. 116

2a) Organic insecticides of animal origin: • Nereistoxin isolated from marine annelid Lumbrineris heteropoda (cartap is the synthetic analogue of neriestoxin, available in the market at Padan, Celedon, popular against rice pests). • Other examples are fish oil resin soap and whale oil against scale insects. • The naturally occurring avermectins (abamectin, emamectin) are macrocyclic lactone derivatives with potent anthelmintic and insecticidal properties, generated as fermentation products by Streptomyces avermitilis , a soil actinomycete. 2b) Organic insecticides of Plant origin or Botanical insecticides: Chemical Source Azadirachtin All parts of Neem Allicin Garlic Pyrethrins Chrysanthemum Jasmolins Flowers of Jasmine Rotenone Stems of roots of several plants Nicotine Tobacco Ryania Stems of Ryania speciosa Matrine, Oxymatrine Roots of Sophora 2c) Organic insecticides of Synthetic origin: • All these are synthesized in chemical labs. • Most of the available insecticides fall in this group. Group Examples Organochlorines DDT, BHC Cyclodienes Endosulfan, aldrin, dieldrin, endrin, Heptachlor Organo Phosphates Acephate, Phorate, Monocrotophos, Phosphamidon, Parathion, Malathion, Nuvan, chlorpyriphos, methyl demeton, ethion, phosalone, quinalphos, fenitrothion, fenthion, phenamiphos, etc. Organo Carbamates Carbaryl, carbofuran, carbosulfan, aldicarb, methomyl etc. Synthetic pyrethroids Allethrin, permethrin, fenvalerate, fluvalinate, deltemethrin, cyhalothrin, bifenthrin, cyfluthrin, alphamethrin, cypermethrin etc. Other groups Neonicotinoids (imidacloprid, thiacloprid, thiamethaxam, acetamiprid, nitenpyram), pyrazoles (fipronil, ethiprole), pyrroles (chlorfenapyr), Spiromesifens etc. Growth regulators Chitin synthesis inhibitors (buprofezin, diflubenzuron, triflubenzuron, lufenuron, novaluron), Juvenile hormone mimics (methoprene, kinoprene, fenoxycarb) 2d) Hydrocarbon oils etc.

Classification based on Mode of Entry: • Insecticides can be classified according to their mode of entry into the insect 1) contact poisons, 2) stomach poison and 3) fumigants. • However, many insecticides belong to more than one category when grouped in this way, limiting its usefulness. Contact poisons:

• These insecticides kill insects when they are hit by or come in contact with the poison. • A chemical that kills insects through skin contact; it does not have to be ingested . 117

• Most insecticides are absorbed directly through an insect's exoskeleton. These compounds are known as contact poisons because they are effective "on contact". • These are capable of gaining entry into insect body either through spiracles or through trachea or through cuticle . The insect does not have to consume it. • Eg: DDT, BHC, methyl parathion, malathion, nicotine, pyrethroids, are contact insecticides. • Now highly refined oil sprays are excellent contact egg poisons. • Most soft-bodied insects like aphids, mites, scales, and white flies are vulnerable to contact insecticides. • They must be sprayed directly on the insects to be effective; any insects that evade the spray survive. These are sprayed or dusted on the insect's body. Stomach poisons: • These are applied on the surface of plants, fabrics, and wood, or are added to baits . • The insecticide is eaten, along with the food material, by insects that chew, such as ants, caterpillars, and grasshoppers, and must be taken into the alimentary canal to be effective. • The chemicals sprayed or dusted on plants, as the insect eats the plant, it is poisoned through stomach. • The best examples are Bacillus thuringiensis (Bt), rotenone, methyl parathion, pyrethroids are stomach poisons. Fumigants: • Fumigants are insecticidal gases , actually contact poisons applied in gaseous form. • They are released in the vapor state (as gases) and enter the insect's body through its tracheal system . • Fumigants are most effective when they are used in an enclosed area such as a greenhouse, a warehouse, or a grain bin. • The gases enter into system through breathing pores and kills the system either hampering nervous system or respiratory system. • Insects that are hard to reach by sprays are killed when they breathe or are exposed to the gas. • Fumigants are used by professional exterminators to kill the cockroaches, bedbugs and to kill insect pests in grain bins/storage. • The soil may be fumigated to destroy grubs that attack roots. • Fumigants are highly toxic , and hence fumigation is a hazardous operation. • Commonly used fumigants are a) Aluminium phosphide (marketed as celphos tablets of 3g each used against storage pests @ 4 tablets/ton. Each tablet produce 1g phosphine gas; ½ tablet is recommended for red palm weevil in coconut). 3 b) Carbon disulphide (CS 2) @ 8-20lbs/1000ft c) EDB (Ethylene Dibromide) @ 1lb/1000ft 3 d) SO 2 fumes by burning sulphur e) DD mixture-a soil fumigant against nematodes f) CCl 4 (Carbon tetra chloride) g) Napthalene h) ED (Ethylene dibormide) i) EDCT (Ethylene dibromide + carbon tetra chloride) Systemic Insecticides

• These are absorbed by plant tissues, so that when insects feed on the sap they are poisoned. 118

• Systemic insecticides are a special type of "stomach poison" and are absorbed by the tissues of a plant without any effects on the plant. • Insect pests ingest the insecticide when they feed on the treated plant. • Systemic insecticides can be incorporated into the soil around ornamentals or bedding plants. The insecticides are absorbed by the roots and transferred to leaves, stems, and flowers . • Examples: Acephate systemic insecticide (Orthene, starthene) is an example of systemic insecticide product used to protect lawns, shrubs, and ornamentals from various insect pests such as white grubs, japanese beetles, and molecrickets. Other examples include Phorate, imidacloprid, carbofuran, monocrotopohs etc., Merit systemic granules give long term control of lawn pests such as white grubs, but the timing of insecticide application is crucial to be effective in killing grubs that feed on grass. • Most of these insecticides applied as granules , but many also applied as foliar sprays .

Classification based on Mode of Action: Insecticides can be classified according to their mode of action: Physical poisons : • These kill insects by exerting a physical effect . • Eg: Heavy oils, tar oils, which causes death by asphyxiation (scales insects) by exclusion of air. • Others like inert dusts effect loss of moisture by their abrasiveness as in aliminium oxide or absorb moisture from the body as does by drie-die, kaolin clay, charcoal. • In the 1930's and 1940's it was common practice for a farmer to hitch a bale of chicken wire behind a team of horses (or a tractor) and drive it through his fields to stir up dust. When the dust settled, it gave the insect pests an abrasive coating that gradually rubbed away their cuticular waxes and caused them to die from dehydration . Although this is certainly not the most reliable method of pest control, it does explain why crops planted near the edge of a well-travelled dirt road often have less insect injury than those on the opposite side of the same field. • A material called drie-die marketed in USA consists of highly porous, finely divided silica gel which when applied to insects in field, abrades insect cuticle, resulting in loss of moisture and finally death of insect. This material is mainly used in stored grains . • Similarly, kaolinic-clay after successive activation with acid and heat can be mixed with stored grain. This clay material absorbs the lipid layer of insect in the exoskeleton, thus allowing to loss moisture, leading to death of insect . • Generally, at household level, to store the rice and other pulses, boric powder is added, to avoid the pest infestation, which causes damage to insect exoskeleton . Protoplasmic poisons: • Cause precipitation of protein, especially destruction of protoplasm of midgut epithelium. • Eg: Arsenical and Flourides are the general protoplasmic poisons. Nerve poisons: • Chemicals which block different enzymes involved in nerve impulse transmission. • Organo carbamates and organo phosphates block/effect acetyl choline esterase (AChE) enzyme which is involved in synaptic transmission, pyrethrin, indoxacarb effect sodium channels in axonic transmission , organochlorines are agonists of GABA gated 119

chloride channels, avermectins are chloride channel activators in axon, neonicotinoids agonize the nicotinic Ach receptors in synaptic transmission. Respiratory poisons : • Block cellular respiration process by reacting with enzymes involved in glycolysis, krebs cycle and ETS. • Eg: HCN, CO inhibit cytochrome oxidase. Rotenone and Phosphine inhibit ETS, General poisons : • Chemicals which mimic hormones, or inhibit the chitin synthesis in insects. • Hormone mimics (JH mimic-methoprene, kinoprene, fenoxycarb), chitin synthesis inhibitors (benzyl ureas-diflubenzuron, novoluron) etc.

Classification based on Toxicity: • Insecticides can be classified according to their mode of action: Insecticide toxicity is generally measured using LD 50 – the exposure level that causes 50% of the population exposed to die.

Classification of Medium lethal dose Medium lethal dose Colour of the Insecticides by the oral route by the dermal route identification Symbols and word in upper acute toxicity dermal toxicity band on the triangle LD 50 mg/kg.. body LD 50 mg/kg. label in lower weight of test Body weight of test triangle animals animals Extremely toxic 1-50 1-200 Bright red POISON in red skull and cross-bones Highly toxic 51 -500 201 -2000 Bright yellow POISON in red Moderately toxic 501-5000 2001-20000 Bright blue DANGER Slightly toxic More than 5000 More than 20000 Bright green CAUTION

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Toxicity evaluation on Insecticides • Toxic interaction of a chemical with a given biological system is dose-related. • The toxic effects are computed by probit analysis given by finney in 1952. • The toxicity of an insecticide to an organism is usually expressed in terms of the LD 50 (lethal dose, also termed as median lethal dose ), that is, the amount of poison per unit weight of the organism required to kill 50% of the test population . The LD 50 is usually expressed in milligrams per kilogram of body weight (mg/kg). Under certain conditions, the term micrograms per insect ( µg/insect) may be used when the chemical is applied topically to the insect. • The LC 50 (median lethal concentration) is the concentration of the chemical in the external medium required to kill 50% of the test population. This value is used when the exact dose given to the insect cannot be determined. For example, the toxicity of an insecticide to mosquito larvae or to fish is usually assessed by the concentration of the insecticide in water that will result in 50% mortality of the organisms which are exposed for a specified period of time. This is expressed as the percent of active ingredient of the chemical in the medium or as parts per million (ppm). • The term LT 50 (median lethal time) represents the time required for 50% mortality of the test organisms at a specified dose or concentration . This method is used when the number of test individuals is limited and is often employed in field tests where it is impossible to collect sut1icient numbers of insects for testing. • In some instances, the rate of knockdown rather than kill is measured as a criterion of toxicity. In such cases, the KD 50 (median knockdown dose) or the KT 50 (median knockdown time) is used. • In other situations, killing or knockdown does not constitute the desired criterion. For example, in testing insect growth regulators or chemosterilants, the object is not to kill the organisms, but rather to affect their developmental stages, fecundity, and egg viability. In such cases, the ED 50 (median effective dose) or EC 50 (median effective concentration) is used to describe the results of such tests. • The choice of 50% lethality is a benchmark to avoid the potential for ambiguity of making measurements in the extremes, and reduce the amount of testing required. Measures such as 'LD 1' and 'LD 99 ' (dosage required to kill 1% or 99% respectively of the test population) are occasionally used for specific purposes.

Increasing the dose beyond the threshold level increases not only the proportion of animals that show response, but the severity of the effect, as well. It is this linear region of the dose-response curve -increased dose, increased response-that is used to measure, describe, and predict the toxicological properties of a pesticide.

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Evaluation of toxicity in higher animals is different from that of insects in that the number of available animals for testing usually is limited. While the process for determining LD 50 is identical, greater emphasis is placed on qualitative rather than quantitative aspects of poisoning. Another characteristic of toxicological tests in higher animals is that, in most cases, the overriding concern is the evaluation of safety for man, while the toxicological studies on insects are conducted basically with an intention to evaluate the efficacy of insecticides against insects. Toxicological testing on higher animals includes evaluation of: (i) Short-term exposure to a pesticide i.e. acute effects (e.g., eye and skin irritation, death) and (ii) Long-term, continual exposure i.e. chronic effects (e.g., impaired liver function, reproductive abnormalities, cancer). Bio-Assay methods: • The measurement of potency of any stimulus (physical, chemical, biological) by means of reactions which if produced in living matter is called bioassay. • There are several ways of administering a chemical to an insect. A commonly employed method is topical application, where the insecticide is dissolved in a relatively nontoxic solvent, such as acetone, and small, measured droplets are applied at a chosen location on the body surface. Other methods like injection method, dipping method, contact method, feeding methods etc. are also used for assessing the toxicity of given insecticide. • Test Insects for Insecticide Toxicology Bioassay methods: Drosophila melanogastor • Test animal for Environmental Toxicology Bioassay Methods: Daphnia , popularly known as water fleas, are small crustaceans that live in fresh water such as ponds, lakes, and streams. They serve as an important source of food for fish and other aquatic organisms. Daphnia are excellent organisms to use in bioassays because they are sensitive to changes in water chemistry and are simple and inexpensive to raise in an aquarium.

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Lecture: 19 Formulations of insecticides-dusts, granules, wettable powders, water dispersable granules, solutions, emulsifiable concentrates, suspension concentrates, concentrated insecticide liquids, fumigants, aerosols, baits and mixtures of active ingredients.

• After an insecticide is manufactured in a relatively pure form (technical grade), it must be formulated before it can be applied. It has to be brought into a form, which may either be readily usable or can be applied in a fairly uniform manner by diluting it (usually with water). • Formulation is the final physical condition in which the insecticide is sold commercially . A pesticide “formulation” is simply the form of a specific product that you purchase and use.

The formulation: makes it possible to use the toxicant readily - readily usable makes it possible to use the toxicant easily - easily usable makes it possible to apply insecticide fairly uniform manner in field makes it possible to apply insecticide under various field conditions makes it possible to apply insecticide even at very low doses makes it possible to dissolve the active ingredient in solvent makes it possible to handle the toxic insecticide accurately makes it possible to handle the toxic insecticide safely-safety to applicator makes it possible to handle the toxic insecticide with equipment easily-easy handling makes it possible to apply the toxic insecticide at target site-safety to environment makes it possible to reduce the load in environment-less pollution improve the properties of toxic insecticide in storage-improves toxicity improve the properties of toxic insecticide in application-easy to apply improve profitability-more profits

The formulation consists of the active ingredient(s) plus various additives, such as solvents, carriers, emulsifiers, or other materials designed to make the product easier and safer to use.

Formulation Active Ingredient (AI)

Additives Carrier Emulsifier Solvents Surfactants Wetting agents

Sticking agents

Spreading agents 123

• Any given active ingredient can often be purchased in more than one formulation. This allows the user to use varying doses as per the pest and crop, and also to choose based on water availability and spray equipment. • Different companies may market the same active ingredient in different formulations. • Different formulations may have different characteristics, including human toxicity and amount (rate) that can be used. Knowing the characteristics of a specific formulation can allow you to use that product most effectively. For example, a soluble powder (SP) formulation is totally soluble in water just as sugar is soluble in coffee ; once dissolved; it stays uniformly within the mixture and does not need agitation in the spray tank. On the other hand, a wettable powder (WP) may look very similar, but the powder does not dissolve in water ; instead, it becomes suspended in the spray mixture, and be continuously mixed to avoid separation. • Often, a number and a letter or letters are indicated after the name of the formulation. This number usually refers to the concentration of active ingredient within the purchased formulation. The number indicates the per cent of active ingredient in the formulation. This is weight/weight. The letters following the number indicates the type of formulation. For example, “30 EC” indicates that this formulation contains 30g of the active ingredient per 100 g of the formulated product. The letters “EC” indicate that the formulation is an Emulsifiable Concentrate. • The price for a given weight of chemical depends largely on the type of formulation, the most expensive being the pressurized aerosol.

Formulations

SOLID formulations LIQUID formulations OTHER formulations

Dusts Emulsifiable Aeroso ls (D) concentrate (EC)

Granules Solution Fumigants (G) Concentrates (SC)

Wettable Powder Baits (WP) or Water Dispersible Powder (WDP)

Water Soluble Others Powder (SP)

Water Dispersible Granules (WDG)

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COMMON FORMULATIONS FOR DRY APPLICATIONS:

Dusts (D/DP): • Dusts are the simplest of all formulations • Easiest to apply • Ready to use formulations • Require less labour • No water required • An insecticide dust is a dry formulation of a contact insecticide . • Dusts consists of active ingredient + inert carrier/diluent + anti caking agent • To prepare a dust formulation the toxicant is diluted either by mixing with or by impregnation on a suitable finely powdered carrier . The carrier may be an organic flour (e.g. walnut-shell flour, wood bark etc.) or pulverized mineral (e.g. sulfur, diatomite, tripolite, lime gypsum, talc, pyrophyllite) or clay (e.g. attapulgite, bentonites, kaolins, volcanic ash). • The toxicant in a dust formulation ranges from 0.65 to 25 per cent. • The dust formulations have a particle size less than 100 microns . Decrease in the particle size normally increases the toxicity of the dust formulation . However, the lower sized particles have a tendency to hang in air for a longer period of time and are susceptible to drift by air currents. • The properties of the diluents employed dictate the quality of the finally prepared dust formulation, and the rate of decomposition of the toxicant. Some toxicants get inactivated in alkaline conditions. • Selection of diluents is also influenced by its compatibility, fineness, bulk density, flow ability, abrasiveness, absorbability, specific gravity and cost. • A good dust formulation must have free flowability and must not ball or cake in the hopper of the duster. • Commercially, in India, dust formulations of lindane 0.65% DP, lindane 1.3% DP, methyl parathion 2% DP, carbaryl 5% DP, carbaryl 10% DP and fenvalerate 0.4% DP are available. • Usually, the dust formulation is recommended @ 25 kg per hectare, and is to be applied in calm weather and in the mornings when the leaves are wet with morning dew. • The problems with the dust formulations are that they are neither very effective and nor economical. • Examples: Carbaryl 5% DP, Carbaryl 10% DP, Phosalone 4% DP, Malathion 5% DP, Quinalhpos 1.5% DP, Cypermethrin 0.25% DP, Endosulfan 3% DP, Endosulfan 4% DP, Fenitrothion 5% DP, Fenvalerate 0.4% DP, Lindane 0.65% DP, Lindane 1.3% DP, Methyl parathion 2% DP, Phenthoate 2% DP, Pyrethrins 0.2% DP, Sulphur 85% DP.

Granules (G): • In the granular formulation the particle is composed of a base made of either inert material or vegetable carrier (like maize cob) with the active ingredient fused with it. • Granulated formulations consist of small pellets (20-80 mesh) containing 2-10 % of the active ingredient. • Granules consists of active ingredient + inert carrier/diluent + solvent

• The granules are prepared either by (a) spray impregnation technique in which the active ingredient is sprayed onto a clay and the solvent allowed to evaporate or (b) 125

agglomeration technique , in which the powdered filler, together with any other additives, are moistened with water or other suitable liquid and formed into granules and dried; or (c) in which the toxicant is applied as a thick slurry over an insert material such as sand. • An insecticide granule is a dry formulation of a generally systemic insecticide, but in some cases some contact insecticide also formulated as granules . • The granules are used mainly in agriculture for soil applications as systemic insecticides (or nematicides) to be absorbed by the roots of a plant and transported to other parts. In the presence of moisture in the soil, the toxicant is released from the granule. The active ingredient is then absorbed through the roots of the plant and acts by systemic action. In paddy fields, the toxicant dissolved in standing water, rises in the leaf sheaths by capillary action and acts as a contact insecticide. Similarly, when the granules are applied in plant whorls (like in sorghum or maize), the toxicant dissolves in the water in the whorls and drips down the stem forming a thin film and acts on the young caterpillars entering the stem through its contact action. • Examples : carbaryl 4% G, carbofuran 3% CG, carfosulfan 6% G, cartap hydrochlorine 4% G, Chlorpyriphos 10% G, endosulfan 4% G, fenthion 2% G, Fipronil 0.3% G, lindane 6% G, phorate 10% CG The advantages of granules are: 1) There is little drift 2) Undesirable contamination is minimized 3) The granules are applied to the soil, hence are not washed off by rains 4) Release of the toxic material is achieved over a longer period of time 5) Water and spray equipment are not required for application 6) Not harmful to the aerial natural enemies 7) Ready to use 8) Less hazardous to applicators The disadvantages of granules are: 1) Not as effective as sprays against many large leaf-eating insects (like caterpillars etc.) 2) Efficacy reduced if moisture is not present in soil 3) More expensive than other sprayable formulations (like WP or EC)

COMMON FORMULATIONS FOR SPRAY APPLICATIONS:

Wettable Powders (WP) or Water Dispersable Powders (WDP): • A substance that does not dissolve in water but remains suspended in it . Usually refers to pesticides that are applied as sprays. • Wettable powders are concentrated powder formulations containing a wetting agent to facilitate mixing the powder with water before spraying . • Wettable Powders contains active ingredient + inert diluent/carrier + wetting agent/ sufactant + anti-caking agent • As wettable powders are not mixed with water until immediately before use , storing and transporting the products may be simplified as the weight and volume of the water is avoided. • Wettable powders may be supplied in bulk or in measured sachets made from water soluble film to simplify premixing and reduce operator exposure to the product.

• The technical material is added to an inert diluent, such as talc or fine clay, in addition to a wetting agent or surfactant and an auxiliary material (such as sodium salts of sulfo 126

acids obtained by sulfonation of petroleum products, sodium salts of lignin sulfo acids) and mixed thoroughly in a ball mill. • Without the wetting agent, the powder will float when added to water and the two phases will not mix. • Sometimes stickers are added to improve retention on plants and other surfaces. • The active ingredient in a wettable powder formulation ranges from 15 to 95 per cent and since 5-85% of it is composed of talc or clay, they tend to settle rather quickly to the bottom of the spray tank unless the mixture is agitated constantly. • In general suspensions are usually more effective than dusts. • Examples: Bacillus thuringiensis in WP, Beauveria bassiana in 1.15% WP, cyfluthrin 10% WP, deltamethrin 2.5% WP, DDT 50% WP, DDT 75% WP, diflubenzuron 25% WP, fenitrothion 40% WP, lambda cyhalothrin 10% WP, lindane 6.5% DP, malathion 25% WP, pirimiphos-methyl 25% WP, sulphur 80% WP, thiodicarb 75% WP) The requirements of water dispersible powder formulation are: • Stability in storage and absence of caking • Quick formation of suspension and slow settling out of solid particles. • Good wettability and spreading treated surface • Retention on treated surface for a longer period Advantages of wettable powders are: • They do not cause damage to materials or places that are sensitive to organic solvents. • They do not dissolve washers and rubber hoses in spray machines or spray tanks. • They leave effective residues in cracks and crevices where sprays cannot penetrate. • They are not phytotoxic when sprayed on foliage even at high concentrations, in contrast to oil-containing sprays, which can cause foliage burning at temperatures above 32°C. Disadvantages of wettable powders are: • They leave spots in areas sensitive to water spots , especially when they contain dyes. • They cause corrosion of valves, nozzles and pumps in sprayers. • They require constant agitation .

Water Soluble Powders (SP): • Water-soluble powders contain a finely ground water soluble solid which dissolves readily upon the addition of water . • A water soluble powder contains active ingredient + inert carrier/diluent + wetting agent/surfactant + anti-caking agent (spreading/sticking agents added before spray) • The formulation usually contains a high concentration of active ingredient . • Carbaryl 85% SP, cartap hydrochloride 50% SP, methomyl 40% SP and acephate 75% SP are registered in India. • Unlike wettable powders, they do not require constant agitation and do not form precipitate.

Emulsifiable Concentrates (EC) . • Most of the synthetic organic insecticides are water insoluble, but soluble in organic solvents such as amyl acetate, carbon tetrachloride, ethylene dichloride, kerosene, xylene, petroleum naphtha, pine oil etc.

• More than 75% of all insecticide formulations are applied as sprays. The majority of these are water emulsions prepared from emulsifiable concentrates, which are solutions of the technical-grade material in an appropriate organic solvent with, 127

enough emulsifier added to allow the concentrate to mix readily with water for spraying. • EC contains active ingredient + solvent + emulsifier + wetting agent/surfactant (spreading/sticking agent added before spray) • When an emulsifiable concentrate is added to water, the emulsifier causes the oil to disperse uniformly throughout the water phase, giving an opaque or milky appearance when agitated. • This oil-in-water suspension is a normal emulsion. • Some of the emulsifying agents in ECs are alkaline soaps, organic amines, sulfates of long chain alcohols, sulfonated aliphatic esters and amides, and materials such as alginates, carbohydrates, gums, lipids, proteins and saponins. • A few formulations are invert emulsions, that is, water-in-oil suspensions . These are opaque and thick, concentrated emulsions resembling salad dressing or thick cream , and are employed almost exclusively as herbicide formulations , because they result in little drift. Emulsifiable concentrates, if properly formulated, should remain stable without further agitation for several days after dilution with water. • Emulsions sometimes are not stable and tend to separate into component parts and this is referred to as “ breaking ”. A small amount of detergent or emulsifier can be added (about four tablespoons per liter of concentrate) and mixed thoroughly to improve its quality. The amount of emulsifier and agitation applied to the emulsion control this phenomenon to some extent. • Also an emulsion may break into two phases due to differences in specific gravity of the components and this partial separation of the emulsion is known as “ creaming ”. This can be returned to the homogenous condition by slight agitation. • Examples : alphamethrin 10% EC, azadirachtin 0.03%, 0.1%, 0.15%, %, 10%, 25% EC, bifenthrin 10% EC, carbosulfan 25% EC, chlorpyriphos 20% EC, cypermethrin 10% EC, 25% EC, decamethrin 2.8% EC, dichlorvos 76% EC, dicofol 18.5% EC, dimethoate 30% EC, endosulfan 35% EC, ethion 50% EC, fenitrothion 82.5% EC, fenpropathrin 10%, 30% EC, fenthion 82.5% EC, fenvalerate 20% EC, fluvalinate 25% EC, lambda-cyhalothrin 2.5% EC, 5% EC, lindane 20% EC, lufenuron 5.4% EC, malathion 50% EC, novaluron 10% EC, oxydemeton-methyl 25% EC, permethrin 25% EC, phenthoate 50% EC, phosalone 35% EC, pirimiphos-methyl 50% EC, profenophos 50% EC, propoxur 20% EC, pyrethrin 2.5% EC, quinalphos 25% EC, benthiocarb 50% EC, triazophos 20% EC, 40% EC.

Solution Concentrates (SC) or Water Soluble Concentrates (WSC) or Water-Miscible Liquids or Soluble Liquids (SL) or Water Soluble Liquid (WSL): • The technical-grade material is miscible with water or alcohol . • The formulation consists of active ingredient + water immiscible solvent + surfactant . • These resemble emulsifiable concentrates in viscosity and color, but they do not form milky suspensions when diluted with water . • Very few insecticides are formulated in this manner. • Examples : alphamethrin 10% SC, beta-cyfluthrin 2.45% SC, chlorfenapyr 10% SC, fipronil 5% SC, imidacloprid 30.5 %SC, indoxacarb 14.5% SC, spinosad 2.5% SC, 45% SC, sulphur 40% SC, thiacloprid 21.7% SC, oberon 2% SC,diflubenzuron 20% SC, monocrotophos 36% SL, phosphamidon 40% SL, imidacloprid 17.8% SL).

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Suspension Concentrate or Flowable (F): • Some insecticides are soluble in neither oil nor water . In this case the technical material is wet-milled with a solid carrier diluent (like inert clay) and water with a suspending agent, a thickener and an anti-freeze compound thus forming a thick creamy pudding-like mixture which mixes well with water but needs frequent agitation. • Flowables may show sedimentation of the solid materials in storage and agitation by shaking makes the sediment redispersed. • Examples : Sevin XLR plus containing carbaryl as an active ingredient is a flowable formulation, chlorfenapyr 10% SC(FI), imidacloprid 48% FS, Oberon 240 SC(F), flubendiamide 480 SC.

Water Dispersable Granules (WDG) : • Water dispersible granules are intended for application after disintegration and dispersion in water by conventional spraying equipment. • WDGs are formulated in many different ways depending on the physico-chemical properties of the active ingredient and the manufacturing equipment available. • This can lead to products of differing appearances and differing particle size ranges. • WDG contains active ingredient + inert carrier/diluent • Examples : Synapse (flubendiamide) 24 WG, Larvin (thiodicarb) 800 WG, Actara (thiamethoxam) 25 WG, Lorsban (chlorpyriphos) 750WG, Tremodor (fipronil) 80WG.

Oil Solutions: • Oil solutions are formulated by dissolving the insecticide in an organic solvent for direct use in insect control. • They are rarely used on crops because they can cause severe burning of foliage. • They are used effectively on livestock, as weed sprays along roadsides, in standing pools for mosquito-larvae control, and in fogging machines for adult mosquito control. • The concentrated solutions may be diluted with kerosene or diesel oil before application.

COMMON FORMULATIONS FOR DIRECT APPLICATIONS:

Aerosols: • Aerosols are the most common of all formulations for home use . • The toxicant is suspended as minute particles (0.1 to 50 microns) in air as a fog or mist. • To produce an aerosol, the active ingredients must be soluble in volatile petroleum oil under pressure . The pressure is provided by a propellant gas. • When the solvent is atomized, it evaporates readily, leaving behind small droplets of the insecticide suspended in air. • In the past, fluorocarbon was used as a propellant gas, but because of its effect on the ozone layer, it has been replaced by carbon dioxide and other gases. • Aerosols are used for the knockdown and control of flying insects and cockroaches, but they provide no residual effect.

• Propoxur 0.1% (Baygon), permethrin 0.2% and resmethrin 0.1%, allethrin 0.1% (Mortein, HIT) are formulated as aerosols.

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Fumigants: • Chemical fumigants are gases or volatile liquids of low molecular weight which readily penetrate the material to be protected. • In most cases they are formulated as liquids under pressure and are stored in cans or tanks. When released in open air, the liquid changes back into gas. • Fumigants are used for the control of insects in stored products but are also important for soil sterilization as a means of killing soil insects, nematodes, weed seeds, and fungi. • However, trained personnel should only handle the fumigants as the gas may prove to be toxic.

Ultra-Low Volume Concentrates (ULV) or Concentrated Insecticide Liquids: • These usually contain a technical product dissolved in a minimum amount of solvent. • They are applied without further dilution by aerial or ground equipment in volumes of 0.6 L to a maximum of 4.7 L /ha in very small spray droplets of 1-15 /u. • The advantage of ULV sprays is that the small droplets can better penetrate thick vegetation and other barriers. • These formulations are sold only for commercial use where insect control is desired over large areas and a high volume of water would constitute a technical difficulty. • Examples: malathion, dimethoate, phosphamidon.

Fogging Concentrates: • These are used in the control of adult flies and mosquitoes and sold for public health use to pest control operators. Fogging machines generate droplets of 1-10 /u. There are two types of fogging machines: (l) Thermal fogging machines, which utilize flash heating of the oil solvent to produce vapor or fog; and (2) Ambient fogger-type machines, which atomize a small jet of liquid into a venturi tube, through which passes an ultra-high velocity air stream. Thermal foggers utilize oil only, usually deodorized kerosene. Ambient foggers use emulsions, water-base or oil-base formulations.

OTHER FORMULATIONS:

Poison Baits: • Formulated baits contain low levels of toxicants incorporated into materials such as foodstuffs, sugar, molasses, etc. that are attractive to the target pest . • These can be purchased commercially or they can be formulated by individuals or by pest control operators. • The poison baits consist of a base or carrier material attractive to the pest species + a plant-based or chemical toxicant in relatively small quantities. • The poison baits are used for the control of fruit flies, chewing insects , wireworms and white grubs in the soil, household pests (especially rodents ) slugs etc. • This method is ideal where other formulations are either not effective or their application is difficult. • The common base used in dry baits is wheat bran with mollases (as an attractant). Such baits are made in the field for the control of locusts, cutworms, armyworms etc. (rice bran+jaggey+monocrotophos/carbaryl @ 10+1+1 (5kG+500G+500mL/500G), 130

made into small balls and broadcasted in field for Spodoptera ; in case of methomyl it is mixed @ 5mL for 5kG of above bait formulation. • Poison baits with liquid bases are used for the control of fruit flies, fruit sucking moths etc. For the control of fruit flies methyl eugenol is used as an attractant, while for fruit sucking moths, mollases or fermenting sugar is used. (100mL malathion+100g sugar/jiggery+ 10L water, mixer kept in small bowls in field for fruit flies; or 5mL malathion+ 5mL sugar solution+ 1L toddy pulisina tati kallu , mixer kept in small bowls in field for fruit flies; methyl eugenol is also used in baits.

Slow-Release Insecticides: These formulations are relatively new and only a few are available commercially. An example is the Shell-No-Pest Strip, which incorporates dichlorvos (DDVP) into strips of polychlorovinyl resin. The insecticide volatilizes slowly, killing flying and crawling insects over a long period of time. Other forms of slow-release insecticides, such as microencapsulated diazinon, methyl parathion, fenitrothion, pyrethrins plus synergists and permethrin, have recently been introduced. Other types of formulations include a lacquer preparation of chlorpyritos, which can be applied with a paint brush; adhesive tapes containing propoxur, diazinon or chlorpyrifos; and briquettes containing the insect growth regulator methoprene for mosquito larva control. Presently these products are not being marketed in India. The method of slow release involves the incorporation of the insecticide in a permeable covering, microcapsules or small spheres with diameters ranging from 15-50 /u . The insecticide escapes through the small sphere wall at a slow rate over an extended period of time, thus preserving its effectiveness much longer.

Abbreviations used in insecticide formulations

a.i. Active ingredient A Aerosol AS Aqueous solution B Bait D Dust DF Dry, flowable EC Emulsifiable concentrate ES Emulsifiable solution F Flowable, liquid FME Flowable micro-encapsulated G Granule L Liquid, flowable LC Liquid concentrate LS Liquid solution LV Low volume OC Oil concentrate OD Oil dispersible OS Oil solution P Pillets ppm Parts per million S Sprayable solution SC Spray concentrate SP Soluble powder TM Trade mark ULV Ultra low volu me WDG Water dispersible granule WDL Water dispersible liquid WP Wettable powder WSL Water soluble liquid WSP Water soluble powder SL Soluble liquid

Pesticide Labelling: As per the regulations of Insecticide Rules, 1971 (as per section 36 of Insecticides Act 1968) the central government, after consultation with Central Insecticides Board and Registration Committee (www.cibrc.nic.in), hereby makes the following rules (chapter V) for packing and lebelling. The following particulars shall be either printed or written in indelible ink on the label of the innermost container of any insecticide and on the outer most covering in which the container is packed: • Name of the manufacturer (if the manufacturer is not the person in whose name the insecticide is registered under the Act, the relationship between the person in whose name the insecticide has been registered and the person who manufactures, packs or distributes or sells shall be stated. • Name of insecticide (brand name or trade mark under which the insecticide is sold.

• Registration number of the insecticide. • Kind and name of active and other ingredients and percentage of each. (Common name accepted by the International Standards Organization or the Indian Standards Institutions of each of the 131

ingredients shall be given and if no common name exists, the correct chemical name which conforms most closely with the generally accepted rules of chemical nomenclature shall be given). • Net content of volume. (The net contents shall be exclusive of wrapper or other material. The correct statement of the net content to terms of weight, measure, number of units of activity, as the case may be, shall be given. The weight and volume shall be expressed in the metric system). • Batch number. • Expiry date, i.e. up to the date the insecticide shall retain its efficiency and safety. • Antidote statement • The label shall be so affixed to the containers that it cannot be ordinarily removed • The label shall contain in a prominent place and occupying not less than one-sixteenth of the total area of the face of the label, a square, set at an angle of 450 (diamond shape).

In addition to the precautions to be undertaken, the label to be affixed in the package containing insecticides which are highly inflammable shall indicate that it is inflammable or that the insecticides should be kept away from the heat or open flame. The label and leaflets to be affixed or attached to the package containing insecticides shall be printed in Hindi, English and in one or two regional languages in use in the areas where the said packages are likely to be stocked, sold or distributed. Labeling of insecticides must not bear any unwarranted claims for the safety of the producer or its ingredients. This includes statements such as, "SAFE", "NON-POISONOUS", "NON- INJURIOUS" or "HARMLESS" with or without such qualified phrase as "when used as directed.

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Lecture: 20 Inorganic insecticides-arsenic Compounds, fluorine and sulphur compounds; plant derived insecticides- neem based products-different commercial formulations containing azadirachtin, neem seed kernel extract, neem cake extract and their uses-nicotine-rotenon-plumbagin and pyrethrum-source, properties & uses.

INORGANIC INSECTICIDES • Inorganic insecticides include compounds of mineral origin and elemental sulfur . • In the following are given some groups of inorganic compounds which were in use as insecticides, rodenticides and molluscicides:

Arsenic Compounds: • In an arsenic compound, the total arsenic content present and the proportion of water soluble arsenic are of importance. If a compound has a very high water soluble arsenic (which is readily soluble in insect’s digestive juices), it is considered ideal for use as an insecticide. • Also higher water solubility of the arsenic results in its higher penetration into plant tissues causing phytotoxicity. Arsenites are phytotoxic, and hence they are mainly used in poison baits. • The arsenates are generally more stable and safer for application on plants than the arsenites . Therefore, arsenites were mainly used in poison baits . However, arsenates are comparatively less toxic to insects than arsenites. • They are stomach poisons with contact action. • Arsenate poisoning in insects causes regurgitation, sluggishness and quiescence. Disintegration of the epithelial cells of the mid gut and clumping of the chromatin of the nuclei are the effects noticed in poisoned insects . • Slow decrease in oxygen consumption is also evident and the death of the insect is primarily due to the inhibition of respiratory enzymes. • Arsenates are not in use in any part of the world. However, the arsenates used in the past include: (i) Lead arsenate: It was first used as an insecticide in 1892 by Moulton for the control of gypsy moth in Massachusetts, U.S.A. The acid orthoarsenate (Pb HAsO4) and the base orthoarsenate (Pb 4(PbOH)(AsO 4)3) were the forms used in the insecticides and the former predominated in the commercial formulations. It is a stomach poison with little contact action. (ii) Calcium arsenate: It was first used in about 1906 as an insecticide. A commercial product consisted of tricalcium arsenate (Ca 3(AsO 4)2) and acid calcium arsenate (Ca 3HAsO 4) and the former predominated. In a freshly manufactured product water soluble arsenic is found in only a small percentage. When stored, water soluble arsenic gets liberated due to decomposition by carbon monoxide and ammonia in the atmosphere. It is a white flocculent powder and was formulated as a dust containing a pink coloring matter and 25-30% metallic arsenic equivalent. Being a stomach poison it was mainly used for the control of leaf eating insects . (iii) Sodium arsenic: Arsenic compound. It is a white to grayish powder. It was used for baiting ants and locusts and for stock treatment for the control of ticks and as a weedicide as well.

(iv) White arsenic (As 2O3): Arsenite compound. This is also known as Arsenious trioxide. It contains 75% arsenic and was used in poison baits for rats, grasshopper, armyworm, ants and cockroaches. 133

(v) Paris green: (CH 3COO) 2Cu.3Cu(AsO 2)2. Arsenite compound. It is a double salt of copper acetate and copper arsenite, and was first used in 1867 for the control of Colorado Potato beetle.

Flourine Compounds: • Fluorine compounds were in use since 1890. • They were principally used as stomach poisons with a limited contact action . • The kill is rather more rapid than with arsenicals . • Their insecticidal properties are related to the fluorine content and solubility in the digestive juices of the insect. • Phytotoxicity of the compound is attributed to its higher water solubility. • Symptoms of poisoning include spasms (excessive muscular contraction and sudden convulsive movements), regurgitation, flaccid paralysis and death. • In insects, metal-containing enzymes such as enolase require magnesium and in poisoned insects, fluoride forms a complex (magnesium fluorophosphates) and thus inhibits phosphate transfer in oxidative metabolism. • Fluorine compounds include sodium fluoride, sodium fluoaluminate and sodium fluosilicate. (i) Sodium fluoride (NaF): It is a white powder, but the commercial product (93-99% purity) was coloured. It was used in baits for the control of cockroaches, earwigs, cutworms and grasshoppers and chewing lice on animals and poultry. (ii) Sodium fluoaluminate (Al 3AlF): Also known as sodium aluminium fluoride or sodium aluminofluoride. It was first used as an insecticide by Marcovitch and Stanley in 1929. In naturally occurring mineral i.e., cryolite, it is found up to 98%. It was used for the control of chewing insects . (iii) Sodium fluosilicate (Na 2SiF 6): It is phytotoxic and hence its use was restricted for fabric moth-proofing.

Other Inorganic compounds: • Other inorganic compounds include sulphur, lime sulphur, sodium tetraborate, and zinc phosphide. Of these only sulphur and zinc phosphide are used for the control of mites and rodents, respectively. Sulphur: • It is primarily used as an acaricide and a fungicide . • It is usually formulated as a dust (90%D), with up to 10% inert material to prevent balling. • Dust flow can be increased by the addition of 3% tricalcium phosphate. • It is also formulated as a wettable powder (80%WP). Lime sulphur: • It is the aqueous solution of calcium polysulfides. • Grison first used it as a fungicide in 1852 and later Dusey in 1886 for the control of San Jose scale. • It is prepared by sulphur solution in calcium hydroxide suspension, preferably under pressure in anaerobic conditions. Calcium tetra- and pentasulfides (found in the mixture) have insecticidal properties. • Beside powdery mildew, scales, mites and aphids on fruit trees can be controlled with this preparation.

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Sodium tetraborate (Na2B4 O7) or Borax: • It is useful for fly maggot control in manure pits and wounds of animals infested by maggots. • Boric acid acts as a stomach poison for cockroaches. Zinc phosphide (Zn3P2): • Zinc phosphide has long been in use for the control of rodents. • It is a dark grey powder and smells like garlic. • It decomposes slowly in the presence of moisture. • It is used as a 2% bait for the control of field rats . • Ingested zinc phosphide reacts with the hydrochloric acid present in the stomach and releases the phosphine gas.

PLANT DERIVED INSECTICIDES BOTANICAL INSECTICIDES

Perhaps much before the man started cultivating food crops; he knew the properties of plants naturally growing in his area at least with regard to their being edible, poisonous, curative against wounds or effective against the common ailments. The experience was passed down the generations. Once he started cultivating the plants and faced the problems of pests, either desperately or due to curiosity he started using plant products available to him to control the pests. In the older literature, there are several hundred plants reported to kill insects, especially ectoparasites like lice etc. In the modern literature several plant species are reported to be effective against agricultural pests. In fact the list keeps on increasing with time. In this chapter only nicotinoids, pyrethrins, neem and rotenoids have been included for the reasons that these compounds are not only commercialized but research on these plants has led to the development of newer molecules and each of these compounds has a unique mode of action. Other insecticides of plant origin include Sabadilla, which is obtained from the ground seeds of Schoenocaulon officinale A. Gray (Liliaceae) of South and Central America, and Ryania, whish is obtained from roots and stem of Ryania speciosa Vahl (Flacourtiaceae) of South America. Sabadilla is used to control thrips and hemipterous insects, and ryania is effective against lepidopterous larvae .

NICOTINOIDS • The principle alkaloid nicotine in tobacco was discovered in 1828, but tobacco itself in insect control was used in 1763. Nicotine is an alkaloid found in the tobacco plants that constitutes approximately 0.6–3.0% of dry weight of tobacco . • Biosynthesis of nicotine takes place in the roots and accumulation occurring in the leaves . • Among the 12 alkaloids present in toabacco, nicotine is most important contributing to 97% of total alkaloids. Nicotine is obtained from the plants Nicotiana tabacum and Nicotiana rustica to the extent of 2-8% (highest quantity). • It functions as an antiherbivore chemical with particular specificity to insects; therefore nicotine was widely used as an insecticide in the past, and currently nicotine analogs such as imidacloprid continue to be widely used. Nicotine represents a class of compounds, "nicotinoids", with a unique mode of action, and hence new compounds such as imidacloprid are called as neo-nicotinoids. • Its biological activity is due mainly to its interactions with acetyl-choline (ACh)

receptors . 135

• At present the use of nicotine sprays is banned in India though it is restricted for use in U.S.A. to home gardens and possibly some greenhouse cultures. There are several reasons for this: (1) Nicotine has a fairly high mammalian toxicity ; (2) Nicotine has a narrow insecticidal spectrum ; it is effective only against soft-bodied insects with piercing mouthparts (e.g. aphids, thrips) and certain species of mites; (3) Nicotine has a very short life span and low residual activity under field conditions. (4) Moreover, nicotine is metabolized and excreted fairly fast in insects . • However, nicotine has an advantage over these insecticides. It acts on a different target in the nervous system of insects , thus insect strains, which develop resistance to anticholinesterase insecticides (like organophosphorus and carbamates), are not likely to develop cross-resistance to nicotine. Also, research on nicotine led to the development of a new generation of synthetic insecticides, "neonicotinoids". • Nicotine mimics a part of the action of acetylcholine by interacting with the nicotinic acetylcholine receptor, that is, the receptor fails to distinguish between nicotine and acetylcholine. Hence, the effects produced by nicotine across the synapses and neuromuscular functions are called "nicotinic effects" in mammals. • Nicotine is contact insecticide , and also cats as fumigant. • Ready to use preparation of nicotine is nicotine sulfate 40%. • Nicotine sulfate is more stable and less volatile. • Mainly used as contact insecticide with marked fumigant action in the control of sucking insects viz., aphids, thrips, psyllids, leafminors and jassids (hoppers).

Tobacco decoction: Prepared by boiling 1 kg of tobacco waste in 10 lts of water for 30 min or steep it in cold water for a day. Then make up to 30 lts. Add 90 gms of soap (addition of soap improves wetting, spreading, and killing properties). Used for control of sucking insects . Nicotine does not leave any harmful residues.

PYRETHROIDS • Pyrethrum is one of the oldest organic insecticides known to man. Even today it is competitive with many of the new generation insecticides for domestic use. • "Pyrethrum" refers to the dried and powdered flower heads of Chrysanthemum cinerariaefolium. "Pyrethrins" are all the toxic constituents of the pyrethrum flowers and "pyrethroids" refer to the insecticides based on the pyrethrins as prototypes. • The principle active ingredient pyrethrum found in flowerlets from 0.7-3.0%. • Pyrethrum has been used on many agricultural crops for control of aphids, beetles, mealybugs, leafhoppers, thrips, cabbage worms, loopers, and many others. • This is principally due to its (1) low toxicity to mammals , (2) non-persistency , and (3) high toxicity to insects coupled with its (4) remarkable effectiveness in causing insect knockdown . • Pyrethrins give rapid knockdown action , which is a characteristic feature , in many cases, reversible, but could lead to paralysis depending on the dose. • The actual chemical ingredients having insecticidal properties are six biologically

active keto-alcoholic esters derived from two acids ( chrysanthemic acid, pyrethric 136

acid ), and three alcohols (pyrethrolone, cinerolone, jasmolone). The chemical structure of natural pyrethrum has shown great potential for synthesis in laboratory, and hence synthetic pyrethroids could be prepared with improved photostability, and wider insecticidal activity. • Pyrethrum powder is prepared by grinding the dried flowers. • The powder is mixed with diluent such as talc, clay, and is known as pyrethrum dust. • It is usually prepared just before use, otherwise it gets deteriorated rapidly. • Pyrethrum is unstable in light, air moisture and alkali. • Pyrethrums are powerful contact insecticides. • Compounds such as piperonyl butoxide (PBO) are added as synergists who increase the toxicity of the compounds.

NEEM: • Native to India and Burma, the neem tree is a member of the Meliaceae, and is known as margosa tree or Indian lilac, Azadirachta indica A. Juss. • A closely related species, the chinaberry tree or Persian lilac (Melia azidarach L.), contains the similar active components as found in A. indica. • Its insect control efficacy was first recognized by the withstanding of neem trees from the locust, which swarmed on the tree, but left without feeding. • The extracts from seeds and leaves have pest insect control activities . • Extraction is easy. The leaves or seeds are merely crushed and steeped in water, alcohol, or other solvents. The extract contains 4 major and perhaps 20 minor active compounds and can be used without further refinement, or the most effective ingredients can be isolated and formulated as commercial products. • The main neem chemical is a mixture of three or four related compounds. They belong to tetranortriterpenoid (limonoids). Azadirachtin: the main agent for controlling insects, representing 90% of the effect on most pests; contents are usually 2-4 mg/g kernel. It is a feeding deterrent and growth regulator, repelling and disrupting the growth and reproduction of pests; Meliantriol: a feeding inhibitor, causing insects to cease eating in extremely low concentrations; Salamlin: a powerful feeding inhibitor. Nimbin and nimbidin : show antiviral activity; others: minor but also active in one way or another. Deacetylazadirachtin is as active as azadirachtin. • The affected insect can no longer feed, breed, or metamorphose, and can cause no further damage to crops . (Multiple mode of action of neem compounds-antifeedancy, repellency, growth regulating compounds). Neem preparations show the following effects: 1. Partial reduction or complete inhibition of fecundity and/or sometimes egg hatchability; 2. Reduction of the life span of adults; 3. Oviposition repellence against females; 4. Direct ovicidal effects; 5. Antifeedant effects against larvae, nymphs, or adults; 6. Formation of permanent larvae; 7. Growth regulating effects at molting between larval (or nymphal) instar and especially in the prepupal stage and giving rise to larval-pupal, nymphal, pupal, nymphal-adult, and pupal-adult intermediates, and to crippled adults.

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Neem based formulations: • All neem based formulations are based on the naturally occurring limonoid azadirachtin , a secondary metabolite present in seeds of neem plants. • Azadirachtin was initially found to be active as a feeding inhibitor towards the desert locust (Schistocerca gregaria ), it is now known to affect over 200 species of insects, by acting mainly as an antifeedant and growth disruptor, and as such it possesses considerable toxicity toward insects. • It fulfills many of the criteria needed for a natural insecticide if it is to replace synthetic compounds. • Azadirachtin is biodegradable (it degrades within 100 hours when exposed to light and water) • Shows very low toxicity to mammals (LD50 in rats is >3,540 mg/kg making it practically non-toxic). Commercial formulations available based on the azadirachtin content: Depending on the various combinations & permutations, the following are the possible Azadirachtin levels prepared by Indian Companies. 1. Azadirachtin 300 ppm (0.03%), 2. Azadirachtin 1500 ppm (0.15%) 3. Azadirachtin 3000 ppm (0.30%), 4. Azadirachtin 5000 ppm (0.50%) 5. Azadirachtin 10000 ppm (1.00%), 6. Azadirachtin 20000 ppm (2.00%) 7. Azadirachtin 50000 ppm (5.00%), 8. Azadirachtin 65000 ppm (6.50%) Neem seed kernel extract (NSKE): • Neem seeds are extracted both by aqueous and solvent methods through aqueous extraction methods, steam distillation, organic solvent extraction methods. NSKE have high contents of azadirachtin. • The NSKE have anti-bacterial, anti-inflammatory, insecticidal, anti-viral, germicidal, anti-fungal properties. • Grind 20 kg of NSK is sufficient water and make in to paste. Add 10 lts of water and soak for 12 hrs, filter through cloth and make up with water to 250 lts to use for an acre. Weekly spray application of 2.5-5.0% NSKE (aqueous) protects cabbage from diamond backed moth, Plutella xylostella. NSKE is used widely for the control of many insect pests, specially leaf eating insects. This is also effective against soft bodied sucking insect pests and also leaf minors. Neem seed kernel powder : @1-2 parts/100 parts of wheat seeds afford protection against stored grain pests for a month. Neem cake: Neem cake is a by-product obtained through cold processing of neem fruits and leaves. It is potential organic manure . It has an adequate quantity of NPK and other micro nutrients as well which promote plant growth. Neem cake protects plant roots from nematodes, root grubs, ants due to its content of residual limonoids . Neem cake also reduces alkalinity of the soil. 1kg of neem cake soaked in 5 lts of water for a week with frequent agitation filtered through a cloth and made up to 10 lts, can be sprayed against citrus leaf minors, acts as antifeedant. Neem oil: @0.5-1.0%. Advantages of Neem formulations: 1. Broad spectrum of activity 2. No Known insecticide resistance mechanisms

3. Compatible with many commercial insecticides and fungicides 4. New mode of action with possible multiple sites of attack. 5. Classified as a biological insecticide for registration purposes. 138

6. Low use rates 7. Compatible with other biological agents for IPM Programme. 8. Not persistent in the Environment 9. Minimal impact of Non-target organisms. 10. Formulation flexibility 11. Application flexibility - can be sprayed or drenched. 12. Non-phytotoxic

ROTENONE: • Rotenone is extracted from the roots of Derris spp (4-9%) and Lonchocarpus spp. (8- 11%). • Derris root is known as fish poison , later used against cater pillars in 1848. • The alkaloid was first isolated by Geoffrey in 1895. • It is oxidized to non-insecticidal compounds in presence of light. • Insects poisoned with rotenone show a steady decline in oxygen consumption followed by paralysis and death.

PLUMBAGIN: • Plumbagin is naturaaly occurring naphthoquinone isolated from roots of Plumbago zeylanica. • This compound is known for its anti-viral properties. • Plumbagin is yellow dye, with anti-microbial, anti-malarial, anti-inflammatory, anti- carcinogenic, anti-fertility, immunosuppressive actions.

Other Botanical Insecticide Sources: Chemical Source Azadirachtin All parts of Neem Azadirachta indica Allicin Garlic Allium sativum Pyrethrins Flowers of Chrysanthemum Chrysanthemum cinerariaefolium Jasmolins Flowers of Jasmine Rotenone Roots of Derris elliptica (leguminaceae) Nicotine Leaves of Tobacco Nicotiana tabacum Ryania Stems of Ryania speciosa Matrine, Oxymatrine Roots of Sophora Ryanodine Roots and stems of Ryania speciosa -- Powdered rhizomes of Acorus calamus -- Seed cake of Pongamia gabra Tephrosin Seed and leaves of Tephrosia spp

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Lecture: 21 Synthetic organic insecticides-chlorinates hydrocarbons-DDT, HCH-cyclodiens-aldrin, dieldrin, chlordane, heptachlor and endosulfan-toxicity & mode of action.

CHLORINATED HYDROCARBONS (CHCs) / ORGANO CHLORINES (OCs):

• An organochloride, organochlorine, chlorocarbon, chlorinated hydrocarbon, or chlorinated solvent is an organic compound containing at least one covalently bonded chlorine atom. • Organochlorine insecticides include a group of chlorinated hydrocarbons comprising of DDT and its analogues, γ-HCH including its isomers and the cyclodienes. • They contain carbon, hydrogen and chlorine, some have oxygen and sulfur. • Their wide structural variety and divergent chemical properties lead to a broad range of applications. • They are insoluble in water • They are soluble in organic solvents (kerosene, xylene, benzene etc.) • They are unstable in alkalis. • They are highly persistant chemicals . • They have long residual action . • They are cheap per unit area cost. • They available in different formulations.

DDT: D ichloro Diphenyl Trichloroethane

• DDT is one of the most well-known synthetic pesticides. • It is a chamical with a long, unique, and controversial history. • First synthesized in 1874 by German Chemist Othmar Zeidler , DDT's insecticidal properties were discovered in 1939 by Swiss Chemist Paul Muller .It was used with great success in the second half of World War II to control malaria and typhus among civilians and troops. The Swiss chemist Paul Muller was awarded the Nobel Prize in Medicine in 1948 "for his discovery of the high efficiency of DDT as a contact poison against several arthropods. After the war, DDT was used as an agricultural insecticide, and soon its production and use skyrocketed. • In 1962, American biologist Rachel Carson wrote Silent Spring . The book cataloged the environmental impacts of indiscriminate DDT use in the US and questioned the logic of releasing large amounts of chemicals into the environment without fully understanding their effects on the environment or human health. The book suggested that DDT and other pesticides cause cancer and that their agricultural use was a threat to wildlife, particularly birds. Its publication was a signature event in the birth of the environmental movement; it produced a large public outcry that led to a 1972 ban in

the US. DDT was subsequently banned for agricultural use worldwide under the Stockholm Convention, but limited, controversial use in disease vector control continues. Along with the Endangered Species Act , the US DDT ban is cited by 140

scientists as a major factor in the comeback of the bald eagle, the national bird of USA, from near-extinction in the contiguous US. In India also DDT use for Agriculture was banned , but the DDT is allowed only for use in mosquito control programnmne by Ministry of Health and Family Welfare for public health purpose. • The toxicity of DDT is due to pp-DDT isomer, which constitutes about 70-80% in commercial product. Pure p,p'-DDT is a white, tasteless, almost odourless crystalline solid with needle-shaped crystals. • It is practically insoluble in water but soluble in many organic solvents such as acetone, benzene, carbon tetrachloride, kerosene, diesel oil, etc. Highly fat soluble . • Stability to photooxidation makes it a highly persistent insecticide. It could persist on the foliage for over a month due to its low vapour pressure (no fumigant action) and lipophilicity (fat soluble). • It has little action on phytophagous mites. • Commercial formulations of DDT were non-phytotoxic, except on cucurbits. Phytotoxic to cucurbits. Not to be used in root crops • Banned for use in Agriculture in India. Restricted its use in India only for public health purpose-mosquito control. Banned for use in World. • Following DDT application, secondary infestation of aphids, mites and coccids observed . • It is a nerve poison with contact and stomach action with high persistency. DDT affects the sensory organs and nervous system of both vertebrates and invertebrates. In insects it opens sodium ion channels in neurons, causing them to fire spontaneously. DDT-poisoned insect exhibit tremors throughout the body and the appendages, characteristically labeled "DDT jitters ”. The sequence of symptoms of poisoning is as follows: 1. Hyperextension of the legs and uncoordinated movements, 2. Tremors throughout the body, 3. Ataxia (loss of coordinated motion) 4. Hyperactivity resulting from external stimuli, 5. Repeated falling on the back and righting efforts, 6. Disappearance of fast tremors, 7. Prostration with the heart still beating, 8. Finally, paralysis and death. • It acts slowly. Toxicity of DDT increases with decrease in temperature, hence it is said to have“negative temperature dependence (coefficient)”. • In mammals it produces hyper-excitability and tremor, and later convulsions. • It accumulates in fats and milk of human and animals. Its residues were recorded in human milk, bird eggs, dead animal tissues, water and all samples. • Potential mechanisms of action on humans are genotoxicity and endocrine disruption. • DDT is supected to cause cancer. DDT is classified as moderately toxic pesticide. • DDT is available in 5%D, 10%D, 50%WP, 25%EC formulations. • DDT analogues: The discovery of the insecticidal properties of DDT stimulated the search for analogueous organochlorine compounds. Although hundreds of compounds were synthesized, only a few (DDD, methoxychlor, dicofol, and DMC) were found to be sufficiently active and of low cost to be suitable for commercial exploitation.

DDD or TDE 2,2-bis-(p-chloro This chemical has lower mammalian toxicity as phenyl)-1,1-dichloroethane compared to DDT. Not in Use. Methoxychlor This is a biodegradable insecticide, a substitute for DDT Dicofol This has little or no insecticidal activity but is used to

control mites on a wide variety of crops DMC or Chlorfenithol This is effective against both eggs and active stages of several mite species. 141

• DDT metabolism: There are five principal routes of metabolism in various organisms: (i) Oxidation to DDA (ii) Oxidation to dicofol (in insects and mites ) (iii) Oxidation to dichlorobezophenone (iv) Dehydrochlorination to DDE: In insects the most important route of DDT metabolism is through its conversion to DDE , (v) Reductive dechlorination to DDD

HCH (HEXACHLORO CYCLO HEXANE):

• Hexachlorocyclohexane (HCH) was first prepared by Michael Faraday in 1825. • Theoretically there can be many isomers of HCH, of which seven (α, β, γ, δ, ε, η, and θ) are known. The α and β-isomers were discovered by Meunier in the late 1880s. In 1912, Van der Linden confirmed the presence of these two isomers and reported the presence of two additional isomers, the γ and δ. The insecticidal properties of HCH were discovered in England and France in 1942. The toxic principle in HCH is the γ- isomer , named Lindane after its discoverer. • HCH is prepared by the chlorination of benzene in ultraviolet light. • Use of HCH on some edible crops imparts an "off-flavour " or " taint ," this is particularly true of potatoes. Pure γ-isomer or lindane does not impart this taint . • Lindane is phytotoxic to cucurbits . • In general, the isomers of HCH are relatively stable to light, high temperature, hot water, and acid, but they are dechlorinated by alkali. • The technical product of HCH consists of five isomers named a, β, γ, δ, ε in the

following proportion: 55-70, 5-14, 10-18 , 6-10, 3-4%, respectively. The γ isomer (lindane) is the only highly insecticidal chemical of its type. • Lindane is soluble in water to the extent of 10 ppm but soluble in organic solvents. 142

• Symptoms of typical lindane poisoning in insects include tremors, ataxia, convulsions. and prostration. • Compared to DDT, lindane is quicker in action , the symptoms of poisoning occurring much more rapidly after the administration of a toxic dose. • HCH is a nerve poison, with contact and stomach action . • It has some fumigant action also. • In adequate dosage or repeated applications may lead to resistance in bed bugs. • Following application of HCH, seconday infestsation of jassids occur . • Should not be mixed at the time of sowing, since it affects germination (not recommended for seed treatment.) • Used against soil insects, Used against leaf rollers (due to its fumigant action). • Used against mosquitoes in public health. • It is excreted out rapidly without accumulation in fat bodies unlike DDT. • HCH formulations, 5%D, 10%D and 50%WP. • Lindane formulations, 20%EC, 0.65%D, 10%G. • Recently use of Lindane has been extended to control storage garing pests by treating gunny bags, bins, stacks and godowns etc. • Lindane does not interact with any specific enzyme, although it is a better inhibitor of Na+, K+, and Mg +2 -ATPase than DDT

CYCLODIENES • Cyclodiene compounds are a group of highly active insecticides. • However, many of them have long persistency and their use is restricted . • They include chlordane, heptachlor, aldrin, dieldrin, isodrin, endrin, endosulfan, mirex, chlordecone, and the chlorinated terpene, camphechlor (toxaphene). • This is a group of highly chlorinated insecticides prepared by the diene-synthesis or Diels-Alder reaction . • Most cyclodienes like chlordane, heptachlor, aldrin and dieldrin were very persistent, highly lipophilic and posed a hazard of entering the food chain. Endrin was extremely toxic to fish . For these reasons these insecticides have been banned in several countries including India. As on now, the only cyclodiene which is being used for the control of agricultural pests is endosulfan .

Endosulfan:

• The compound is both an insecticide and acaricide . • Nerve poison with both contact and stomach action . It has slight fumigant action also. • It is a brownish crystalline solid consisting of two isomers, α and β. Technical endosulfan is a mixture of these forms in the ratio of 4: l. • It is insoluble in water but moderately soluble in organic solvents.

• It is absorbed through the skin and very toxic to fish . • Unlike most other cyclodiene insecticides it is low in persistency and still used. 143

• It undergoes oxidation in insects, mammals, and plants to form a primary insecticidal metabolite, endosulfan sulfate. Endosulfan and the sulfate are hydrolyzed to form endosulfan diol. • Endosulfan is effective for the control of beetles, cutworms, and aphids. • Safe to bees • Does not encourage secondary infestation of mites. • It is highly toxic to fish. • Endosulfan formulations: Thiodan 35%EC or 4%D, 4-6%G • Endosulfan is banned for use in Kerala and Karnataka.

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Lecture: 22 Organo phosphates-systemic, non-systemic and translaminar action with examples-brief mode action-toxicity, formulations & uses of malathion, methyl parathion, diazinon, dichlorvos, fenitrothion, quinalphos, phosalone, chlorpyriphos, phosphomidon, monocrotophos, methyl demeton, dimethoate, triazophos, profenphos, acephate and phorate.

ORGANOPHOPHOROUS INSECTICIDES:

• The organophosphorus (OP) compounds, first developed by Gerhard Schrader in Germany during late 1930s, are one of the largest groups of insecticides in use today. • Three of these compounds, i.e., TEPP, parathion and Schradan, despite their high mammalian toxicity, were used as insecticides on a worldwide scale . • Tetraethyl pyrophosphate (TEPP) was the first OP insecticide , which was developed in Germany during World War II as a by-product of nerve gas development. • Bladan (containing TEPP-tetra ethyl pyro phosphate) was the first OP insecticide used, followed by parathion and schradan (first systemic insecticide) used in insect pest manamgement. • Methyl parathion has replaced parathion (i.e. ethyl parathion) in many areas of the world for the control of agricultural insect pests. • Organophosphorus insecticides are related in chemical structure and in mode of action to the toxic "nerve gases " of World War II , sarin, tabun, and soman. • The OP compounds have two distinct features: firstly, they are acute toxicants of high level of activity , and, secondly, they are chemically unstable, or nonpersistent, and are quite biodegradable by most organisms and in the environment . These qualities make them useful as substitutes for the persistent organochlorines for the control of insect pests in agriculture and public health. • Virtually thousands of OP compounds have been synthesized in the past 50 years, but not all have reached commercialization. About 100 OP insecticides (on active ingredient basis) are in commercial use throughout the world today. In addition to insecticides and acaricides, this group has defoliants, fungicides, herbicides and nematicides as well. • Organophosphorus compounds are neutral ester or amide derivatives of phosphorous acids carrying a phosphoryl (P-O) or thiophosphoryl (P-S) group. • Most organophosphates conform to the general structure: (RO) 2P(A)X, where R is methyl or ethyl, A is sulfur or oxygen, and X can vary a great deal and is the acidic group that is especially subject to chemical attack because of the positive charge developing on the phosphorus atom.

Gen eral OP structure Malathion Monocrotofos

• OPs are the largest group of insecticides

• OPs are also the most diverse in their toxic effects . • They are contact, stomach, and systemic poisons . 145

• Some are of short residual life as DDVP, TEPP. • Some have long residual life as diazinon, fenthion. • Some are broad spectrum as parathion, phosalone, quinalphos. • Some are soil insecticides such as phorate. • Some are nematicides such as thionazin, dichlorofenthion. • Some are acaricides such as monosrotophos, quinalphos. • Some are true plant systemics, such as dimethoate, phosphamidon • Some are animal systemics such as fenchlorphos • Some are pseudo-systemics as parathion • Some are fumigants such as DDVP, trichlorphon. Advantages of OPs: • Rapid action • Wide spectrum of activity • Low persistence (break down to non-toxic metabolites) • Low dosage per uint area • Do not accumulate in animal body Disadvantages of OPs: • High mammalian toxicity • High acute toxicity • Mostly red labeled (Extremely toxic) Mode of action of OPs: • Complex physiological processes are involved in the transmission of nerve impulses. • At myoneural junctions (in mammals and in insects), the terminal portion of the muscle and the nerve fibre are slightly negative with respect to the outside. On receipt of a stimulus, this gradient is altered so that the inside becomes less negative, and an action potential moves down the nerve; when this potential reaches the nerve ending at the myoneural junction, acetylcholine is released, which diffuses through the synaptic gap (about 100Å wide) between the nerve and the muscle and is adsorbed onto the muscle ending. This interaction of acetylcholine with the receptor end of the muscle gives rise to an action potential in the muscle that responds by contracting. After its purpose is accomplished, the acetylcholine has to be hydrolyzed by acetylcholinesterase so that the muscle returns to its original state, ready to respond to future stimuli. • The organophosphorus compounds act by phosphorylating cholinesterase, an enzyme that plays a vital role in hydrolyzing acetylcholine. The OPs form complexes that are either irreversible or prevent readily release of the enzymes . • The reaction between acetylcholine (ACh) and cholinesterase (H.E) takes place in three stages and can be represented by the following sequence:

At this stage there is equilibrium between the enzyme and its substrate on the one hand and a complex of the two on the other.

The complex yields choline and acetylated enzyme in the second stage. The final stage is the deacetylation reaction in which the acetylated enzyme is hydrolyzed to give the free enzyme and

acetic acid. 146

In the living organism these reactions proceed at a fast rate so that there is no accumulation of acetylcholine across the synapse or at the neuromuscular junction. The choline portion that is removed and the acetic acid combines again (with the help of other enzymes) to form new acetylcholine and the cycle is repeated.

• The organophosphorus compounds act by phosphorylating cholinesterase, an enzyme that plays a vital role in hydrolyzing acetylcholine. The OPs form complexes that are either irreversible or prevent readily release of the enzymes . • Inhibition of an esterase enzyme by organophosphorus compounds. (1) Formation of Michadis complex; (2) phosphorylation of the enzyme; (3) reactivation reaction; (4) Aging” Symptoms of poisoning: In Vertebrates: The toxicity of OP insecticides is due to the inhibition of cholinesterase. Hence the symptoms of acute poisoning are those of stimulation of acetylcholine receptors in the parasympathetic nervous system. The symptoms include sweating, salivation, urination, defecation, lachrymation, nausea, vomiting, abdominal cramps, miosis (constriction of the pupil), bradycardia (slowing of the heart), and hypotension (drop in blood pressure). These symptoms are called muscarinic effects , as similar effects are produced by muscarine, a housefly fungus, Amanita museana . Also, since the accumulation of acetylcholine at the junctions of motor nerves and skeletal muscle and in ganglia of the autonomic nervous system takes place, additional symptoms like the involuntary twitching of the muscles, muscle spasms, weakness of respiratory muscles leading to dyspnea and cyanosis are also produced. These are called as nicotinic effects because of their similarity to the action of nicotine. Accumulation of acetylcholine in the central nervous system produces restlessness, anxiety, insomnia, neurosis, tremor, ataxia, convulsions, depression of respiratory centers, and coma . The immediate cause of death in fatal OP poisoning is asphyxia resulting from respiratory failure. The usual symptoms of poisoning in man include: headache, giddiness, nervousness, blurred vision, weakness, nausea, cramps, diarrhea, slowing of the heart, and drop in blood pressure. Signs of poisoning include: sweating, salivation, lachrymation, vomiting, constriction of the pupil, uncontrollable muscular twitches, and in severe cases convulsions, coma, loss of reflexes, and death from respiratory failure. In Insects: Symptoms of poisoning in insects include restlessness, hyperexcitability, tremors (especially of the extremities), convulsions, paralysis, and death. The symptoms appear slowly and death may occur after several hours or up to 24 h. The ultimate cause of death is not certain but is regarded to be the result of cholinesterase inhibition by analogy with mammalian poisoning. In most insect species cholinesterase inhibition by OP compounds is not reversible. 147

The organo phosphate insecticides have three types of action (carbamates too have...) 1. Systemic action 2. Non-Systemic action 3. Intermediary / pseuedo-systemic / translaminar action Systemic action: • Systemic insecticide is one, which is capable of moving through vascular system of plants, irrespective of site of application, and poisoning the insects feeding on such plants . An insecticide that is absorbed into the tissues of a plant and repels or kills most or some kinds of the insects that feed upon it. One treatment is usually effective for weeks or months. Insecticide may be absorbed through root, leaf, stem, and translocated to various parts of treated plants . • These insecticides are called as plant systemics: eg: methyl demeton, dimethoate, phosphamidon, phorate, acephate, carbofuran (organo carbamate). • Animal systemics are those when applied either through orally or topically at dose does not harmful to animal, translocated to various parts of animal and kill the internal and external parasites. Eg: fenchlorphos (available in trade names such as runnel, trolene, etrolene etc.), chlorpyrifos (against cattle louse). • All systemic insecticides are stomach poisons. Application of systemic insecticides: Seed treatment (EC, WDP, WDG), broadcast in soil (granular form), spot application (granular form), furrow application (granular form), whorl application (granular form), foliar spray (WDP, EC, WDG). An ideal systemic insecticide should have: High insecticidal activity, Sufficient lipoid solubility for absorption by plant, Sufficiently soluble in water for proper translocation through vascular system of the plant, Stable in plant system for fairly long time to excercise residual action, but should be degraed to non-toxic forms in reasonable time to avoid toxicity to consumer. Uses: • Highly useful for controlling sap sucking insects and vectors of plant diseases such as leaf and plant hoppers, thrips, aphids, bugs, white flies etc. • Highly useful for controlling soil inhabiting insects, such as root grubs, cutworms. Advantages of systemic insecticides: • Longer persistence , as the toxicant has rapid penetration into plants and is not exposed to weathering. • Little or no effect on predators, parasites, pollinators , due to selective action. Hence they fit well in IPM. • Development of resistance is delayed as the surviving R strains are likely to be eaten by the predators of parasites. • Effective application even with less foliage • Minimal phytotoxicity • Acute toxic hazards due to spraying are minimized • Selective : effective against sucking insect pests • New foliage is also protected. Disadvantages: • Insects required to feed for longer time for taking lethal doses • Some are highly poisonous to man and other warm blooded animals • In plants after initial effective protection, resurgence of sucking pests is likey happen, example in case of aphids and jassids

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Examples of Systemic insecticides:

Acephate • Acephate is a foliar spray insecticide of moderate persistence with 75%SP residual systemic activity of about 10-15 days. • It is used for control of a wide range of biting and sucking insects , Asataf especially aphids, including resistant species, in fruit, vegetables Asraf (potatoes and sugar beets), vine, and hop cultivation and in Orthene horticulture (roses and chrysanthemums grown outdoors). Starthene • It also controls leaf miners, lepidopterous larvae, sawflies and thrips Lance in the previously stated crops as well as turf, mint and forestry. Pace • It is considered non-phytotoxic on many crop plants. • Acephate and its primary metabolite, methamidophos , are toxic to Heliothis spp . that is considered resistant to other OP insecticides. Methyl • Demeton-s-methyl replaces methyl demeton, a mixture of demeton-s- demeton methyl and demeton-o-methyl sold as Meta-Systox . 25%EC • Systemic and contact insecticide and acaricide . • It is absorbed and translocated within the plant in sufficient Metasystox concentrations to kill insects that feed on the plant by sucking its Hexasystox juices. It is used to control aph ids, sawflies, and spider mites in fruits, Dhanusystore vegetables, potatoes, cereals, ornamentals, and in forestry. • Demeton-s-methyl is more toxic to insects than demeton-o-methyl Dimethoate • Dimethoate kills mites and insects systemically and on contact. 30%EC • It is used against a wide range of insects, including aphids, thrips, planthoppers, and whiteflies on ornamental plants, alfalfa, apples, Rogor corn, cotton, grapefruit, grapes, lemons, melons, oranges, pears, Tara-909 pecans, safflower, sorghum, soybeans, tobacco, tomatoes, Tafgor watermelons, wheat, and other vegetables. Teeka • Used as a residual wall spray in farm buildings for house flies . • Dimethoate has been administered to livestock for control of botflies . Phorate 10G • Phorate is a systemic soil insecticide and acaricide used to control Thimet sucking and chewing insects, leafhoppers, leafminers, mites, some Foratax nematodes, and rootworms. Starphor • Popular insecticide among rice, groundnut, sugarcane farmers • Phorate is used in pine forests and on root and field crops, including corn, cotton, coffee, some ornamental and herbaceous plants, & bulbs. Monocrotophos • Monocrotophos is an insecticide and acaricide which works 36%SL,40%EC systemically and on contact . Nuvacron • It is extremely toxic to birds and is used as a bird poison. Azodrin • It is also very poisonous to mammals . Monocil • It is used to control a variety of sucking, chewing & boring insects, Monostar spider mites on cotton, sugarcane, peanuts, ornamentals, and tobacco. • It is banned for use on vegetables in India . Phosphamidon • Insecticide and nematicide with strong systemic action and stomach 85%SL action .

Dimecron, • Used against sucking pests, stem borers and aphids in cotton, paddy, Hydan and vegetables. Bilcran 85 149

Disulfoton • Disulfoton is a selective, systemic organophosphate insecticide and acaricide that is especially effective against sucking insects. • It is used to control aphids, leafhoppers, thrips, beet flies, spider mites, and coffee leaf miners. • Disulfoton products are used on cotton, tobacco, sugar beets, cole crops, corn, peanuts, wheat, ornamentals, cereal grains, and potatoes. Formothion • It is a systemic and contact insecticide and acaricide used to control 25EC spider mites, aphids, psyllids, mealy bugs, whiteflies, jassids, leaf Anthio miners, ermine moths, and fruit flies. • It is used on tree fruits, vines, olives, hops, cereals, sugar cane, rice.

Non-Systemic Insecticides: • Insecticides do not posess systemic action is called non-systemic insecticides. • They may have contact, stomach or fumigant action.

Quinalphos • Non-systemic insecticide and acaricide . 25%EC, • Quinalphos is a wide spectrum, contact and stomach insecticide with 1.5DP, 5%G, quick knock down effect . Ekalux, Flash, Suquin Dichlorvos • DDVP-Dichloro Dimethyl Vinyl Phosphate. (DDVP) • To control household, public health, and stored product insects . 76%EC, • It is effective against aphids, spider mites, caterpillars, thrips, and 100%SC white flies in greenhouse, outdoor fruit, and vegetable crops. Nuvan • Used to treat a variety of parasitic worm infections in dogs, livestock, Movan and humans. • It acts against insects as both a contact and a stomach poison. • It is used as a fumigant . • It brings quick knock down effect. • Highly toxic to bees. • Highly volatile, and does not leave toxic residues. Chlorpyrifos • Chlorpyrifos is a broad-spectrum insecticide. 20%EC • While originally used primarily to kill mosquitoes, it is suitable for Dursban indoor use for household pests and also animal houses. Rusban • Chlorpyrifos is effective in controlling cutworms, corn rootworms, Starban cockroaches, grubs, flea beetles, flies, termites, fire ants, and lice. Coroban • It is also effective against some sucking pests. • It is used as an insecticide on grain, cotton, field, fruit, nut and vegetable crops, and well as on lawns and ornamental plants. • Primarily as contact poison, with some action as a stomach poison. • It is popularly used against termites due to its persistence nature. It has fumigant action also. • Used for paddy seedling root dip @2% (1ml/1lt) against early pests of rice such as gall midge, leaf hoppers and gives protection for a month. It gets detoxified rapidly in mammals.

Phosalone 35% • It is used as both an insecticide and acaricide . EC, Zolone • It is best used in chilli for the management of both thrips and mites.

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Fenitrothion • Contact insecticide & selective acaricide of low ovicidal properties. 50%EC • Fenitrothion is effective against a wide range of pests, i.e. penetrating, chewing and sucking insect pests (coffee leafminers, locusts, rice stem borers, wheat bugs, flour beetles, grain beetles, grain weevils) on cereals, cotton, orchard fruits, rice, vegetables, and forests. Methyl • Methyl parathion is an organophosphate insecticide and acaricide Parathion used to control boll weevils and many biting or sucking insect pests 50%EC of agricultural crops, primarily on cotton. Metacid • It kills insects by contact, stomach and respiratory action Dhanumar

Pseudo-Systemic / Translaminar Insecticides: • Some non-systemic insecticides, howver, have the ability to penetrate plant tissues to varying extent and can move from one surface of leaf to another, are called pseudo- systemics / trans-laminar insecticides. • They are not true systemics. Eg: malathion, parathion, triazophos, profenofos

Triazophos • Acaricide, insecticide and nematicide. 40%EC • Controls sucking and chewing insects in cotton, rice, oil seeds and Hostathion vegetables, fruits and plantation, like tea, coffee and cardamom. Tarzan • In spite of being non-systemic, triazophos can penetrate deeply in the Traiumph plant tissues due to its translaminar properties and can effectively control leaf miner . Profenofos • Profenofos is a broad spectrum, foliar insecticide and acaricide with 50%EC contact and stomach action. Curacron • It is non-systemic but has an excellent translaminar action . • It is effective against a wide range of chewing & sucking insects and mites on Cotton, Rice, Maize, Sugar beet, Soybeans, Vegetables, Tobacco, Oil seeds and other crops. Parathion • First discovered by schradar. Parathion is a broad spectrum , pesticide used to control many insects and mites . • It has non-systemic, contact, stomach and fumigant actions with pseudo-systemic action. • It is activated into more toxic form paraoxon in plants. • It is extremely toxic to human. • Banned due to high mammalian toxicity. Malathion • Broad spectrum, Non-Systemic insecticide with contact and stomach 50%EC action and Respiratory action . • It also acts as Acaricide . It was one of the earliest organophosphate insecticides developed (introduced in 1950). • Malathion is suited for the control of sucking and chewing insects on fruits and vegetables, and is also used to control mosquitoes, flies, household insects , animal parasites (ectoparasites), and head and body lice. Diazinon • Persistant insecticide with nematicidal action.

5%G, 20%EC • It has contact, stomach, fumigant and penetrating action . • Used against pests of rice, fruit flies, mites and nematodes.

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Lecture: 23 Carbamates-mode of action-toxicity, formulations & uses of carbaryl, propoxur, carbofuran, aldicarb, methomyl-insecticides with nematicidal and acaricidal properties.

CARBAMATE INSECTICIDES: • Carbamates are organic compounds, esters of carbamic acid (NH 2COOH) and dithio carbamic acid with –OCON group in the structure. • Many of the carbamic esters are insectides , and few are molluscicides . • Carbamates insecticides act by a similar mechanism to organophosphate pesticides, but have a shorter duration of action . However, the recovery of poisoned insect from toxic dosage is normally rapid because carbamate insecticides are reversible choline esterage inhibitors . Like organophosphate pesticides, they interfere with the conduction of signals in the nervous system of insects, and in cases of poisoning with high levels of exposure, humans. • They are widely used, and have varying degrees of toxicity. • The efficacy of carbamate insecticides is very much increased by the addition of synergists like piperonyl butoxide (PBO) or propyl isome. • The carbamates are rapidly metabolized , and in mammals excreted through urine. • These compounds are most soluble in organic solvents. • Other carbamates are more aliphatic in nature and may possess sufficient miscibility with water to act as effective plant systemic insecticides (e.g., aldicarb).

Typical organo Carbaryl Carbofuran Propoxur carbamate structure where R 1 and R 2 are either hydrogen, methyl, ethyl propyl or other short-chain alkyls, and R 3 is either phenol, naphthalene, or other cyclic hydrocarbon rings. For example if R 1 is H; R 2 is CH 3 and R 3 is a phenyl ring, it is a phenylcarbamate (e.g. propoxur), or when it is replaced with naphthyl group, it is naphthylcarbamates (e.g. carbaryl).

History: As early as in the 17 th century the natives of the old Calabar region of southeast Nigeria, the Effiks, used the coffee-coloured Calabar beans, Physostigma venenosum in witchcrafts . The crushed bean called ‘esere’ was used as a poison ordeal to establish the guilt of a prisoner. The accused to be judged was forced to swallow the milky potion of crushed Calabar bean seeds in a small quantity of water. If the prisoner regurgitated the "milk" and survived he was declared innocent, but if he developed the symptoms of toxicity like shakes, froth at the mouth, and quickly died, he was declared guilty. The alkaloid from bean extract was identified as indole derivative of methyl carbamic acid in 1861 and was named “eserine” from the "esere”. A year later the alkaloid was isolated, purified and renamed physostigmine. During the same time miotic and cholinergic properties of physostigmine were discovered. The molecular structure was established in 1925 and the compound was synthesized in 1935. Stedman elucidated the structure of physostigmine and also synthesized a number of synthetic analogues of methylcarbamates some of which were toxic to many insect species. One of these, m- trimethylammoniumphenyl methylcarbamate, was toxicologically effective but was unstable in aqueous solution, and hence could not be used. The actual OC insecticidal moity was taken from the above chemicals, and then synthetic OC compounds were developed.

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Mode of action of organo carbamate insecticides: • Carbamate insecticides, like the organophosphorus compounds, inhibit acetyl choline esterase (AChE) by acting as a substrate for the enzyme, resulting in the accumulation of ACh in the nerve synapse, causing disruption of nerve function. • When a carbamate insecticide enters the synapse, it competes with acetylcholine for the active site on the enzyme. The insecticide binds to the enzyme and forms a complex with it. This complex is reversible and the enzyme could be dissociated from the carbamate (provided no further complexes are formed by the fresh molecules of the carbamate). However, in most cases the reaction proceeds to step 2 where the complex decomposes into a stable carbamylated (inhibited) enzyme and a leaving group. Finally, in step 3, the carbamylated enzyme is hydrolyzed to regenerate the free enzyme and methylcarbamic acid. Steps 2 and 3 are much slower with carbamates than with acetylcholine but are faster than those with OP compounds . • The enzyme which is inhibited by OP insecticides (the phosphorylated enzyme) is considerably less susceptible to hydrolysis (step 3) as a result, regeneration of the free enzyme is slow and recovery from OP poisoning is a much slower process . Symptoms of poisoning: • In general, in mammals, typical symptoms of poisoning by acute doses of carbamate insecticides are similar to those produced by OP compounds and include myosis, blurred vision, weakness, nausea, and vomiting, sweating, salivation, tearing, urination, pulmonary aedema, and convulsions. • Several carbamates are broad-spectrum insecticides and are toxic to many insect species, while others are more selective. Carbaryl, for example, has a wide range of toxicity to insects with LD 50 s ranging trom 0.1 to 1000 mg/ kg, but is practically nontoxic to the housefly. In insects the typical symptoms of carbamate intoxication are initial hyperactivity, followed by incoordinated movements (ataxia) and convulsions. • The antidote for carbamate poisoning is atropine (the same as that for OP insecticides). Atropine antagonizes the effect of excess acetylcholine which accumulated within the synapse by blocking the acetylcholine receptor sites, thus preventing continuous nerve stimulation. However, the antidote 2-PAM is not effective in accelerating the reactivation of cholinesterase (in some cases it might even be harmful); therefore, it should not be used as a therapeutic agent in human poisoning.

Examples: Carbaryl • Carbaryl is a wide-spectrum contact insecticide with little systemic 85%SP action which controls over 100 species of insects on citrus, fruit, cotton, 50%WDP forests, lawns, nuts, ornamentals, shade trees, and other crops, as well 4%G, 10%G as on poultry, livestock, and pets. Sevin • It is also used as a molluscicide and an acaricide . Hexavin • Especially effective against cotton pests. Orthene • It is not recommended for use on apples as it causes fruit drop . Starthene • It is used for control of human lice, animal ticks & mites (5%D) • Sevidol 4G (carbarly:lindane @1:1) used for rice pests. Propoxur • Propoxur is a non-systemic insecticide which was introduced in 1959. (Aprocarb) • It is compatible with most insecticides and fungicides 20%EC • It is used against chewing and sucking insects, ants, cockroaches, 5%G crickets, flies, and mosquitoes, and may be used for control of these in Baygon agricultural or (as Baygon) in non-agricultural (e.g. private or public Remover facilities and grounds) applications.

• It has contact and stomach action that is long-acting when it is in direct contact with the target pest.

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Carbofuran • Carbofuran is a broad spectrum systemic carbamate pesticide that kills 3%G insects, mites, and nematodes on contact or after ingestion . 50%SP • It is used against soil and foliar pests of field, fruit, vegetable, and Furadan forest crops. Furatox • Effective against soil inhabiting insects, sucking insects and also nematodes. • Useful for sorghum shootfly control. • It can be used as seed dresser . Aldicarb • Aldicarb, is an extremely toxic systemic insecticide . 10G • Used to control mites, nematodes, and aphids, it is applied directly to Temik the soil . • It is used widely on cotton, peanut, and soybean crops. • In the mid-1980s, there were highly publicized incidents in which misapplication of aldicarb contaminated cucumbers and watermelons and led to adverse effects in people. In 1990, the manufacturer of Temik (aldicarb), announced a voluntary halt on its sale for use on potatoes because of concerns about groundwater contamination. Methomyl • Methomyl was introduced in 1966 as a broad spectrum insecticide . 40%SP • It is also used as an acaricide to control ticks and spiders . Lannate • It is used for foliar treatment of vegetable, fruit and field crops, cotton, Dunet commercial ornamentals, and in and around poultry houses and dairies. It is also used as a fly bait . • It is popular against Spodoptera and other cutmorms as bait poison. • Methomyl is effective contact insecticide and systemic insecticide. • Methomyl 12.5%L is banned for use in India. Carbosulfan • Carbosulfan is systemic insecticide . 25%SD • Used for seed dresser for controlling sucking pests in many crops. Marshall • Foliar spray for sucking and chewing insects on many field and Tatafuran horticultural crops. • It is a good nematicide also.

Insecticides with nematicidal action: • Although the discovery of nematicidal activity in a synthetic chemical dates from the use of carbon disulfide (CS 2) as a soil fumigant in the second half of the nineteenth century, research on the use of nematicides languished until surplus nerve gas (chloropicrin) became readily available following World War I. • In the 1940s, the discovery that DD mixture (a mixture of 1,3-dichloropropene and 1,2-dichloropropane) controlled soil populations of phytoparasitic nematodes. • Ethylene di bromide (EDB), once the most abundantly used nematicides in the world, use of EDB was prohibited in the United States and other countries because of groundwater contamination. • Methyl bromide (MBR) is a broad-spectrum fumigant toxic to nematodes. In 1997, methyl bromide was the fourth most commonly used pesticide in the United States. It is agronomically useful against soil fungi, nematodes, insects, and weeds. It is being slowly withdrawn.

• The following are the insecticides with nematicidal activitiy: Neem cake, DBCP, EDB, DD mixture, Abamectin, Carbofuran, Carbosulfan, Aldicarb, Phosphamidon, Chlorpyrifos, Dimethoate, Phorate, Triazofos, and Fenamifos. 154

Insecticides with acaricidal action / miticidal action: • Acaricides are pesticides that kill members of the Acari group, which includes ticks and mites. • This class of pesticides is large and includes antibiotic acaricides, carbamate acaricides, formamidine acaricides, mite growth regulators, organophosphate acaricides, and many others. • From the Latin acarus, a mite + -cide, to kill. • Acaricides are used both in medicine and agriculture, although the desired selective toxicity differs between the two fields. • The following are the insecticides belong to various groups having acaricidal activity: Abamectin, DDT, Dicofol (Kelthane), Carbaryl, Carbofuran, Benomyl, Propoxur, Aldicarb, Chlorfenvinfos, DDVP, Chlorpyrifos, Methyl demeton, Dimethoate, Ethion, Malathion, Phorate, Quinalphos, Triazofos, Permethrin, Spiromesifen (Oberon) etc. • Wettable Sulphur is the best inorganic compound with acaricidal activity.

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Lecture: 24 Synthetic pyrethroids-brief mode of action-toxicity, formulations & uses of allethrin, resmethrin, bioresmethrin, bioallethrin, fenvalerate, permethrin, deltamethrin, cypermethrin, lambda- cyhalothrin, cyfluthrin, fenpropathrin, flucythrinate, fluvalinate, fenfluthrin .

• A pyrethroid is a synthetic chemical compound similar to the natural chemical pyrethrins produced by the flowers of pyrethrums ( Chrysanthemum cinerariaefolium and C. coccineum ). They are synthesized derivatives of naturally occuring pyrethrins, which are taken from pyrethrum, the oleoresin extract of dried chrysanthemum flowers. • Pyrethroids now constitute a major proportion of the synthetic insecticide market and are common in commercial products such as household insecticides . In the concentrations used in such products, they may also have insect repellent properties and are generally harmless to human beings in low doses but can harm sensitive individuals. They are usually broken apart by sunlight and the atmosphere in one or two days, and do not significantly affect ground water quality. • Pyrethroids are synthetic compounds based on natural pyrethrins with improved photostability and insecticidal activity . • The photostable pyrethroids have proven to be broad-spectrum insecticides , effective against a wide variety of insect pests, harmless to mammals and birds . They combine high insecticidal activity with suitable persistence . They are as much as ten times more effective in the field than the most potent compounds of the other three principal groups of insecticides, namely, the organochlorines, organophosphates, and carbamates.

History: As early as in 400 BC pyrethrum was used for louse control in Iran (Persia). The Chinese and the Japanese used several hundred years ago. Records show that in 1697, people on the Asian side of the Caucasus used the powder from the heads of pyrethrum flowers of local pyrethrum species ( Pyrethrum carneum and P. roseum ) as an insecticide. It was then discovered that Chrysanthemum cinerariaefolium had much higher concentration of the insecticidal principles. By 1840, commercial production of the dalmatian insect powder obtained from flowers of C. cinerariaefolium started in Dalmatia, a part of present-day Yugoslavia. Dried flowers and pyrethrum powder began to be exported to the United States in 1859. In the late 19th century, cultivation was started in Japan, which was the highest producer of pyrethrum till the Second World War. Between 1935 and 1940, Kenya replaced the Japanese product because it contained more pyrethrins per unit dry weight. Inspite of the fact that the synthetic analogues available now are more active and more stable, pyrethrum production has been steadily growing since 1948, since the synthetic analogues are more expensive than the natural compounds. Presently it is grown in Kenya, Tanzania, Rwanda, Ecuador and New Guinea with the East African countries accounting for almost 90% of the total world production. Pyrethrins are found in highest concentration at the time of full bloom. Hence careful handpicking of the flowers is necessary. This makes growing C. cineraefolium unprofitable for countries where the cost of labour is high. Originally pyrethrum was marketed in the form of finely powdered dried flowers . The flowers are extracted with an organic solvent (hexane), the extract is dewaxed and concentrated to contain about 20-25% pyrethrins. By partitioning with nitromethane, the petroleum solution is further concentrated to a viscous preparation containing about 90% pyrethrins.

The structures of the components of pyrethrum extract were recognized in early 1900s. Staudinger and Ruzicka in1924 isolated pyrethrin I and II and synthesized about 100 pyrethrin analogues , though none of these were insecticidal, but it laid the basis for the synthesis of many active compounds several decades later. The early pyrethroids merely served as pyrethrum substitutes and were mainly restricted to indoor applications because of their rapid degradation by ultraviolet light. Improvement of pyrethroid photostability was necessary to make them useful under field conditions.Synthetic 156

Pyrethroids were introduced by a team of Rothamsted Research scientists led by M. Elliott , and represented a major advancement in activity and relatively-low mammalian toxicity. Their development was especially timely with the identification of problems with DDT use. Their work consisted firstly of identifying the most active components of pyrethrum, extracted from East African chrysanthemum flowers and long known to have insecticidal properties. Pyrethrum rapidly knocks down flying insects, but has a low mammalian toxicity and negligible persistence - which is good for the environment but gives poor efficacy when applied in the field. Pyrethroids are essentially chemically stabilized forms of natural pyrethrum and belong to IRAC MoA group 3 (they interfere with sodium transport in insect nerve cells).

The 1 st generation pyrethroids, developed in the 1960s, include bioallethrin, tetramethrin, resmethrin and bioresmethrin . They are more active than the natural pyrethrum, but are unstable in sunlight. Activity of pyrethrum and 1st generation pyrethroids is often enhanced by addition of the synergist piperonyl butoxide (which is not itself biologically active). By 1974, the Rothamsted team had discovered a 2 nd generation of more persistent compounds notably: permethrin, cypermethrin and deltamethrin . They are substantially more resistant to degradation by light and air, thus making them suitable for use in agriculture, but they have significantly higher mammalian toxicities. Over the subsequent decades these were followed with other proprietary compounds such as fenvalerate, lambda-cyhalothrin and beta-cyfluthrin , but most patents have now expired, making them cheap and therefore popular. One of the less desirable characteristics, especially of 2nd generation pyrethroids is that they can be irritant to the skin and eyes, so special formulations such as capsule suspensions (CS) have been developed.

• In natural pyrethrums, the actual chemical ingredients having insecticidal properties are six biologically active keto-alcoholic esters derived from two acids ( chrysanthemic acid, pyrethric acid ), and three alcohols (pyrethrolone, cinerolone, jasmolone). • These acids are strongly lipophilic and rapidly penetrate many insects and paralyze their nervous system.

General Structure • The molecular structure of pyrethrins has a great potential for synthetic modification. • A large number of pyrethroids have been developed by modification of the structure of the natural pyrethrins. Several hundreds of pyrethroid molecules were synthesized and tested, and many of these showed enhanced photostability, faster knockdown, enhanced insecticidal potency, lower mammalian toxicity or a different insecticidal spectrum when compared with the pyrethrins. • The first synthetic modifications of the structure of pyrethrins mainly involved changes of the alcohol moiety. Allethrin, the first commercially available pyrethroid and still in use today, was derived from pyrethrin I by shortening the pentadienyl side- chain of the pyrethrolone moiety. • The pyrethrins and most of their synthetic analogues are viscous liquids with low vapour pressure with high boiling point , which prevents their environmental dispersion by air movements. They are highly lipophilic which favours their penetration in insect’s cuticule . Pyrethroids are also easily retained in the lipophilic cuticle of plant surfaces minimizing translaminar action in leaves and systemic movements in plants (non-systemic). Concentration of pyrethroids in the plant cuticle improves their rain-fastness and makes them useful in application as contact insecticides.

• Pyrethroids are toxic to fish and other aquatic organisms . 157

• Pyrethroids are axonic poisons and cause paralysis of an organism . The chemical causes paralysis by keeping the sodium channels open in the neuronal membranes of an organism. The sodium channel consists of a membrane protein with a hydrophilic interior; this interior is effectively a tiny hole which is shaped exactly right to strip away the partially charged water molecules from a sodium ion and create a thermodynamically favorable way for sodium ions to pass through the membrane, enter the axon, and propagate an action potential. When the toxin keeps the channels in their open state, the nerves cannot de-excite, so the organism is paralyzed.

• Pyrethroids are usually combined with synergist, piperonyl butoxide (PBO), a known inhibitor of key microsomal oxidase enzymes . This prevents these enzymes from clearing the pyrethroid from the body of the insect, and assures the pyrethroid will be lethal and not merely a paralyzing agent. Combined, pyrethroids are toxic to most beneficial insects such as bees and dragonflies. • A characteristic feature of pyrethroids is their negative temperature coefficient of toxicity in insects and poikilothermic animals. • In general, pyrethroids are degraded by the hydrolytic and oxidative processes, forming metabolites that are water soluble and thus can be conjugated and excreted.

Allethrin • Allethrin is a nonsystemic insecticide that is used exclusively in 4% homes and gardens for control of flies and mosquitoes . Jet mat • It is available as mosquito coils, mats, oil formulations, and as an Many aerosol spray . household • It has stomach and respiratory action and paralyzes insects before products killing them. • Another structural form, the d-trans- isomer of allethrin, is more toxic to insects, used to control parasites living in animal systems. Resmethrin • Resmethrin is a synthetic pyrethroid used for control of flying and Many crawling insects in homes , greenhouses, indoor landscapes, household mushroom houses, industrial sites, stored product insects and for products mosquito control. Krishinet • It is also used for fabric protection, pet sprays and shampoos , and it is applied to horses or in horse stables. 158

Bioresmethrin • Bioresmethrin is more toxic to houseflies and less toxic to rats. • Also used as grain protectant Fenvalerate • Insecticide and acaricide . 0.4%DP, • Contact and stomach poison. 20%EC • Less effective than cypermethrin. Fenval, Simicidin Fen-fen Permethrin • Widely used as an insecticide, acaricide, and insect repellent . 5%EC Permethrin is mainly used on cotton, wheat, maize, and alfalfa Ambush crops, and is also used to kill parasites on chickens and other Pounce poultry. • It is also extensively used in Europe as a timber treatment against wood-boring beetle . Deltamethrin/ • Contact and stomach insecticide . Decamethrin • It is used to control apple and pear suckers, plum fruit moth, 2.5%EC, 5%EC caterpillars on brassicas, pea moth, aphids, winter moth, codling Decis moths. Popularly used in cotton. Detlagaurd • Control of aphids, mealy bugs, scale insects, and whitefly on glasshouse cucumbers, tomatoes, peppers, potted plants, and ornamentals. Cypermethrin • Contact and stomach poison . 5% EC, • Effective against a wide range of pests in agriculture, public health, 10%EC, and animal husbandry. 25%EC • In agriculture, its main use is against foliage pests and certain Ripcord surface soil pests, such as cutworms, but, because of its physical Cymbush and chemical properties, it is not recommended against soil-borne cyperkill pests below the surface. • Popularly used in cotton. λ-cyhalothrin • Insecticide and acaricide used to control a wide range of pests in a 5%EC variety of applications, include aphids, Colorado beetles and 10%WP butterfly larvae in crops like cotton, cereals, hops, ornamentals, Karate, Matador potatoes, vegetables or others. Kung-fu • It may also be used for structural pest management or in public Sentry, Warrior health applications to control insects such as cockroaches, Demand mosquitoes, ticks and flies which may act as disease vectors. β-Cyfluthrin • Insecticide that has both contact and stomach poison action . 10%WP • It is a non-systemic chemical used to control cutworms, ants, Solfac silverfish, cockroaches, termites, grain beetles, weevils, Baythroid mosquitoes, fleas, flies, corn earworms, tobacco budworm, codling Tame moth, European corn borer, cabbageworm, loopers, armyworms, boll weevil, Colorado potato beetle, and many others. • Its primary agricultural uses have been for control of chewing and sucking insects on crops such as cotton, turf, ornamentals, hops, cereal, corn, deciduous fruit, peanuts, potatoes, and other vegetables.

• Cyfluthrin is also used in public health situations and for structural pest control 159

Fenpropathrin • Acaricide and insecticide with repellent and contact and stomach 10%EC action . Danitol • Uses Control of many species of mites (except rust mites) and insects (e.g. whitefly, lepidopterous larvae, leaf miners, leafworms, bollworms, etc.) on pome fruit, citrus fruit, vines, hops, vegetables, ornamentals (including ornamental trees), cotton, field crops, and glasshouse crops (cucurbits, tomatoes, ornamentals, etc.). Flucythrinate • Flucythrinate is a synthetic pyrethroid used to control insect pests in apples, cabbage, field corn, head lettuce, and pears, and to control Heliothis spp. in cotton, which is its primary use. Fluvalinate • Fluvalinate is a synthetic pyrethroid which is used as a broad 25%EC spectrum insecticide against moths, beetles and Hemipteran insect Mavrick pests on cotton, cereal, grape, potato, fruit tree, vegetable and plantation crops, fleas, turf and ornamental insects. • It has both stomach and contact activity in target insects Fenfluthrin • Insecticide for mosquito control. Bifenthrin • Insecticide and miticide . 10%EC Talstar, Capture Esfenavalerate • This is an s,s-isomer of fenvalerate Asana

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Lecture: 25 Insecticides of other groups-fixed oils; novel insecticides-nicotinoid insecticides-brief mode of action-toxicity, formulations & uses of imidacloprid, acetamiprid, thiamethoxam & clothianidin; phenyl pyrazoles-brief mode of action-toxicity, formulations & uses of fipronil.

Insecticides of other groups Fixed Oils: • Fixed oils are derived from plant (vegetable oils) or animal sources. • They possess insecticidal properties. • They are usually emulsified by the addition of soap, and then diluted. • They are not volatile. • Examples: Fish oil resin soap, neem oil, castor oil, linseed oil, soy bean oil, sesamum oil, citronella oil, Lemon eucalyptus oil, clove oil, peppermint oil, lemon grass oil, rose mary oil, fennel oil, garlic oil Fish oil resin soap (Rosin oil): • It is manufactured and commercially availalble in India. • It is used against aphids, thrips, whiteflies, scales, hairy caterpillars etc. • It acts as contact insecticide . • It is usually used @ 2.5% fish oil in soap. Neem oil: • Neem oil is a vegetable oil pressed from the fruits and seeds of neem Azadirachta indica • Natural cold pressed Neem Oil contains 0.003 to 0.007% azadirachtin. • Neem oil is generally light to dark brown, bitter and has a rather strong odour • It comprises mainly triglycerides and large amounts of triterpenoid compounds, which are responsible for the bitter taste. • It is hydrophobic in nature and in order to emulsify it in water for application purposes, it must be formulated with appropriate surfactants. • Formulations made of neem oil also find wide usage as a bio-pesticide for organic farming, as it repels a wide variety of pests including the mealy bug, army worms, aphids, thrips, whiteflies, mites, fungus gnats, beetles, moth larvae, mushroom flies, leafminers, caterpillers, locusts etc. • Neem oil also shows nematicidal activity . • Neem oil is known to be harmless to mammals, birds, earthworms or some beneficial insects such as honeybees, ladubugs. • It can be used as a household pesticide for ants, bedbugs, cockroaches, houseflies, termites and mosquitoes both as repellent and larvicide. • It is used @ 0.5-1%. Castor oil: • A natural mosquito repellent.

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Novel Insecticides: Neo-Nicotinoids: • Neonicotinoids are among the most widely used insecticides worldwide. • Neonicotinoids, the most important new class of synthetic insecticides of the past three decades, are used to control sucking insects both on plants and on companion animals. • Examples: Imidacloprid, thiamethaxam, acetamiprid, nitenpyram, thiacloiprid etc. • There are no records of cross-resistance to the carbamate, organophosphate, or synthetic pyrethroid insecticides, thus making them important for management of insecticide resistance. • As a group they are effective against sucking insects such as aphids, but also chewing insects such as coleptera and lepidoptera. • Recently, it was concluded that the insecticides of this group are toxic to bees. Mode of action: • The mode of action of neonicotinoids is similar to the natural insecticide nicotine, which acts on the central nervous system. • Imidacloprid (the principal example), nitenpyram, acetamiprid, thiacloprid, thiamethoxam, and others act as agonists (Ach agonist) at the insect nicotinic acetylcholine receptor (nAChR). The botanical insecticide nicotine acts at the same target without the neonicotinoid level of effectiveness or safety. Fundamental differences between the nAChRs of insects and mammals confer remarkable selectivity for the neonicotinoids. Whereas ionized nicotine binds at an anionic subsite in the mammalian nAChR, the negatively tipped (“magic” nitro or cyano) neonicotinoids interact with a proposed unique subsite consisting of cationic amino acid residue(s) in the insect nAChR. Knowledge reviewed here of the functional architecture and molecular aspects of the insect and mammalian nAChRs and their neonicotinoid-binding site lays the foundation for continued development and use of this new class of safe and effective insecticides.

• In insects, neonicotinoids cause paralysis which leads to death, often within a few hours. • They are much less toxic to mammals and under the WHO / EPA classification these compounds are placed toxicity class II or class III. • Because the neonicotinoids block a specific neural pathway that is more abundant in

insects than warm-blooded animals, these insecticides are selectively more toxic to insects than mammals. • They bind at a specific site, the post-synaptic nicotinic acetyl choline receptor. 162

Imidacloprid • In 1985, Bayer chemists synthesised for the first time. 17.8%SL • Because of its new mode of action, pests already resistant to other 70%WS/WG insecticides are controlled due to its excellent systemic properties. 30.5%WSC Farmers made these compounds the most successful insecticide 200SL world wide within a decade . 48%FS • Marketed in more than 120 countries protecting more than 140 2.5%Gel crops. It is possibly the most widely used insecticide , both within the mode of action group and in the worldwide market. Admire • Used for seed treatment, forrow treatment, and foliar treatment. It Atom is now applied against soil, seed, timber and animal pests as well as Gaucho foliar treatments for crops including: cereals, cotton, grain, Chemida legumes, potatoes, pome fruits, rice, turf and vegetables. Confidor • It has both contact and stomach action. Confidence • It is systemic with particularly effective against sucking insects and Nagarjuna mida has a long residual activity . • The application rates for neonicotinoid insecticides are much lower than older, traditionally used insecticides. • The biological spectrum includes broad range of target pests, such as sucking pests (ahpids, white flies, leaf hoppers, thrips, scales, mealy bugs etc.), coleoptera (leaf beetles, flea beetles, grubs), and others (leaf miners, termites, locusts). Thiamethoxam • Second generation neonicotinoid, synthesized by Syngenta 25%WG • Chemical structure is slightly different from other neonicotinoid 70%WS insecticides, making it highly water soluble and thus it is readily 30%FS translocated in plant tissue . Actara • Broad spectrum systemic insecticide with stomach & contact action Cruiser • Used for seed treatment and foliar application Platinum,Sitara • Effective against all types of sucking insect pests. Acetamiprid • Odorless neonicotinoid sysnthesized by Aventis crop science. 20%SP • Systemic insecticide for all types of sucking insects pests, with Assail contact, stomach action. Pride • It has low toxicity to human , cattle and little influence to the natural Rapid enemy of the insects, fish and bees. Ennova • With the special active mechanism, it can kill those insects which have resistance to organphosphorus and insecticides. Clothianidin • Developed by Takeda Chemical Industries and Bayer 50%WDG • Used for seed treatmenti and foliar spray Clutch • Broad spectrum systemic insecticide with contact & stomach action Dantop • Highly effective against BPH, GLH in paddy, and all other sucking pests in other crops. Nitenpyram • Insecticide used in agriculture and veterinary medicine to kill insect 10%SL,20%WDG external parasites of livestock and pets. Capstar Thiacloprid • Systemic insecticide, effective against all types of sucking insect 21.7%SC pests.

Splendour Dinotefuran Venom 163

Phenyl Pyrazoles: Fipronil and Ethiprole. Fipronil 5%SC, 0.3%GR, (Regent, Task) • Fipronil is an insecticide discovered and developed by Rhône-Poulenc between 1985- 87 and placed on the market in 1993. • Regent is a trademark for a broad spectrum systemic insecticide with contact and stomach action, containing the active ingredient fipronil. Regent's rights have been purchased by BASF. Actively marketed in many industrialised and developing countries its, worldwide use is increasing. Regent has contact activity on both chewing and sucking insects and controls Coleoptera, Lepidoptera, Diptera, Homoptera, Isoptera, and Thysanoptera. • Although effective against a variety of pests, there are concerns about its environmental and human health effects. • Disrupts the insect central nervous system by blocking the passage of chloride ions through the GABA (inhibitory neurotransmitter) receptor and glutamate-gated chloride channels (GluCl), components of the central nervous system. This causes hyperexcitation of contaminated insects' nerves and muscles. Insect specificity of fipronil may come from a better efficacy on GABA receptor but also on the fact that GluCl does not exist in mammals. • Fipronil is a slow acting poison. When mixed with bait it allows the poisoned insect time to return to the colony or haborage. • Fipronil not only controls insects effectively but also shows plant growth enhancement effect. Apart from the control of agricultural crop pests it can also be used for the control of household pests. Ethiprole 10%SC (Ethiprole) • Discovered by Bayer • Foliar, soil and seed treatment insecticide • Ethiprole blocks the gamma aminobutyric acid (GABA) regulated chloride channel in the insect central nervous system . • Ethiprole is not cross-resistant to other chemistry, thus Ethiprole is very well suited to control CNI resistant hoppers!

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Lecture: 26 Macrocyclic lactones-spinosyns-brief mode of action, toxicity, formulations & use of spinosad; avermectins-brief mode of action, formulationas & use of abamectin and emamectin benzoate; oxadaizines-brief mode of action, formulation & use of indoxacarb; thioureas- brief mode of action, formulations & use of diafenthiuron; pyridine azomethines-brief mode of action, formulations & use of pymetrozine; pyrroles-brief mode of action, formulations & use of chlorfenapyr and f lubendiamide.

MACROCYCLIC LACTONES: • The macrocyclic lactones are natural products ( naturolytes ), or chemical derivatives thereof, of soil microorganisms, actinobacterium , Streptomyces avermitilis (Avermectins & Milbemycins), and, Saccharopolyspora spinosa , (Spinsyns & its analogues ). Macrocyclic Lactones

Naturalytes of Soil Bacterium Naturalytes of Soil Bacterium, Streptomyces avermitilis Saccharopolyspora spinosa

Avermectins Milbemycins Spinosyns & its analogues

• The macrocyclic lactones have a potent, broad antiparasitic spectrum at low dose levels. They are active against many immature nematodes (including hypobiotic larvae) and arthropods . • The avermectins in commercial use are ivermectin, abamectin, doramectin, eprinomectin, and selamectin; Commercially available milbemycins are milbemycin oxime and moxidectin; Commercially available spinosyns is spinosad. Avermectins: • The naturally occurring avermectins are series 16-membered macrocyclic lactone derivatives . Avermectins are a group of fermentation products from a strain of Streptomyces avermitilis , a soil actinomycete, possessing potent anti-helmintic and insecticidal activities . Presently, avermectins are the active components of some insecticidal and nematocidal products used in agriculture. • Avermectins were first isolated at Merck Sharp & Dohme Resarch Laboratories in 1978 in Japan. 8 different avermectins were isolated in 4 pairs of homologue compounds with a major (a-component) and minor (b-component) component usually in ratios of 80:20 to 90:10. • Other anthelmintics derived from the avermectins include ivermectin, selamectin, doramectin and abamectin . • They have potent antihelmintic spectrum • They have potent insecticidal properties . • They are active against many immature nematodes (including hypobiotic larvae). • Avermectins effectively block GABA stimulated uptake and cause a release of chloride- channel dependent neurotransmitters .The avermectins block the transmittance of

electrical activity in nerves and muscle cells by activating voltage dependent membrane-bound proteins containing chloride channels.

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Abamectin: (1.9%EC) (Vertimec, Agrimec 1.9%EC) • The avermectins are insecticidal and anthelmintic compounds derived from various laboratory broths fermented by the soil bacterium Streptomyces avermitilis . Abamectin is a natural fermentation product of this bacterium. • Abamectin is widely used insecticide, acaricide and antihelminthic . • Abamectin is a mixture of avermectins containing more than 80% avermectin B1a and less than 20% avermectin B1b. These two components, B1a and B1b have very similar biological and toxicological properties. • Abamectin is used to control insect and mite pests of a range of crops , and also is used by homeowners for control of fire ants. • Abamectin is very specific against sucking insect pests such as thrips, hoppers, mites, and aphids. • Abamectin is also used as a veterinary antihelmintic. Emamectin benzoate: (5%SG) (Proclaim5%SG, Prabhav 5%SG, Nagarjuna Trust 5%SG)) • The benzoate salt derivative of abamectin B1. A mixture of emamectin B 1a (90%) and emamectin B 1b (10%), as their benzoate salts. • Emamectin benzoate (EB) is also used as an insecticide. • Discovery and initial development was by Merck & Co., Inc. (now Syngenta AG). First sales in Israel and Japan in 1997. • This new class of chemical is a highly potent, unique foliar insecticide that controls lepidopteran pests (caterpillars and worms) in cole crops, turnip greens, and leafy and fruiting vegetables. • EB is widely used in controlling lepidopterous pests in agricultural products in the US, Japan, Canada, and recently Taiwan and India. • The low-application rate of the active ingredient needed (~6 g/acre) • Broad-spectrum applicability as an insecticide has gained EB significant popularity amongs farmers. • Non-systemic insecticide which penetrates leaf tissues by translaminar movement . • Paralyses the lepidoptera, which stop feeding within hours of ingestion, and die 2-4 DAT. Spinosyns: (Tracer 45%SC-Dow) • Spinosyns are the family of natural products (naturolytes) that possesses extraordinary insecticidal activity. • Spinosad (spinosyn A and spinosyn D) are a new chemical class of insecticides that are registered to control a variety of insects. • The active ingredient is derived from a naturally occurring soil dwelling bacterium called Saccharopolyspora spinosa. The bacteria produce compounds (metabolites) while in a fermentation broth. The first fermentation-derived compound was formulated in 1988. • Spinosad has a unique mode of action that is different from all other known insect control products. Spinosad acts as acetylcholine receptor modulator by altering acetylcholine receptor site and by disrupting binding . Spinosad causes rapid excitation of the insect nervous system, leading to involuntary muscle contractions, prostration with tremors, and finally paralysis. These effects are consistent with the activation of nicotinic acetylcholine receptors by a mechanism that is clearly novel and unique

among known insecticidal compounds. Spinosad also has effects on GABA receptor function that may contribute further to its insecticidal activity. 166

• Due to this unique mode of action, Spinosad is valued in resistance management programs. • Spinosad must be ingested by the insect (stomach poison) , therefore it has little effect on sucking insects and non-target predatory insects. • Spinosad is relatively fast acting. The insect dies within 1 to 2 days after ingesting the active ingredient. • It is highly effective even at low doses . • It is active by contact and ingestion exposure . • Spinosad is a broad-spectrum insecticide used to control Lepidoptera larvae (caterpillars), Diptera (flies), Thysanoptera ( thrips ), Coleoptera (beetles) and many other crop-damaging pests. • Spinosad is registered for use in over 82 countries for more than 250 crops • Less impact on predatory insects. OXADIAZINES • Indoxacarb 15%EC (Avaunt) • A potent blocker of sodium-dependent action potentials in lepidopterans (voltage dependant sodium channel blocker-interferes with a group of ion channels by inhibiting the flow of sodium into nerve cells causing paralysis and death of pests). • Indoxacarb is a pesticide that acts against lepidopteran larvae . • Broad spectrum insecticide. • Stomach and contact poison. • Inhibit feeding immediately and death. • Active at low doses • Safe to predators and other beneficial insects. • Low mammalian toxicity THIOUREA DERIVATIVES: • Diafenthiuron 50%WP (Pegasus) • A new class insecticide and miticide . • Diafenthiuron (a thiourea insecticide/acaricide) is proposed by scientists at Ciba-Geigy to act in insects as a mitochondrial adenosine triphosphatase (ATPase) inhibitor following metabolic activation to the corresponding carbodiimide (a metabolite). • Insecticide and acaricide which kills larvae, nymphs and adults by contact and/or stomach action ; also shows some ovicidal action . • Insecticide and acaricide effective against phytophagous mites, white flies, aphids and Jassidae on cotton, various field and fruit crops, ornamentals and vegetables. • Also controls some leaf-feeding pests in cole crops, soya beans and cotton. • Applied at 300-500 g/ha. • Is safe on adults of all beneficial groups, and on adults and immature stages of predatory mites, and Chrysopa carnea . PYRIDINE AZOMETHINES: • Pymetrozine 50%WDG (Endeavor, fulfill) • Pymetrozine, a pyridine azomethine, represents a new chemical class of insecticides • Pymetrozine is a neuroactive insecticide (selectively affecting chordotontal mechanoreceptors) but its site of action in the nervous system is unknown. • New insecticide with a remarkable selectivity for plant-sucking insects , such as aphids, whiteflies and plant hoppers, due to its systemic action. • This fairly narrow biological spectrum seems to be related to a novel mode of action.

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PYRROLES: (Chlorfenapyr and Flubendiamide) Chlorfenapyr • Phantom, Lepido 10%SC • Pyrroles, a five membered heterocyclic ring compounds with odour similar to chloroform . • Chlorfenapyr is a pyrrole insecticide first commercialized for the control of agricultural pests and termites . • Chlorfenapyr is an insecticide, and specifically a pro-insecticide (meaning it is metabolized into an active insecticide after entering the host), derived from a class of microbially produced compounds known as halogenated pyrroles. • Chlorfenapyr works by disrupting the production of Adenosine triphosphate (ATP), specifically, "Oxidative removal of the N-ethoxymethyl group of chlorfenapyr by mixed function oxidases forms the compound CL 303268. CL 303268 uncouples oxidative phosphorylation at the mitochondria, resulting in disruption of production of ATP, cellular death, and ultimately organism mortality." • Registered for use on cotton . • Slow acting insecticide . • Used against termites . Flubendiamide • 20%WDG, Takumi, 480SC, Fame • The first insecticide which activates ryanodine receptors (which regulates calcium channel at post-synaptic/neuro-muscular junction) on insects. • In contrast to most insecticides which act on the nervous system, flubendiamide disrupts the proper muscle function in insects by acting on the ryanodine receptors . • Flubendiamide treated insects show rare symptoms of poisoning, which result in complete and irreversible contraction paralysis. These symptoms induced by flubendiamide, suggest that flubendiamide interacts with a site distinct from the ryanodine binding site and disrupts the calcium regulation of the ryanodine receptor completely by an allosteric mechanism. • Originally discovered by Nihon Nohyaku researchers and developed jointly with Bayer Crop Science. • Recommended for use on lepidopteran pests . • Stomach insecticide • Registered in India during 2007. • Requires very less dose for the insect pest management • Less mammalian toxicity • Less harmful to beneficial insects. Notes:

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Lecture: 27 Formamidines- brief mode of action, formulations & use of chlordimeform & amitraz; ketoenols- brief mode of action, formulations & use of spirotetramat, spiromesifen & spirodiclofen.

FORMAMIDINES: • A new group of acaricidal insecticidal compounds , used as plant sprays and topically on animals. • Examples: Chlordimeform (CDM), Amitraz • Their biological activity and uses are defined by their toxicity to spider mites, ticks, and certain insects and they are particularly effective against juvenile and resistant forms of these organisms. • At sublethal levels they cause behavioural changes in the target pest species (for example in feeding and in mating behaviours), changes which are responsible for the protective effects on crops and livestock. • Although many reported underlying biochemical mechanism, including inhibition of monoamine oxidase activity, uncoupling of respiration and blockade of neuromuscular transmission, recently, interaction with octopamine receptors in the central nervous system is also reported. Chlordimeform (CDM): • Chlordimeform is an acaricide and is active against mites and ticks. • Chlordimefrom is an insecticide and effective against eggs and early instars of some lepidoptera insects . • It also acts as very good anti-feedant. • Its use has ceased and its registration has been withdrawn in most countries due to its carcinogenic activity. Amitraz (Mitaban 19%EC) • It is an insecticide and acaricide used to control red spider mites, leaf miners, scale insects and aphids. • Sedation, analgesic effects and cardiovascular depression are the main symptoms. • On cotton it is used to control bollworms, whitefly and leaf worms. • On animals it is used to control ticks, mites, lice and other animal pests . • Very popular veterinary drug. • The US-EPA classifies amitraz as Class III - slightly toxic.

KETOENOLS: Spiromesifen (Oberon 240SC) • Spiromesifen belongs to the chemical class of ketoenols invented by Bayer. • Very unique mode of action through inhibition of lipid bio-synthesis and acetyl- CoA- carboxylase. • Extremely effective against broad spectrum of sucking insects . • Also show acaricidal activity. • Non-systemic insecticide with translaminar action. • Stomach poison with some contact action. • Effects egg and immature stages of white flies, aphids, thrips, jassids and other sucking insects including mites.

• Less effect on beneficial predatory insects. • Registered for use in India during 2009.

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Spirotetramat • Spirotetramat belongs to the chemical class of ketoenols invented by Bayer. • Very unique mode of action through inhibition of lipid bio-synthesis and acetyl- CoA- carboxylase. • Extremely effective against broad spectrum of sucking insects . • Spirotetramat is a long-acting active ingredient which protects pome and stone fruit, citrus fruit, grapes, nuts, vegetables and potatoes from pests such as aphids, cicadas, grape louse, mealy bug, whitefly and cottony cushion scale. • The unique feature of this substance is that the systemic active ingredient moves up and down through the entire plant system, including the young shoots, leaves and roots, and is thus distributed evenly and lastingly. • It acts against insect larvae by ingestion (stomach poison). • Not yeat registered in India. Spirodiclofen • Spirodiclofen belongs to the chemical class of ketoenols invented by Bayer. • Spirodiclofen is a selective , non-systemic foliar insecticide and acaricide . • Very unique mode of action through inhibition of lipid bio-synthesis and acetyl- CoA- carboxylase. • Extremely effective against broad spectrum of sucking insects . • Not yet registered in India

Notes:

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Lecture: 28 Chitin synthesis inhibitors-brief mode of action, formulations & use of diflubenzuron, flufenoxuron, chlorfluazuron, triflumuron, teflubenzuron, lufenuron, hexaflumuron, flucyclouron, novaluron & buprofexin.; juvenile hormone (JH) mimics- brief mode of action, formulations & use of juvabione, methoprene, hydroprene, kinoprene; JH agonists- brief mode of action, formulations & use of pyriproxyfen, fenoxycarb; ecdysone agonists- brief mode of action, formulations & use of methoxyfenozide, halofenozide & tebufenozide.

INSECT GROWTH REGULATORS (IGRs): • IGRs (Insect Growth Regulators) are the insect hormones (or their synthetic mimics) that govern an insects maturation process. When used as pesticide, IGRs stop insect larva from developing into biting, reproducing adutls. • Growth inhibitors or Insect Growth Regulators (IGR) are products or materials that interrupt or inhibit the life cycle of a pest. If an animal cannot reach adulthood, it is not capable of reproducing. By inhibiting the maturity of an insect, we keep it from reaching the critical adult stage, thus stopping the life cycle and infestation. In layman's terminology, an IGR is not an insecticide (in the bug killing definition) but is a man-made protein that only affects certain insects or groups of insects. • Insect Growth Regulators (IGRs) are one of the fastest developing chemical classes of insecticides in the past ten years. • The first IGRs were developed in the 1960’s but most that are used today are new products. • They are considered as reduced risk pesticides because they are soft on beneficial insects and primarily are target specific for juvenile stages . • These products do not work on the insect nervous system like classical insecticides and are therefore more worker-friendly within closed greenhouse environments. General Information: • For an insect to molt to the next stage, the correct ratio of juvenile hormone and ecdysone must be present. Ecdysone is a primary molting hormone that is necessary for insects to go from the larval to pupal stage. • If you change the ratio of one to the other, the insect will not become an adult-thus reducing reproduction and population increase. With some IGRs, adults will form but fail to produce viable eggs. • Since insects molt many times, the ability to create chitin is vital to form the insect’s exoskeleton. Without the proper cuticle (exoskeleton), the insect will die. Chitin synthase is an important enzyme responsible for the systhesis of chitin in insects, and hence chitin synthesis inhibitors affect insects, and also work for a longer period of time than the hormonal types of IGRs. These are also quicker acting but can affect predaceous insects, arthropods and even fish. • With these principles, Chitin synthesis inhibitors (CHIs) and Hormonal Mimics/Analogues/Agonists are explored for insect pest management in IPM programmes, due to their specificity, environmental friendly, non-toxic to higher animals, less residues characters. • Generally, Hormonal IGR’s may take as long as one generation (3-10 days depending on the insect and the weather) to work so they are best utilized early in the crop when populations are low and are not a good rescue treatment when outbreaks are severe,

but CHIs work for a longer period of time than the hormonal types of IGRs. • The most effective way to incorporate IGRs in a Pest Management program is to start early or tank mix with a “knock-down” insecticide (adulticide) like a pyrethroid. If 171

there is a high population of pests, especially if they are adults, use the adulticide then the IGR a week later. It is a good idea to rotate within the IGR class since many insects will be affected by all three modes of action and as with other insecticides, rotation will help control possible resistance. • Azadirachtin is the active ingredient of many IGRs is the primary chemical that is so close to ecdysone that the natural hormone is blocked. Adding horticultural oils to the spray will make azadirachtin work better. Short-lived insects like whiteflies are controlled best.

Insect Growth Regulators (IGRs)

Chitin Synthesis Inhibitors Insect Hormones Disruption (CSIs) (Disrupt the ratio of growth regulating Hormones)

Juvenile Hormone Analogues

JH mimics / analogues

JH agonists

Ecdysone Analogues

Ecdyso ne mimics / analogues

Ecdysone agonists

Chitin Synthesis Inhibitors (CSIs): • Chitin is biopolymer of N-acetylglucosamine, linked by b-(1-4)- glycosidic bonds, that are joined in a reaction catalyzed by membrane-integral enzyme chitin synthase in nature. It is mainly produced by fungi, arthropods and nematodes. In insects, N- acetylglucosamine is synthesized from an insect specific aminoacid-trehalose, and the chitin is synthesized from N-acetlyglucosamine catalyzed by chitin synthase. • In insects, it functions as scaffold material, supporting the cuticles of the epidermis and trachea as well as the peritrophic matrices lining the gut epithelium. • Insect growth and morphogenesis are strictly dependent on the capability to remodel chitin-containing structures. For this purpose, insects repeatedly produce chitin synthases and chitinolytic enzymes in different tissues. Coordination of chitin synthesis and its degradation requires strict control of the participating enzymes during development. • There are many synthetic chemicals which can interfere with chitin synthesis, majorly through inhibition of chitin synthase . • Benzoylphenylureas (BPUs) is the major group with CSIs activity. 172

Diflubenzuron • Halogenated benzoylphenylurea (BPU) IGR. 25%WP • The insecticidal activity of BPUs discovered in early 1970s. 45%DC • Posesses high selectivity, low mammalian toxicity, high 48%SC biological activity, rapid degradation in soil and water. Dimilin • Stomach and contact insecticide. • Non-systemic insect growth regulators for control of a wide range of leaf-eating insects and their larvae in vegetables, pome fruit, and mushroom. Sucking insect pests are not directly affected due to its non-systemic action. • It is classified as restricted use pesticide in USA. • Mainly used for the control of mosquitoes . Novaluron • BPU IGR with contact action. 10%EC • Best used against diamond backed moth in cabbage, Heliothis Rimon (Indofil) and Spodoptera in various crops. Flufenoxuron • BPU IGR 10%DC / EC • Insecticide and Miticide / Acaricide Cascade (BASF) • Effective against lepidopteran larva and mites. Lufenuron • BPU IGR 5%EC • Insecticide and Miticide / Acaricide Match (Syngenta) • Best used in veterinary flea control. Signa (Syngenta) • Effective against lepidopteran larva and mites. • Lufenuron is an insect growth regulator for control of Lepidoptera and Coleoptera larvae on cotton, maize and vegetables; and citrus whitefly and rust mites on citrus fruits. Chlorfluazuron • BPU IGR 0.1% termite bait • It can effectively control a wide range of Lepidoptera, Requiem (PCI) Orthoptera, Coleoptera, Hymenoptera, Diptera insects on Cotton, Soybean, Corn, Vegetables, Fruit tree, Tea, Potato, and Tobacco etc. • Also it is harmless to most beneficial insects. • PCI 0.1% termite bait formulations are used for termite colony elimination from buildings. Chlorbenzuron • BPU IGR 25%SC • Not yet registered in India. Triflumuron • BPU IGR 480SC • Recommended for lepidopteran larvae Starycide (Bayer) • Used for mosquito control Buprofezin • Thiadiazine IGR against coleoptera, hemiptera and acarina. 25%EC • Largely used for the control of BPH in paddy . Applaud (Rallis) • Most successful IGR against plant hoppers, white flies and Blunt (Jayasri) scales. • Best suitable in IPM programs. Cyromazine • Triazine IGR used as insecticide and acaricide. 50%SP, 2%SG

• Used in animal health care for the control of fly larvae Neporex (Novartis)

173

JH mimics:

Paper Factor : In 1965, Sláma and Williams made a surprising discovery that paper towels made from the wood of the balsam fir (Abies balsamea ) released vapors that elicited a potent effect on hemipteran bugs ( Pyrrhocoris apterus ) of the Pyrrhocoridae family. They coined this substance as " the paper factor ." When reared in contact with "active paper" or extracts prepared front active paper, larval Pyrrhocoris undergo one or more supernumerary larval moults and finally die without completing metamorphosis or attaining sexual maturity . This 'factor' was thought to contain a mixture of JH- mimicking sesquiterpenes, but it wasn't until 1966 that (+)-juvabione was first isolated as an active component from the balsam fir by Bowers .

• In some insects (hemi-metabolous or exo-pterygotes), the final molt produces an adult that looks pretty much like the earlier larval stages (nymphs). In others, like moths and butterflies, the final molt of the larva (caterpillar) produces a pupa. After a period of metamorphosis, the adult moth emerges. Ecdysone triggers larva-to-larva molts as long as another hormone, called juvenile hormone (JH), is present. In its absence, ecdysone promotes the pupa-to-adult molt. Thus normal metamorphosis seems to occur when the output of JH diminishes spontaneously in the mature caterpillar. • When solutions of JH (JH mimics or JH agonists) are sprayed on mature caterpillars, or on the foliage upon which they are feeding, their normal development is upset . This raises the possibility of using JH as an insecticide (one that might avoid the problem of developing resistance). As it turns out, JH is too unstable to be practical, but some synthetic JH mimics like methoprene (Altosid®), kinoprene, hydroprene, and JH agonists like pyriproxyfen (Esteem®, Knack®, Distance®), fenoxycarb, and diofenolan, are now being used.

Insect Growth Regulators (IGRs)

Insect Hormones Disruption (Disrupt the ratio of growth regulating Hormones)

Juvenile Hormone Analogues

JH mimics / analogues

Naturally occurring JH mimics Synthetic JH mimics

JH agonists

Ecdysone mimics / analogues / agonists

Plant based

Synthetic

Naturally occurring IJHMs (Insect JH mimics): • Juvabione is the naturally occurring sesquiterpenes found in the wood of Abies , and

sesquiterpenes of this family are known as insect juvenile hormone analogues (IJHA), because of their ability to mimic juvenile activity in order to stifle insect reproduction and growth. 174

Synthetic JH mimics / analogue: • Methoprene: (Altosid®): A JH analogue, used as IGR. Non-toxic to humans. It doesnot kill adult insects, instead act as IGR mimicking natural JH. JH must be absent in pupa to molt to adult, so methoprene treated larva will be unable to successfully change from pupa to adult. Methoprene is most widely used as mosquito larvicide . • Kinoprene (used against whiteflies, scales and mealybugs) • Hydroprene (Hydroprene is not photo-stable, and hence is used only in indoors): Best used against cockroaches, beetles and fleas . Synthetic JH agonists: • Pyriproxyfen : (Esteem®, Knack®, Distance®): Pyriproxyfen is a pyridine based pesticide which is found to be effective against a variety of arthropoda. It was introduced to the US in 1996 to protect cotton crops against whitefly. It has also found use protecting other crops and can also be used as a treatment for cat fleas . Most effe ctive larvicide used as veterinary drug. • Fenoxycarb (5%EC, 5% SP, 25%WP- Torus, Award). It is a carbamate insect growth regulator . Fenoxycarb has an insect-specific mode of action exhibiting strong juvenile hormone activity . It inhibits metamorphosis to the adult stage, induces interference with the molting of early instar larvae, and produces certain ovicide and delayed larvicide/adulticide effects in various insect species. It is used as fire ant bait and for flea, mosquito and cockroach control. Fenoxycarb can also be used to control butterflies and moths (Lepidoptera), scale insects, and sucking insects on olives, vines, cotton and fruit. It is also used to control these pests on stored products. Low toxicity to bees, birds and human. Precocenes: • First discovered in plants, these damage the corpora allata thus preventing juvenile hormone (JH) from doing its normal job. • Applied to early larval stages, precocenes induce premature or precocious metamorphosis (like that induced by the surgical removal of the corpora allata. Not only does precocious metamorphosis cut short the destructive larval phase of the insect, but the adults are abnormal (besides being small). • The females, for example, are sterile (because JH is needed for development of the ovaries). • The natural precocenes are available in Ageratum conyzoides. Ecdysone agonsits: Insect growth and development involves many stages of shedding its hard outer cuticle–a process termed as metamorphosis (ecdysis). The hormone controlling this process has been therefore called ecdysone . These steroidal hormones were isolated and characterized by A. Butenandt and P Karlson in 1954 from Bombyx mori (silkworm moth). From 500 kg of this female insect, they isolated 25 mg of the hormone. Ecdysone is today known as a pro-hormone, as the real hormone 20-hydroxy ecdysone is formed inside the insect’s body by a stereo-specific hydroxylation at position 20 in the steroid skeleton. Cholesterol is converted in the insect’s body to these hormones. However, insects lack the ability to make cholesterol and they must necessarily take it from outside. They get it from the plants by breaking down molecules like sitosterol. • Plants like spinach contain phytoecdysones (plant-based ecdysones). This could bring about multiple molts in the insect. • Based on the chemical structure of ecdysone (natural insect growth hormone), many synthetic chemcials were tried for their insecticidal action. The following are some:

Methoxyfenozide, Halofenazide, Tebufenazide.

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Lecture: 29 Recent methods of pets control- repellants (physical and chemical repellents); antifeedants- importance of antifeedants and limitations of their use; sex pheromones-definition, list of pheromones available-use in IPM; insect hormones-moulting and juvenile hormones; gamma radiation- principles and limitations; genetic control- principles and its limitations; sterile male technique .

• Like human, insects are sensitive to several input of environment, these being radiation (heat and light), movement and pressure (including sound) and chemicals so all those factor is important to insect detected the host. • Insects are attracted to flower by different stimuli and slight modification result in specificity of this relationship. Petal color of yellow green, blue, purple, or those that reflect or absorb high amounts of ultraviolet light are especially attractive. Related to the host chemical that be produced, doing by direct contact with the molecules or ions of chemical in solution concentration usually somewhat higher than olfactory chemostimuli . Chemical from environment are useful to insect in several ways, for example food (host plant or animals, prey decaying organic matter, and so on) procurement, mediation of caste function in social form, mate location, identification of noxious stimuli that are potential threat to survival, selection of oviposition site, habitat selection and others. Host of insect usually had the special chemical matter that insect can sense. • Most insect behavior is genetically programmed, or innate. A caterpillar with no prior experience or instruction can still spin a silken cocoon. But can an insect change its behavior as a result of its experiences? In other words, can insects learn? You won't see one graduating from Harvard anytime soon, but indeed, most insects can learn. "Smart" insects will change their behaviors to reflect their associations with and memories of environmental stimuli. The insect orients itself by responding to the stimuli it receives . All the activities (stimuli reception and action there on) are coordinated by nervous system. Insect behavior is usually described as a series of movements in response to stimuli. Insect orientation is the capacity and activity of controlling location and attitude in space and time with the help of external and internal stimuli, such as chemical orientation, gravity orientation, color orientation, positional orientation, orientation to light, orientation to smell etc.. • Many insect species posses the ability and behavior of orientation. Intensive studies have been performed on orientation behavior of some social and migratory insects. Results indicated that there are several possible orientation cues of migratory insect, such as sun compass, magnetic compass, celestial compass, wind and landmark cues. Entomological radar, electromagnetism and molecular techniques have played important role in revealing the orientation mechanism of insects. Social insect posses the ability of precise navigation by integrating various orientation cues. Day- flying insects can use the time-compensate sun compass perform orientation, but the orientation mechanisms of nocturnal migratory insects still need to make further researches. To clear the mechanisms of migratory pest insects will greatly help to determine their flight track and possible landing area, so as to provide a basis for insect pest forecasting. • Host-plant finding is affected by both the distribution of host plants and the insect's orientation which is described as a control system. Orientation is controlled by internal information as well as by external information. The input-output relations of control systems depend on the existence of subsystems (nervous and motor system) and the form of their connections (the control pattern). The equilibrium between external and internal information determines the output locomotion patterns. Walking patterns of Colorado potato beetles vary from convoluted tracks. The internal state of the beetle, being starved or satiated, is decisive for setting the equilibrium between external and internal control. • In most insects, orientation with respect to gravity involves propioreceptors, similarly many aquatic insects have pressure receptors for balance maintenance. • The orientation and behaviour of insects depends largely on host plants, natural enemies, weather parameters, etc. Insect behaviour is studied in relation to biotic and abiotic factors. Knowledge of insect behaviour is manipulated for insect control. Behavioral components are especially important

during host finding and acceptance of a pest. Behaviour of an insect pest is inturn affected by the physical and chemical characteristics of its host plant in general and volatiles, which act as

attractants, repellents, deterrents, stimulants in particular that, regulate the insect behaviour. In 176

management of pests in an agro-ecosystem, one should take into consideration the number, abundance and distribution of pest species and their biological and behavioural characteristics. The insects orient themselves to the food, lures, light, etc., which can be efficiently utilized for integration in pest management. • Generally, during the first stage of search for suitable host , the initial attraction of insect to their food from a distance is often not very specific, it can occur by visually or olfaction depends on the situation and also species. Visually there are some important cues, such as colors, shape, sight of solid object, pattern of any form . Locust recognize the host in a distance by pattern of vertical stripes that mimic to grassy habitat they prefer, also Heliconius butterflies recognize the host initially by leaf shape, while the using of colors also play a part in recognition, such apple maggot flies attract to yellow surfaces, bees and many insect feed on flower also depend on color as initial recognition. • In the next stage of settling on the host plant , due to general lack of specificity in visual factor, olfaction start to play an important role in this stages to recognize some volatile chemical released by the host plant , but it occur over a relatively short distance, because odour gradients and plume are unlikely to be very well define in the field. This chemical frequently can be used by insect to distinguish between the odor of many plant species even when the volatile substances are closely related chemically. • After identification of plant species, the final stages for the insect whether they will accept the plant as a host or not . For some insect like aphid this is the only determining stage after they landed randomly. In this stages the insect start to make actual contact with the plant in order to recognize the suitability for their feeding and oviposition, Usually it occurs at closer quarters and involves different stimuli, generally gustatory are important for continued feeding but sometimes it combined with olfaction and visual stimuli. • The process of host plant selection by insects is a lock and key system , in which the lock refers to the host plant and the key refers to the complex sensory pattern of the insect. Only when this pattern corresponds to some innate standard is an appropriate behavioral respond triggered. The host plant recognition process is not a simply a matter of responding to a kairomone or allomone, but it is a result of integration of numerous plant chemical and insect internal factor. Studies of lepidopterous larvae have indicated that insect host recognition and acceptance are based upon complex mixed olfactory and gustatory sensory information. Although a particular compound may dominate the chemical composition of a plant and may contribute the major sensory cue, it is the total chemical complex that forms the basis perception. • So, the relations between pest and their host are influenced by two aspects: the insect aspect and the plant aspect . Physiological characteristics influencing insects usually involve chemicals which are produced from primary and secondary metabolic processes. The results of primary metabolic processes in plants produce such as enzymes, hormones, carbohydrates, lipids, proteins, and phosphorus compounds. For insects, some of these primary metabolites are feeding stimulants, nutrients, and toxicants. The results of secondary metabolic processes which have correlation to promote communication between members of different species (insects-plants) are called allelochemics . • For example, carbon dioxide given off by humans and other animals is used as a kairomone by female mosquitoes seeking a blood meal. For example, secretions that deter predators are allomones . A single chemical signal may act as both a pheromone and a kairomone ; for example, the compounds emitted by a bark beetle colonizing a host tree attract other bark beetles (functioning as an aggregation pheromone), but the same compounds also attract certain predators and parasites that attack these bark beetles (functioning as a feeding attractant or kairomone). • Chemicals that act as attractants or carry other messages across distances are volatile (quick to evaporate) compounds. When released into the air, they can be detected by certain insects (those receptive to a specific compound) a few inches to hundreds of yards away. Chemicals that carry messages over considerable distances are most often used in pest management . • So, the attraction, repellency, stimulation, deterrence etc are mediated by chemicals from exocrine system of the interacting individuals, and these mediating chemicals are collectively called

semiochemicals , and intra-specific communication chemicals of this group are called pheromones. Understanding the role of such chemicals help us to use these chemicals for pest management purposes. 177

Semiochemicals (Gk. semeon , a signal) are chemicals that mediate interactions between organisms. Insects use many different semiochemicals , chemicals that convey messages between organisms or mediate interactions between organisms.

Allelochemicals Pheromones (Inter-Specific) (Intra-Specific) Allelochemicals are chemicals (Gk. phereum , to carry; that are significant to individuals horman , to excite or stimulate) of a species different from the are the chemicals released by source species. one member of an insect species into environment to cause a specific interaction with another member of the same species

Allomones Kairomones Synomones Favorable to Producer Favorable to Receiver Favorable to The response of the receiver is The response of the both Producer adaptively favourable to emitter, but receiver is adaptively & Receiver not the receiver. Allomones are favourable to receiver, The response of mostly defensive chemicals, but not the emitter. receiver is producing negative responses and Kairomones are adaptively reducing chances of contact and advantageous to an favourable to utilization. They include repellents, insect, such as both receiver & oviposition and feeding detterents, promoting host finding, emitter and toxicants. Kairomones are ovip osition, and feeding. advantageous to an insect, such as Feeding attractans, promoting host finding, oviposition, feeding arrestants, and feeding. (Feeding deterrents, oviposition attractants, oviposition deterrents, repellents, feeding stimulant, flight toxicants ) arrestant.

REPELLENTS & DETERRENTS (Allomones): • Repellents are either synthetic chemical or plant-based compounds that cause insects to orient their movements away from source . These materials which ward-off insect attack either on account of disagreeable odour or taste. • Allied chemicals that do not cause movement away but do prevent feeding or oviposition by insects are called feeding and oviposition deterrents , respectively. • Both repellants and deterrents are used for the plant protection, either directly or indirectly (in breeding programs). • An insect repellent is a substance applied to skin, clothing, or other surfaces which discourages insects from landing or climbing on that surface. • There is also insect repellent products available based on sound production , particularly ultrasound (inaudibly high frequency sounds).

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Repellents may be Physical and Chemical:

Repellents

Phyical repellents Chemical repellents

Heat Botanical

Light Synthetic

Colour

Sound

Plant characters

Physical repellents: • Heat, Light, Sound and Plant characters may cause insect to repell from food sources. UV light repells some insects. • Hairiness of plant species repells ahpids and leaf hoppers . • Inaudibly high frequency sounds repells insects. • Yellow colour repells moths. • Heat repells mosquitoes, and many other insects. Chemical repellants: • The chemicals (either plant based or synthetic) which elicit the repellency responces among the insects. These are usually volatile chemicals that express their activity in vapor phase. A strong repellant can induce effect from long distances (few centimeters), causing them to fly or crawl away, and weak repellants may allow the insects to alight or touch the surface before being repelled. Insect repellents help prevent and control the outbreak of insect-borne diseases such as malaria, Lyme disease, Dengue fever, bubonic plague, and West Nile fever. Pest animals commonly serving as vectors for disease include the insect’s flea, fly, and mosquito; and the arachnid tick. • Synthetic chemicals including some pesticides such as synthetic pyrethroids (permethrin) also can cause some sort of deterrent or irritant behavior in insects. Besides in plant protection, they are widely used for personal protection against mosquitoes and other haematophagous insects. • Common insect repellants (botanical and synthetic) include, DEET (N,N-diethyl-m- toluamide) ( mosquito repellent ), carboxide, dibutyl phthalate, hexamide, essential oil of lemon ( lemon oil ), Icaridin, citronella oil, catnip oil, eucalyptus oil, lavender oil (for mosquitoes) , Permethrin (mosquito repellent), Neem Oil (for most insects species) , Bordeaux mixture (repellent for some beetles) , Pinetar oil (for screw worm flies), Napthalene etc. Synthetic repellants are more effective than natural repellants. Essential oil repellants are short lived. Deterrents: Feeding deterrents or Anti-feedants:

• These substances prevent feeding by an insect or animal on treated material without necessarily killing or repelling it, inhibiting the taste receptors of mouth region . 179

• Due to this, insects may starve to death. • These are also known as phagodeterrents. • Neem extracts for locusts , and other insects. • Calyx extract of Hibiscus syriacus (alternate host of cotton boll weevil Anthonomus grandis ) is a feeding and ovipositing deterrent for boll weevil. • Sinigrin from cruciferae plants is a feeding deterrent for chewing larvae. • Thiocarbamates and Aprocarb against bollweevil. • Cantharidin (terpenoid from haemolymph of blister beetle) is a feeding deterrent to insects. Advantages of feeding deterrents: • Do not affect non-target organisms. • Effecting feeding by insects on plants. • Environmental friendly. Limitations of feeding deterrents: • Effective only against surface feeders not against internal feeders. • Good coverage is required for best use • Further new crop growth will not be protected. Oviposition deterrents: • MomordicinV (triterpene)-phytochemical from bitter melon shown to have oviposition deterrency against leafminer Liriomyza trifolii. • Ethanolic extracts of Pongamia pinnata, Datura stramonium leaves shows oviposition deterrency against mosquitoes, Aedes and Culex spp. • Extracts of neem Azadirachta indica and custard apple Annona squamosa proved to be oviposion deterrents against Corcyra Cephalonica (rice moth) and best recommended for storage of rice.

ATTRACTANTS (Kairomones) (favourable to receiver) • Attractants may be physical or chemical • Chemical substances which elicit the oriented movements by insects towards their source are called chemical attractants. • The insects may be attracted to odours, emanating from foods ( food attractants ) or from opposite sex ( sex pheromones ) or from prey or from site of oviposition ( semio chemicals ). • Molasses, Chopped oranges, chopped bananas attractants for moths • Methyl eugenol attractant for fruit flies

Attractants

Physical Chemical

Light Inter-specific

Colour Food attractants

Oviposition attractants

Intra-specific

Sex Pheromones (sex attractants) Alarm pheromones

Trial pheromones Aggregation pheromones 180

Physical attractants (Visual attractants / lures): • That light attracts many insects is common knowledge, but making use of light and its component colors in visual lures requires considerably more detailed understanding. Visual lures used in insect management fall into three general categories: (1) lights (incandescent, fluorescent, and ultraviolet) that attract insects from dark or dimly lit surroundings; (2) colored objects that are attractive because of their specific reflectance; and shapes or silhouettes that stand out against a contrasting background. • A great number of insect species are attracted to light of various wavelengths. Although different species respond uniquely to specific portions of the visible and non-visible spectrum (as perceived by humans), most traps or other devices that rely on light to attract insects use fluorescent bulbs or bulbs that emit ultraviolet wavelengths (black lights). Hundreds of species of moths, beetles, flies, and other insects, most of which are not pests, are attracted to artificial light. They may fly to lights throughout the night or only during certain hours. Key pests that are attracted to light include the European corn borer, codling moth, cabbage looper, many cutworms and armyworms, diamondback moth, sod webworm moths, peach twig borer, several leaf roller moths, potato leafhopper, bark beetles, carpet beetles, adults of root grubs, house fly, stable fly, and several mosquitoes. Lights and light traps are used with varying degrees of success in monitoring populations and in mass trapping. Light traps provide useful information about the timing, relative abundance, or species composition of flights of European corn borer, white grubs, sod webworms, and a few other pests. • Pest-O-Flash, product of PCI, electronic flying insect control system which attracts, kills and collects flies and other insects, in which UV tube is used for attracting flies. • Specific colors are attractive to some day-flying insects. For example, yellow objects attract many insects and are often used in traps designed to capture winged aphids and adult whiteflies . Red spheres and yellow cards attract apple maggot flies . Like other attractants, colored objects can be used in traps for monitoring or mass trapping. Yellow plastic tubs filled with water, for example, are used to monitor the flights of aphids in crops where these insects are important vectors of plant viruses. Aphids attracted to the yellow tub land on the water and are unable to escape. Yellow sticky- coated cards or plastic cups are widely used in mass trapping programs to help control whiteflies in greenhouses. Although recommended trap densities in greenhouses are based on studies involving only a few crops, recommendations of 1 trap per 5 square yards or 1 trap every 3 to 4 feet along benches are common. Yellow sticky traps capture adult whiteflies, not wingless nymphs. A chemical attractant is incorporated in the adhesive applied to commercially available yellow cards. Chemical attractants (food attractants, oviposition attractants, sex attractants) • Chemicals that act as attractants or carry other messages across distances are volatile (quick to evaporate) compounds . • When released into the air, they can be detected by certain insects (those receptive to a specific compound) a few inches to hundreds of yards away. Chemicals that carry messages over considerable distances are most often used in pest management. • Although terms such as pheromone and kairomones help describe the functions of message-carrying chemicals, these words often oversimplify the complexity of chemical communication. A single chemical signal may act as both a pheromone and a

kairomone; for example, the compounds emitted by a bark beetle colonizing a host tree attract other bark beetles (functioning as an aggregation pheromone), but the same 181

compounds also attract certain predators and parasites that attack these bark beetles (functioning as a feeding attractant or kairomone). Pheromones: • Pheromones (Gk. phereum , to carry; horman , to excite or stimulate) are the chemicals released by one member of an insect species into environment to cause a specific interaction with another member of the same species. • Pheromones may be further classified on the basis of the interaction mediated and upon the type of response elicited from receiving insect, such as alarm, trail, aggregation or sex pheromone . • Out of all above types of pheromones, sex pheromones are most important and best studied for the use in pest management programmes. It is the sex pheromones of insects that are of particular interest to agricultural integrated pest management (IPM) practitioners. • Sex pheromones are the chemicals released by one sex (by females, except in cotton boll weevil Anthomona grandis ) cause a sequence of responses in the receiving individual of the opposite sex, leading to mating. • Butenandt A and Carlson (1959) coined the term pheromone, and they first reported the isolation and identification of sex pheromone from silkworm . • Sex pheromones are produced by females, and males respond to female produced sex pheromones, except in cotton boll weevil, Anthomonas grandis in which males produce sex pheromones. • A range of behaviors and biological processes are influenced by pheromones, but pest management programs most often use compounds that attract a mate (sex pheromones) or call others to a suitable food or nesting site (aggregation pheromones). Other pheromones regulate caste or reproductive development in social insects (honey bees and termites for example), signal alarm (in honey bees, ants, and aphids), mark trails (ants), and serve other functions. • Practical use of sex pheromones and also feeding attractants for pest management usually requires that specific active chemicals be isolated, identified, and produced synthetically. The synthetic attractants-usually copies of sex or aggregation pheromones or feeding attractants-are used in one of four ways: (1) as a lure in traps used to monitor pest populations ; (2) as a lure in traps designed to "trap out" a pest population ; (3) as a broadcast signal intended to disrupt insect mating ; or (4) as an attractant in a bait containing an insecticide . Attractant baited-traps for monitoring pest populations: • The principle use of insect sex pheromones is to attract insects to traps for detection and determination of temporal distribution. • In most instances, it is the males who are responders to female-produced sex pheromones. • Trap baits, therefore, are designed to closely reproduce the ratio of chemical components and emission rate of calling females. • For use in monitoring, chemical attractants usually are impregnated or encased in a rubber or plastic lure that slowly releases the active component(s) over a period of several days or weeks. Traps containing these lures are constructed of paper, plastic, or other materials. Most traps use an adhesive-coated surface or a funnel-shaped entrance

to capture the target insect. • Usually 4 pheromone traps/acre are installed for the purpose .

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Attractant-baited traps are used in monitoring programs for at least three purposes: (1) to detect the presence of an exotic pest (an immigrant pest not previously known to inhabit a state or region); The use of traps to detect exotic pests has been demonstrated in widely publicized efforts to detect and eradicate pests such as the gypsy moth and the Mediterranean fruit fly, Ceratitis capitata whenever infestations are detected in new areas. (2) to estimate the relative density of a pest population at a given site; and (3) to indicate the first emergence or peak flight activity of a pest species in a given area, often to time an insecticide application or to signal the need for additional scouting. Attractant baited traps to trap-out pest populations (mass trapping): • Because pheromone traps are so effective for catching certain insects, numerous traps placed throughout a pest's environment can sometimes remove enough insects to substantially reduce the local population and limit the damage it causes. • Efforts to "trap out" insect pests (a process also termed removal trapping or mass trapping) have utilized species-specific aggregation pheromones that attract both male and female beetles and species-specific sex pheromones that attract male moths. When aggregation pheromones are used to attract adult beetles of both sexes, traps may reduce the feeding damage caused by the adult insects and reduce reproduction by capturing adults before they lay eggs. When sex pheromones are used to capture moths, success depends upon capturing males before mating occurs. Although mass trapping programs using chemical attractants have targeted such important pests as bark beetles, codling moth, apple maggot, Japanese beetle, and Indian meal moth, field-scale successes have been limited. Using attractant to disrupt mating: • To disrupt insect mating, species-specific sex pheromone is broadcasted throughout an area. • In an environment permeated with artificially applied sex pheromone molecules, male insects that rely on pheromones to locate females are unable to do so . They either follow an artificial signal to a frustrating destination or their sensory receptors become overloaded by constant exposure to pheromone molecules, leaving the insect temporarily unable to detect additional pheromone messages. Using attractants as poison bait: • Combining insect attractants with poisons (insecticides) is a practice that has been used in pest management for many years. • In the early 1900s, for example, poisoned bran baits were used for grasshopper control ; hoppers that were attracted to the treated bran and fed on it were killed by an insecticide that could not be applied safely, economically, or effectively in any other manner. • Insecticidal baits are used currently in the control of several pests including the house fly, fruit flies, slugs, certain ants, cockroaches, and yellow jackets. • Similarly attractants like methyl eugenol, cuelure and jaggery in poison bait preparation play role in attracting the pests like fruit flies . • Poison bait for many lepidopterans like cutworm, hairy caterpillars consists of poison, carrier and an attractant like jaggery which has sweet smell (5kg of rice bran+500g jaggery+500g carbaryl/5ml of methomyl will be made into small balls and spread/broadcasted in fields for the control).

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The following are the attractants (kairomones/pheromones) isolated / synthesized for the pest management purposes.

Chemical name Action Isolated from Brevicomin Coleopteran attractant Black turpentine beetle Dendroctonus brevicomis Dominacalure Coleopteran attractant Lesser grain borer Rhyzopertha dominica Grandlure Coleopteran attractant, Cotton boll weevil Anthonomus grandis Mating disrupter Trimedlure Dipteran attractant Mediterranean fruit fly Ceratitis capitata Ceralure Dipteran attractant Mediterranean fruit fly Ceratitis capitata Medlure Dipteran attractant Mediterranean fruit fly Ceratitis capitata Cuelure Dipteran attractant Oriental fruit fly Bactrocera cucurbitae Disparlure Lepidopteran attractant, Gypsy moth Lymantria dispar mating disrupter Gossyplure Straight Chain Pink boll worm Pectinophora gossypiella Lepidopteran Pheromone, Mating Disrupter Litlure Straight Chain Tobacco cut worm Spodoptera litura Lepidopteran Pheromone Looplure Straight Chain cabbage looper Trichoplusia ni Lepidopteran Pheromone Eugenol, methyl Unclassified insect Synthetic chemicals for attracting fruit flies eugenol, Siglure attractant

• Methyl eugenol is sex attractant for fruit flies . Methyl eugenol coated plywood pieces will be kept in mango orchard at the fruit ripening stage to attract fruit flies. • Insect attractants and traps are useful tools for monitoring insect populations to determine the need for control or the timing of control practices . • In some instances, attractants and traps also can be used to control insect populations directly by mass trapping or mating disruption . • Using attractants and traps to monitor and control insect populations can improve the effectiveness of insecticide applications and sometimes reduce the use of broad- spectrum, more toxic compounds. • The attractants are environmental friendly , not affecting the non-target organisms , and also can be used in mass trapping programmes, but one cannot solely rely on these for effective control of the pest.

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Gamma irradiation in Insect pest control: • Gamma irradiation: Mangoes for export are treated with gamma rays (irradiation treatment) for the control of mango nut weevil ( Sternochetus mangiferae ). It is recommended as quarantine treatnment for mango exports to USA. • X-rays and Gamma rays used for making insect sterile .

Genetic modifications (Genetic control or Genetic incompatibility): • A method using recombinant DNA technology to create genetically modified insects called RIDL (Release of Insects carrying a Dominant Lethal) is under development by a company called Oxitec. • The method works by introducing a repressible " Dominant Lethal" gene into the insects. This gene kills the insects but it can be repressed by an external additive, which allows the insects to be reared in manufacturing facilities. This external additive is commonly administered orally, and so can be an additive to the insect food. The insects can also be given genetic markers, such as fluorescence, that make monitoring the progress of eradication easier. • There are potentially several types of RIDL, but the more advanced forms have a female-specific dominant lethal gene . This avoids the need for a separate sex separation step, as the repressor can be withdrawn from the final stage of rearing, leaving only males. These males are then released in large numbers into the affected region. The released males are not sterile, but any female offspring their mates produce will have the dominant lethal gene expressed, and so will die. The number of females in the wild population will therefore decline, causing the overall population to decline. • Using RIDL means that the males will not have to be sterilized by radiation before release, making the males healthier when they need to compete with the wild males for mates. • Progress towards applying this technique to mosquitos has been made by researchers at Imperial College, London who created the world's first transgenic malaria mosquito.

Sterile Insect Technique (SIT): • Sterile insect technique is a method of biological control, whereby millions of sterile insects are released. The released insects are normally males as it is the female that causes the damage, usually by laying eggs in the crop, or, in the case of mosquitoes, taking a blood meal from humans. The sterile males compete with the wild males for female insects. If a female mates with a sterile male then it will have no offspring, thus reducing the next generation's population. Repeated release of insects can eventually wipe out a population, though it is often more useful to consider controlling the population rather than eradicating it. The technique has successfully been used to eradicate the Screw-worm fly (Cochliomyia hominivorax ) in areas of North America. There have also been many successes in controlling species of fruit flies, most particularly the Medfly (Ceratitis capitata ), and the Mexican fruit fly ( Anastrepha ludens ). • The technique was pioneered in the 1950s by American entomologists Dr. Raymond C Bushland and Dr. Edward F Knipling. For their achievement, they jointly received the 1992 World Food Prize. • Insects are mostly sterilized with radiation, which might weaken the newly sterilized

insects, if doses are not correctly applied, making them less able to compete with wild males. However, other sterilization techniques (using chemicals) are under development which would not affect the insects' ability to mate. 185

• During the 1960s and 1970s, SIT was used to control the screwworm population in the United States. The 1980s saw Mexico and Belize eliminate their screwworm problems through the use of SIT, and eradication programs have progressed through all of Central America, with a biological barrier having been established in Panama to prevent reinfestation from the south. In 1991, Knipling and Bushland's technique halted a serious outbreak in northern Africa. Similar programs against the Mediterranian fruit fly in Mexico and California use the same principles. In addition, the technique was used to eradicate the melon fly from Okinawa and has been used in the fight against the tsetse fly in Africa . • The technique has been able to suppress insects threatening livestock, fruit, vegetable, and fiber crops. The technique has also been lauded for its many environmentally sound attributes: it uses no chemicals, leaves no residues, and has no effect on non- target species. This technique uses radiation for inducing sterility. • Proven effective in controlling outbreaks of a wide range of insect pests throughout the world, the technique has been a boon in protecting the agricultural products to feed the world’s human population. Both Bushland and Knipling received worldwide recognition for their leadership and scientific achievements, including the World Food Prize. . Their research and the resulting Sterile Insect Technique were hailed by former U.S. Secretary of Agriculture Orville Freeman as " the greatest entomological achievement of (the 20th) century ." Male sterility by irradiation with Gamma rays: • The males of the insect pests are sterilized by subjecting them to lower doses of Gamma radiation, and then released into an area infested with normal populations of the insect pest. • If the radiation dose is high, it results in moratality. • The sterilized males effectively compete with nautal males in mating with natural females, and the off-spring or the progeny resulting from sterile male mating, will be sterile and hence in course of time, the natural populations will be reduced, and the pest is effectively controlled. • This theory of male sterile technique was conceived by Knipling as early as 1937, and was published in 1955. Major drawbacks: • As for insecticide treatment, repeated treatment is sometimes required to suppress the population before the use of sterile insects. • Sex separation could be difficult for some species, though this can be easily performed on medfly and screwworm , for example. • Radiation treatment in some case, over doses, affects the health of males, so sterilized insects in such cases are at a disadvantage when competing for females. • The technique is species specific, for instance: there are 22 species of tsetse fly in Africa, and the technique must be implemented separately for each. • Standard operating procedures of mass rearing and irradiation, do not leave room for mistakes. Since the fifties, when SIT was first used as a means for pest control, several failures have occurred in different places around the world where non-sterilized artificial produced insects were released before the problem was spotted. • Application to large areas should be long lasting, otherwise migration of wild insects from outside the control area could repopulate. • The major drawback to this technique is in the poor countries where it is often prohibitive the cost of producing such a large number of sterile insects.

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Chemosterilants: • This is another way of rendering insects sterile, by using chemical substances. • Chemicals that induce sterility are called chemosterilants. A number of chemicals (chemosterilants) show promise of producing sexual sterility in insects without some of the practical limitations of radiation. • Both males and females may be sterilized in this case • They are applied as contact and stomach poisons • Sterilization of males can in certain circumstances be more efficient than killing as a method for control of insects and perhaps other pests. • The sterilized insects mate normally but do not produce viable off-spring • Eggs are not laid, if laid, do not hatch, if they hatch, larvae may not pupate, if pupate, may not emerge into adults • Alkylating agents: The most important compounds are alkylating agents. These have little immediate pharmacological action, but are notable for their selective action against haematopoietic and some other proliferating tissues. A number of alkylating agents have been shown to be mutagens in insects , bacteria, fungi, and higher plants; carcinogens in mammals ; and teratogens in insects, birds, and mammals . Some produce sexual sterility, possibly in mammals as well as in insects, at doses too low to produce the other effects . Some have an established reputation as drugs for palliative treatment of leukaemia and other neoplasms. Apholate, tepa, metapa, thiotepa –induce permanent sterility in both males and females Mexican fruit fly pupa dipped in 5% Tepa solution result in permanent sterility, and these sterile males are released along the Mexican border. In Florida, weekly application of 0.5% Tepa bait against houseflies was successfully released. In Loussiana State, boll weevil males dipped in 2% Apholate solution released in cotton, suppressed the pest. Pupae of male Culex pipens exposed to 0.6% Thiotepa for 3 hours result permanent sterility. • Antimetabolites: Amethopterins-females house flies are more susceptible than males • Other miscellaneous groups: Hempa and Hemel-male house fly sterilants

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Lecture: 30 Rodenticides- zincphosphide, aluminum phosphide, bromodilone; Acaricides- sulphur, dicofol, tetradiform; fumigants- aluminum phosphide.

RODENTICIDES: • Rodenticides (Rat Killers) chemicals/substances intended to kill rodents (rats, mice and other rodent pests). • Rodents are difficult to kill with poisons because their feeding habits reflect their place as scavengers. They will eat a small bit of something and wait, and if they don't get sick, they continue. An effective rodenticide must be tasteless and odorless in lethal concentrations, and have a delayed effect . • These are the agents to kill mammals, and hence are extremely toxic to humans. To be used under strict supervision of expert. Warfarin and other anti-coagulant chemicals (Coumarins) were initially developed to overcome this problem by creating compounds that were highly toxic to rodents, particularly after repeated exposures, but much leass toxic to humans. New super-warfarins (eg: Bromadiolone) are available and toxic at much lower doses than conventional warfarins. • Since the rodents usually share the environment with humans, accidental exposure is an integral part of the placement of baits for the rodents.

Rodenticides

Inorganic Organic (Metal Phosphides) Zinc phosphide Thallium sulfate Yellow phosphorous

Botanical

Convulsants Eg: Strychnine

Miscellaneous Eg: Red Squill

Synthetic

Coumarins / Anti -coagulants Bromadiolone Warfarins

Convulsants Crimidine Fluroacetamide

Miscellaneous Cholecalciferol

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Metal Phosphides: (Inorganic rodenticides) • Metal phosphides have been used as a means of killing rodents and are considered single-dose fast acting rodenticides (death occurs commonly within 1-3 days after single bait ingestion). • Bait consisting of food and a phosphide (usually zinc phosphide ) is left where the rodents can eat it. The acid in the digestive system of the rodent reacts with the phosphide to generate the toxic phosphine gas. • This method used in places where rodents are resistant to some of the anticoagulants, particularly for control of house and field mice; • Zinc phosphide baits are also cheaper than most second-generation anticoagulants (super-warfarins). • Inversely, the individual rodents, that survived anticoagulant bait poisoning (rest population) can be eradicated by pre-baiting them with nontoxic bait for a week or two (this is important to overcome bait shyness , and to get rodents used to feeding in specific areas by specific food, especially in eradicating rats) and subsequently applying poisoned bait of the same sort as used for pre-baiting until all consumption of the bait ceases (usually within 2-4 days). These methods of alternating rodenticides with different modes of action gives actual or almost 100% eradications of the rodent population in the area, if the acceptance/palatability of baits are good (i.e., rodents feed on it readily). • Zinc phosphide is typically added to rodent baits in amount of around 0.75-2%. • The baits have strong, pungent garlic-like odor characteristic for phosphine liberated by hydrolysis . The odor attracts (or, at least, does not repulse) rodents, but has repulsive effect on other mammals. Birds (notably wild turkeys) are not sensitive to the smell, and will feed on the bait, and thus become collateral damage. • The tablets or pellets (usually aluminium , calcium or magnesium phosphide for fumigation/gassing) may also contain other chemicals which evolve ammonia which helps to reduce the potential for spontaneous ignition or explosion of the phosphine gas. • Phosphides do not accumulate in the tissues of poisoned animals; therefore the risk of secondary poisoning is low. • Before the advent of anticoagulants, phosphides were the favored kind of rat poison. During the World War II, they came in use in United States because of shortage of strychnine due to the Japanese occupation of the territories where strychnine- producing plants are grown ( Strychnos nux-vomica , in south-east Asia). • Phosphides are rather fast acting rat poisons , resulting in the rats dying usually in open areas instead of in the affected buildings. Phosphides used as rodenticides are : • Aluminium phosphide (fumigant only) (Celphos, Quick-phos, Alphos tablets) (available in 3 g tablets, widely used in India as grain preservative for storage grain insect pests. Each 3 g tablet liberates 1 g phosphine gas) • Calcium phosphide (fumigant only) • Magnesium phosphide (fumigant only) • Zinc phosphide (in baits): Zinc phosphide has long been in use for the control of rodents. It is a dark grey powder and smells like garlic. It decomposes slowly in the presence of moisture. It is used as a 2% bait for the control of field rats. Ingested zinc

phosphide reacts with the hydrochloric acid present in the stomach and releases the phosphine gas.

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Botanical origin Rodenticides: • Strychnine . The most common source is from the seeds of Strychnos nux vomica . It is one of the bitterest substances known. It causes muscular convulsions and causes death due to asphyxia and sheer exhaustion. • Red squill , a scillirocide (glycoside), a rodenticide derived from the bulbs of a lilylike subtropical plant, is slower-acting. Scillirocide has an emetic-property . So, if rodents ingest a product with red squill, because the rodents are incapable of vomiting, they develop glycoside intoxication and pulmonary adema, and finally leading to death. Less toxic to animals other than rodents because it is removed from the stomach by vomiting-a reflex that is absent in rodents. Synthetic Coumarins: Warfarins and Bromadiolone . • Coumarins are sweet smelling/pleasantly fragrant chemicals either botanical origin or synthetic with anti-coagulant activity . • Coumarins depress the hepatic synthesis of Vitamin K dependant blood-clotting factor II. The anti-prothrombin effect is best known. They also increase permeability of capillaries throughout the body, predisposing the animal to widespread internal hemorrhage . This generally occurs after several days of warfarin poisoning / ingestion. • These substances hill the rodent by preventing normal blood clotting and causing internal hemorrhage . • Slow acting rodenticides , require pre-baiting . • Warfarin : A first-generation coumarin rodenticide. An anti-coagulant acting, effectively blocking Vitamin K cycle, causing Hemophilia. Banned for use, as is highly toxic to humans. It has shorter half-lives, and hence requires high doses / concentrations for consecutive days (multiple dose rodenticides). (Warfarin is a synthetic derivative of dicoumarol, anticoagulant originally discovered in spoiled sweet clover-based animal feeds. Dicoumarol, in turn, is derived from coumarin, a sweet-smelling but coagulation-inactive chemical found naturally in sweet clover and many other plants. The name warfarin stems from its discovery at the University of Wisconsin, incorporating the acronym for the organization which funded the key research ( WARF , for Wisconsin Alumni Research Foundation ) and the ending -arin, indicating its link with coumarin). • Bromadiolone: A second-generation coumarin rodenticide with anti-coagulant activity (vitamin K antagonist). They are very toxic to mammals than first-generation coumarins, but due to its usage at very doses @ 0.001-0.005% in baits (multiple dose rodenticides), they can be used safely. These are also called as super-warfarins since they are lethal at very low doses. Others: • Crimidine, synthetic chlorinated pirimidine compound causes violent convulsions.

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ACARICIDES: • Acaricides are pesticides that kill members of the Acarina group, which includes ticks and mites . They are also called as miticides (kills mites), and ixodicides (kills ticks) . • Acaricides are used both in medicine and agriculture , although the desired selective toxicity differs between the two fields.

Macrocyclic lactones Abamectin , Ivermectin Oragnochlorines DDT, Dicofol Carbamates Carbaryl, Carbofuron, Propoxur, Aldicarb Formamidine Chlordemiform, Amitraz Organophosphates Monocrotofos, Chlorpyrifos, Dimethoate, Ethion, formothion, parathion, phorate, Phosalone, triazophos Phenyl Pyrazole Fipronil Pyrethoids Cypermethrin, fluvalinate Unclassified Sulfur, propargite, tetradifon, Spiromesifen, bifenazite

Sulfur: • Sulfur is a non-systemic contact and protectant fungicide with secondary acaricidal activity. • It is usually formulated as a dust (90%D), with up to 10% inert material to prevent balling. • Dust flow can be increased by the addition of 3% tricalcium phosphate. • It is also formulated as a wettable powder (80%WP), and is recommended @ 2.0-2.5 kg formulation/ha or 2g/lit as per requirement. • Thiovit 80%WP (Syngenta), Sulfex 80%WP (Excel), Dicofol: • Persistant organochlorine acaricide od moderate mammalian toxicity • Metabolic product of DDT • Kelthane 18.5%EC and Kelthane 50WP (Dow Agro) is available in market. • Non-systemic • Recommended @ 0.5-2.0 kg ai/ha • Broad-spectrum miticide Propargite: (Omite 30%WS-Chemtura chemicals) • Omite® miticide has been a valuable part of tree and vine crop production for over 30 years. While a few mites won't create economic damage, they can be an indication of things to come. Mite populations can explode in a short time, and if millions of mites are left to feed untreated, the destruction can approach catastrophic proportions, result in reduced yields at harvest. • When applied according to label directions, it keeps mite populations below damaging levels. Omite controls a broad spectrum of mite species while being easy on beneficial insects and mite predators . • Omite miticide fits IPM programs and controls mites resistant to other miticides. • Omite gives long residual activity with a combination of chemical and natural control and is more economical to use than most other miticide products. • It is compatible with many other pesticides

• Omite is not systemic in action ; therefore, coverage of both upper and lower leaf surfaces and fruit is necessary for effective control.

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Formamidines: (Chlordimeform, Amitraz) • A new group of acaricidal insecticidal compounds , used as plant sprays and topically on animals. • Examples: Chlordimeform (CDM), Amitraz (Mitaban 19%EC, Preventic 19%EC) • Their biological activity and uses are defined by their toxicity to spider mites, ticks, and certain insects and they are particularly effective against juvenile and resistant forms of these organisms. • Mode of action: Although many reported underlying biochemical mechanism, including inhibition of monoamine oxidase activity, uncoupling of respiration and blockade of neuromuscular transmission . Recently, interaction with octopamine receptors in the central nervous system is also reported. • Amitraz: on animals it is used to control ticks, mites, lice and other animal pests . Very popular veterinary drug. Ketoenols: (Spiromesifen -Oberon 240SC -Bayer ) • Very unique mode of action through inhibition of lipid bio-synthesis and acetyl- CoA- carboxylase. • Non-systemic acaricide with translaminar action. • Stomach poison with some contact action. • Effects egg and immature stages of mites. • Registered for use in India during 2009.

FUMIGANTS: • Fumigants are insecticidal gases, actually contact poisons applied in gaseous form . • They are released in the vapor state (as gases) • Enter the insect's body through its tracheal system. The gases enter into system through breathing pores and kills the system either hampering nervous system or respiratory system . • Fumigants are most effective when they are used in an enclosed area such as a greenhouse, a warehouse, or a grain bin. • Insects that are hard to reach by sprays are killed when they breathe or are exposed to the gas. Fumigants are used by professional exterminators to kill the cockroaches, bedbugs and to kill insect pests in grain bins/storage. • The soil may be fumigated to destroy grubs that attack roots. • Fumigants are highly toxic , and hence fumigation is a hazardous operation. • Commonly used fumigants are Aluminium phosphide (marketed as celphos, quick-phos, alphos, phostoxin tablets of 3g each used against storage pests @ 4 tablets/ton. Each tablet produce 1g phosphine gas; ½ tablet is recommended for red palm weevil in coconut, one tablet of 3g is recommended for 1 metric tonne of grain in storage). 3 Carbon disulphide (CS 2) @ 8-20lbs/1000ft EDB (Ethylene Dibromide) @ 1lb/1000ft 3 SO 2 fumes by burning sulphur CCl 4 (Carbon tetra chloride) Napthalene ED (Ethylene dibormide) EDCT (Ethylene dibromide + carbon tetra chloride)

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Lecture: 30 Application techniques of spray fluids- high volume, low volume and ultra low volume sprays; phytotoxic effects of pesticides-advantages and limitations of chemical control-safe use of insecticides.

• Chemicals are widely used for controlling disease, insects and weeds in the crops. They are able to save a crop from pest attack only when applied in time. They need to be applied on plants and soil in the form of spray, dust or mist. The chemicals are costly. Therefore, equipment for uniform and effective application is essential. • Dusters and sprayers are generally used for applying chemicals. • Dusting, the simpler method of applying chemical, is best suited to portable machinery and it usually requires simple equipment. But it is less efficient than spraying, because of the low retention of the dust. • The Sprayer is one which atomises the spray fluid (which may be a suspension, an emulsion or a solution) into a small droplets and eject it with little force for distributing it properly . It also regulates the amount of pesticide to avoid excessive application that might prove wasteful or harmful. • Spraying is employed for a variety of purposes such as application of: i. Herbicides in order to reduce competition from weeds, ii. Protective fungicides to minimize the effects of fungal diseases, iii. Insecticides to control various kinds of insects pests, iv. Micro-nutrients such as manganese or boron, • The main function of a sprayer is to break the liquid into droplets of effective size and distribute them uniformly over the surface or space to be protected . • Another function is to regulate the amount of insecticide to avoid excessive application that might prove harmful or wasteful . • A sprayer that delivers droplets large enough to wet the surface readily should be used for proper application. Extremely fine droplets of less than 100 micron size tend to be diverted by air currents and get wasted. • Crops should, as far as possible, be treated in regular swaths. By use of a boom, uniform application can be obtained with constant output of the machine and uniform forward travel. • High volume spraying is usually effective and reliable but is expensive. Low volume spraying to some extent overcomes the failings of each of the above two methods while retaining the good points of both.

Classification of Spraying Technologies: Spraying techniques are classified as high volume (HV), low volume (LV) and ultra low volume (ULV), according to the total volume of liquid applied per unit of ground area. High volume spray (HV): thoroughly wet treated foliage until spray runoff, often applying 500L-1000L of spray solution per hectare (200L-400L per acre) in case of field crops, while in case of orchards, 1500-2000L/ha is required, using equipments such as inexpensive knapsack sprayer or compressed air sprayer or hydraulic sprayers for treating large areas. High volume sprayers usually produce a wide range of different size of droplets (>100 µm in diameter, usually 300-400 µm). Because large droplets settle quickly on plants, there is less possibility of drift in air, reducing the likelihood of pesticide

movement off-site. However, large drolets are undesirable because they often, (a) runoff of the spray target, (b) tend to pool in cupped surfaces, and on lower edges of plants where the higher dose risks phytotoxicity, (c) often do not provide good coverage on the 193

underside of the leaves, (d) require a larger volume of spray than smaller droplets to cover the surfaces, resulting in relatively high amount of active ingradient requirement per unit area. The coverage would be 1ha/day. Low volume (LV) applications produce very small droplets (70-150µm in diameter). These smaller droplets have much larger surface area per unit volume than larger droplets. Low volume sprayers usually apply <120L of spray fluid per acre, much less than high volume sprayers. However, low volume sprayers require higher rate of active ingradient (8-25 times) in the spray solution than high volume sprays, and hence they are also called as concentration sprays. Low volume spray is often limited to newer insecticides, because only new molecules lables provide information on directions for low volume applications. Low volume sprayers have many advantages compared to high volume sprayers. The smaller diameter droplets (70-150 µm) from LV sprayers provide better coverage and are more effective than larger droplets when treating plants and foliage eating insects. Because the smaller droplets increase the risk of drift, measures to be taken for preventing off-site movement of insecticide, including adding the appropriate adjuvants to the spray mix, using good application techniques such as properly aiming sprays, employing proper nozzles, lowering spray pressure, and not spraying during adverse conditions such as high temperatures and wind. The coverage would be 3-5ha/day. Ultra low volume spray (ULV) : The insecticide applied undiluted, in small quantities, usually @ 0.5-6L/ha with heli sprayer or ULV sprayer of centrifugal sprayer or by mist blowers fitted with replicator nozzle or aircraft with special nozzles. They are also known as air-blast sprayers, air-blowers, mist-blowers etc. The size of the droplet varies from 20- 100 µm, and the coverage is 18h/day. In this type of spray, air is the carrier of the toxicant but not the water like in other cases. The spray will not result in run-off of the toxicant. Advantages of LV sprays: More area in Less time Less cost (in transport of water, and less labour) Timely control of pest is possible due to speedy spray application No hazards in handling, as the original container can be diretly attached Weight of spray applicane is very less Effective against epidemics, as the larger area can be sprayed in short time More effective since the concentration is high Disadvantages of LV sprays: Risk of loss of chemical due to evaporation of water Risk of loss of chemical due to drift Specialized formulations are required

Specifications High Volume Low Volume Ultra-Low Volume Spray volume/ha 500-1000L <120L 0.5-6.0L Size of droplet ( µm) >100 70-150 20-100 Coverage (ha/day) 1 3-5 18 Type of sprayer Knapsack sprayer LV sprayer ULV sprayer Dilution of insecticide Highly diluted Moderately diluted No dilution (8-25 times concentrated than HV) Carrier Water Water Air

Risk of Drift Very less Moderate High Risk of Runoff High Nil Nil

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• Initially high volume spraying technique was used for pesticide application but with the advent of new pesticides the trend is to use least amount of carrier or diluent's liquid. • In spraying, the optimum droplet size differs for different types of application. Fine droplets are required to control insect pests or diseases and bigger size droplets for application of herbicides, etc. The greater the number of fine droplets produced by the device better will be deposition on target area. The size of droplet is important as it affects drift and penetration distance of droplets towards the target. Hence a compromise is to be made to prevent drift, achieve wide coverage of plant or target area and more penetration. The optimum droplet sizes are indicated in below: Target group Droplet size (microns) Flying insects (drift) 10-15 Crawling and sucking insects (drift) 30-50 Plant surfaces (limited drift) 60-150 Soil application (no drift, as in case of herbicides) 250-500

Types of Spraying Equipment: Sprayers are classified into four categories on the basis of energy employed to atomise and eject the spray fluid as hydraulic energy sprayer, gaseous energy sprayer, centrifugal energy sprayer and, kinetic energy sprayer. • Hydraulic energy sprayer: Hydraulic Energy Sprayer is one which the spray fluid is pressurised either directly by using a positive displacement pump or by using an air pump to build the air pressure above the spray fluid in the air tight container. The pressurized fluid is then forced through the spray lance, which controls the spray quantity and pattern. • Gaseous energy sprayer: In Gaseous Energy Sprayer high velocity air stream is generated by a blower and directed through a pipe at the end of which the spray fluid will be allowed to trickle by the action of gravity through a diffuser plate. • Centrifugal energy sprayer: In the Centrifugal Energy Sprayer the spray fluid fed under low pressure at the centre of a high speed rotating device (Such as flat, concave or convex disc a wiremesh cage or bucket, a perforate sieve or cylinder or a brush) is atomised by centrifugal force as it leaves the periphery of the atomiser. The droplets are carried by the air stream generated by the blower of the sprayer or by the prevailing wind, if the sprayer is not provided with a fan. • Kinetic energy sprayer: In Kinetic Energy Sprayer the spray fluid flows by gravity to a vibrating or oscillating nozzle which produces a coarse fan shaped spray pattern. This is used for application of herbicides. Different designs of spraying equipment have been developed for different types of applications and field and crop conditions. • Manually operated hydraulic sprayers viz.Knapsack sprayers, twin knapsack sprayers, foot sprayers, hand compression sprayers; air carrier sprayers such as motorized knapsack mist blower cum duster (LV) and centrifugal rotary disc type sprayers are specially suitable for spray applications in crops. • The present trend is to apply concentrated pesticides by means of low and ultra low volume sprayers. This has been possible through the development of better formulations and special nozzles. New Controlled Droplet Application (CDA) atomizers require less than 15 l/ha of spray mixture and are easy to operate. Although new type of spray atomizers is available but the correct chemical formulations are commonly not produced. Hence their use is limited to particular crop, pest or disease. • Hand sprayer is a small capacity pneumatic sprayer with tank capacity of 05.-3L. Commonly used for small nurseries, roses, home gardens. • Hand compression sprayers are either pressure retaining or non-pressure retaining type. The capacity of the tank can be 6L, 8L, 12L, 14L, or 16L. This is commonly used in nurseries, gardens, filed crops. • Rocker sprayer is a long lever high-pressure sprayer designed for operation with one or two lances. Useful for spraying on tall trees like coconut, areca nut, sugarcane, rubber plantations, orchards, vineyards and field crops, vegetable gardens, flower crops etc. • Foot sprayer is one of the ideal and versatile sprayers used for multipurpose spraying jobs. The principle of working is similar to the rocker sprayer. The foot sprayer is all purpose sprayers,

suitable for both small and large scale spraying on field crops, in orchards, vegetable gardens, tea and coffee plantations, rubber estates, flower crops, nurseries etc. 195

• Knapsack sprayer consists of a pump and an air chamber permanently installed in a 9 to 22.5 liters tank. The handle of the pump extending over the shoulder or under the arm of operator makes it possible to pump with one hand and spray with the other. Uniform pressure can be maintained by keeping the pump in continuous operation. Knapsack sprayers are used for spraying insecticides and pesticides on small trees, shrubs and row crops. • Power sprayer is used for developing high pressure and high discharge for covering large area. These sprayers are either operated by auxiliary engines or electric motors. Most of these sprayers are hydraulic sprayers and consist of power unit to drive the pump, pump unit which employs piston or plunger pump, piston, pressure gauges, pressure regulators, air chamber, suction pipe with strainer, delivery pipes fitted with lance, gooseneck bend and nozzles. The portable sprayers use petrol eflgine so that these can be easily taken to the spray sites. The complete assembly is mounted on the stretcher type frame or on wheel barrow for easy transportation. Sprayers are suitable for spraying in orchards, tea and coffee plantations, rubberplantations, vineyards and field crops. Tall trees up to a height of 15 meters can be sprayed with these types of sprayers. • Motorized knapsack mist blower has a small 2-stroke petrol/ kerosene engine of 35 cc to which a centrifugal fan is connected. The centrifugal fan is usually mounted vertically. The fan produces a high velocity air stream, which is diverted through a 90-degree elbow to a flexible (plastic) discharge hose, which has a divergent outlet. The spray tank that has also a compartment for fuel and engine-fan unit is mounted on a common frame, which fits to the back of operator. The tank is made of plastic. The spray liquid flows due to gravity and suction created at the tip of nozzle, thus remains in the air stream. It is used for spraying in orchards, coffee estates and tall crops. • ULV sprayers are also known as controlled droplet application (CDA) sprayers and can apply correct size of droplets. Due to very low volume application features the spray chemicals can be applied in very low dilution or no dilution at all with these sprayers. Common type of ULV sprayers are hand held and number of these units can be mounted on the boom attached to the tractor to increase the field capacity. • Fogging machine: When droplets smaller than 15mm fi ll a volume of air to such an extent that visibility is reduced, the air is termed as fog. Usually ,-thermal fogging machines are used to create fog in which pesticide dissolved in oil of suitable flash point is injected in the hot gases produced by burning the fuel. The liquid is vaporised which condenses on coming contact with air. Commly used by municipality people for fogging Malathion for mosquito control .

Phytotoxic effects of Insecticides: • Phytotoxic means harmful or lethal to plants . Phytotoxicity is the degree to which a chemical or other compound is toxic to plants. Some insecticides cause adverse effects on the plants is called phytotoxicity of the insecticide. • All types of pesticides can injure or kill plants. Herbicides are especially hazardous to plants because they are designed to kill or suppress plants. Some insecticides and fungicides can also harm plants. Phytotoxic effects caused by herbicides can be from spray droplets, soil residues or vapours contacting sensitive plants. Plants can also be harmed by herbicides which move off target in water or soil or when sensitive crops are planted in fields too soon after a herbicide treatment was applied for a previous crop. • Phytotoxic properties of pesticides are usually associated with specific formulations (wettable powder, emulsifiable concentrate, granule, etc) or specific plants rather than groups of pesticides or plants. A pesticide label may indicate whether the pesticide could be phytotoxic, and may list plants or varieties that are sensitive. • Phytotoxic effects can range from slight burning or browning of leaves to death of the plant. Sometimes the damage appears as distorted leaves, fruit, flowers or stems. Damage symptoms vary with the pesticide and the type of plant that has been affected.

• These effects on the plants are either permanent or temporary, allowing plant to recover. 196

• Some chemicals may be phytotoxic to some plants even at recommended doses. Many of the chemicals which are non-phytotoxic at recommended doses may be phytotoxic at higher doses. • Phytotoxicity is not necessarily caused by the active ingredient . Plant damage can also be caused by: the solvents in a formulation, impurities in spray water, using more pesticide than listed on the label, or poorly mixing the spray solutions. Higher concentrations of the solvents used in the formation, and their volatile properties may also be responsible for phytotoxicity of the chemical. • Hence, thorough knowledge of the phytotoxicity of the chemicals and the dosage at which they are to be used is essential for plant protection worker and to the farmer using combination of pesticides (tank mixtures of pesticides). The classical example: DDT and HCH are phytotoxic to cucurbits. • Condition of the plant at the time of treatment can affect phytotoxicity; stressed plants may be more susceptible. • Environmental conditions such the temperature, humidity, and light can influence phytotoxicity. High temperatures can speed up pesticide degradation and volatilization, but may also result in increased phytotoxicity for some products. UV light rapidly breaks down many pesticides. • Soil properties such as texture, temperature, moisture, microbial activity and pH also influence phytotoxicity. Higher pH soils are less binding and may increase photoxicity. High microbial activity can reduce phytotoxicity. Pesticide compatibility: • Applying a tank mix of pesticides, or a pesticide and a liquid fertilizer, can save time, labor, energy and equipment costs. • Pesticide combinations usually alter plant absorption and translocation as well as metabolism and toxicity at the site of action of one or more of the mixed products. Not all changes are for the better. Negative effects can occur such as reduced pest control, increased damage to non-target plants (phytotoxicity and incompatibility problems between materials. Incompatibility: chemical and physical • Two or more pesticides, or a pesticide and a fertilizer, are compatible if no adverse effects occur as a result of mixing them together. • The possible effects of mixing incompatible chemicals are many and include: 1. Reduced effectiveness of one or both compounds. 2. Precipitate in the tank, clogging screens and nozzles in the sprayer. 3. Plant phytotoxicity, stunting or reducing seed germination. 4. Excessive residues. 5. Excessive runoff. • Chemical incompatibility: The deactivation of an active ingredient often occurs with chemical incompatibility. This is most affected by temperature, tank p H and length of time that you hold a spray mixture in the tank before use. Bordeaux mixture and lime sulfur are incompatible with most chemicals except cyclodienes (endosulfan). • Physical incompatibilities usually involve the inert ingredients of a formulation. The mixture may become unstable, forming crystals, flakes, or sludge that may clog spray equipment. Incompatibility most often occurs when you mix an emulsifiable concentrate (EC) formulation with wettable powders (WP). Similarly, you should not

mix EC insecticides with fungicides or herbicides. Liquid fertilizers can also cause compatibility problems, mainly due to their strong electrochemical nature. Be sure to

read and heed all pesticide labels! 197

• Other Incompatibilities: It is necessary to time pesticide applications when the pest is at its most vulnerable stage of development. When using two or more chemicals to manage different pests, it is critical that the mixture be applied at the correct time in the life cycle of the pests. Timing is especially important when applying herbicides. If herbicides are applied to wilted or stressed plants, the efficacy may be less than expected and there is enhanced risk to the desirable plants. Advantages of Chemical Control: Only method available when pest reaching ETLs in the field, for immediate check (quick results). Insecticides have rapid curative action in preventing economic damage. Highly effective . Insecticides offer wide range of properties ( broad spectrum ), methods of application against different pests. High cost/benefit ratio (Economical) We can observe visible death of an insect pest. Can be used in variable climatic conditions . Wide range of chemicals and formulations available for selection. Limitations of Chemical Control: • Repeated applications may be required. • May be harmful to non-target organisms • May result in pest resistance • May result in secondary pest outbreaks (eg: carbofuran favours rice leaf folder infestsation, repeated synthetic pyrethroids application favours whitefly infestsation) • May result in pest resurgence (by killing natural enemies) • May be harmful to beneficial insects (pollinators, bees, scavangers etc) • Risky to man (Direct and indirect hazard) • Risky to livestock • May leave toxic residues in environment, leading to pollution • May leave toxic residues in foods, leading to contamination • May be phytotoxic • Bioaccumulation and biomagnification is a problem with POPs, leading to chronic health effects

Safe use of Insecticides: Pesticides are toxic to both pests and humans. However, they need not be hazardous to humans and non-target animal species if suitable precautions are taken. Most pesticides will cause adverse effects if intentionally or accidentally ingested or if they are in contact with the skin for a long time. Pesticide particles may be inhaled with the air while they are being sprayed. An additional risk is the contamination of drinking-water, food or soil. Special precautions must be taken during transport, storage and handling. Spray equipment should be regularly cleaned and maintained to prevent leaks. People who work with pesticides should receive proper training in their safe use. Precautions: The label: Pesticides should be packed and labelled according to WHO specifications. The label should be in English and in the local language, and should indicate the contents, safety instructions (warnings) and possible measures in the event of swallowing or contamination. Always keep pesticides in their original containers. Take safety measures and wear protective clothing as recommended. 198

Storage & Transport: Store pesticides in a place that can be locked and is not accessible to unauthorized people or children; they should never be kept in a place where they might be mistaken for food or drink. Keep them dry but away from fires and out of direct sunlight. Do not carry them in a vehicle that is also used to transport food. Disposal: Left-over insecticide suspension can be disposed of safely by pouring it into a specially dug hole in the ground or a pit latrine. It should not be disposed of where it may enter water used for drinking or washing, fish ponds or rivers. Some insecticides, such as the pyrethroids, are very toxic to fish. Dig a hole at least 100 metres away from streams, wells and houses. In a hilly area the hole should be on the lower side of such areas. Pour run-off water from hand washings and spray washings into the hole, and bury containers, boxes and bottles used for pesticides in it. Close the hole as soon as possible. Cardboard, paper and cleaned plastic containers can be burned, where this is permitted, far away from houses and sources of drinking-water. Packages to be buried must be made unusable and reduced in bulk as much as possible. The reuse of pesticide containers is risky and not recommended. However, some pesticide containers may be considered too valuable to be thrown away after use. Whether containers are suitable for cleaning and reuse depends on the material they are made of and what they contained. The label should provide instructions on possibilities for reuse and cleaning procedures. General Hygiene: Do not eat, drink or smoke while using insecticides. Keep food in tightly closed boxes. Use suitable equipment for measuring out, mixing and transferring insecticides. Do not stir liquids or scoop pesticide with bare hands. Use the pressure- release valve of the pump or a soft probe to clear blockages in the nozzle. Wash the hands and face with soap and water each time the pump has been refilled. Eat and drink only after washing the hands and face. Take a shower or bath at the end of the day. Protective clothing: Spraying: Spray workers should wear overalls or shirts with long sleeves and trousers, a broad-brimmed hat, a turban or other headgear and sturdy shoes or boots. Sandals are unsuitable. The mouth and nose should be covered with a simple device such as a disposable paper mask, a surgical-type disposable or washable mask, or any clean piece of cotton. The cotton should be changed if it becomes wet. The clothing should be of cotton for ease of washing and drying. It should cover the body without leaving any openings. In hot and humid climates the wearing of additional protective clothing may be uncomfortable, and pesticides should therefore be applied during the cooler hours of the day. Mixing: People who mix and pack insecticides in bags must take special precautions. In addition to the protective clothing described above, it is recommended that gloves, an apron and eye protection such as a face shield or goggles be worn. Face shields provide protection for the whole face and are cooler to wear. The mouth and nose should be covered, as recommended for indoor spraying. Care should be taken not to touch any part of the body with gloves while handling pesticides. Safe techniques: Spraying Indoors: The discharge from the sprayer should be directed away from the body. Leaking equipment should be repaired and the skin should be washed after any accidental contamination. Persons and domestic animals must not remain indoors during spraying. Rooms must not be sprayed if someone, e.g. a sick person, cannot be moved out. Cooking utensils, food and drinking-water containers should be put outdoors before spraying. Alternatively, they can be placed in the centre of a room and covered with a plastic sheet. Hammocks, paintings and pictures must not be sprayed. If furniture has to be sprayed on the lower side and the side next to a wall, care should be taken to ensure that other surfaces are not left unsprayed. Floors should be swept clean or washed after spraying. 199

Inhabitants should avoid contact with the walls. Clothes and equipment should be washed daily. Organophosphorus and carbamate compounds should not be applied for more than 5–6 hours a day and the hands should be washed after every pump charge. Blood cholinesterase activity of spray personnel should be checked weekly if fenitrothion or old stocks of malathion are used. Spraying in Fields: Spray early in the morning before the strong winds, or late in the afternoon when the wind has died down. Never apply pesticides on windy days. Do not spray when it is raining. Never eat, drink or smoke when you are spraying. Make sure other people are not near the area where you are spraying, especially children. Do not let anybody touch the plants until the leaves have dried completely. If chemicals were used to disinfect the substrate, wear gloves when filling it into containers. If no gloves are available, then let the soil sit at least five days with some, but not too much, water so that the chemicals can start to break down.

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Lecture: 32 Symptoms of poisoning, first aid, antidotes for the important groups of insecticides; insecticide resistance, insecticide resurgence, insecticide residues-importance-maximum residue limits (MRL)-average daily intake (ADI), waiting periods, important provisions of Insecticides Act 1968.

Symptoms of Poisoning, First-aid and Antidotes: • Many insecticides can cause poisoning after being swallowed, inhaled, or absorbed through the skin and eye contamination . • The properties that make insecticides deadly to insects can sometimes make them poisonous to humans. Most serious insecticide poisonings result from the organophosphate and carbamate types of insecticides, particularly when used in suicide attempts. Examples of organophosphates include malathion, parathion, diazinon, dichlorvos, chlorpyrifos, and sarin. Some of these compounds are derived from nerve gases. Pyrethrins and pyrethroids, which are other commonly used insecticides, are derived from flowers and usually are not poisonous to humans. • Symptoms may include eye tearing, coughing, and breathing difficulties. Some insecticides are odorless, thus the person is unaware of being exposed to them. Organophosphate and carbamate insecticides make certain nerves “fire” erratically, causing many organs to become overactive and eventually to stop functioning. Pyrethrins can occasionally cause allergic reactions. Pyrethroids rarely cause any problems. • The diagnosis is based on symptoms, blood tests, and a description of events surrounding the poisoning. Several drugs are effective in treating serious poisonings. Symptoms: • Organophosphates and carbamates cause eye tearing, blurred vision, salivation, sweating, coughing, vomiting, and frequent bowel movements and urination. Breathing may become difficult, and muscles twitch and become weak. Rarely, shortness of breath or muscle weakness is fatal. Symptoms last hours to days after exposure to carbamates but can last for weeks after exposure to organophosphates. • Pyrethrins can cause sneezing, eye tearing, coughing, and occasional difficulty breathing. Serious symptoms rarely develop. Diagnosis: • The diagnosis of insecticide poisoning is based on the symptoms and on a description of the events surrounding the poisoning. Blood tests can confirm organophosphate or carbamate poisoning. Treatment – First Aid: • Do not wait for help, act immediately • Act calmly and methodically. Avoid self-contamination during treatment. • Act according to the patient's needs. The highest priority is adequate breathing. It must be maintained continuously. • Terminate exposure by removing the person from the scene of spillage or other contamination. Avoid further skin contact and/or inhalation of fumes or dust. • Remove contaminated clothing quickly and completely, including footwear. Collect clothing in separate container for washing before re-use. Discard contaminated leather footwear. • Remove pesticides from skin, hair and eyes by using large quantities of water. Pay

particular attention to the washing of the eyes, hold eyelids apart and rinse thoroughly for at least 10 minutes. 201

• If no water is available, dab or gently wipe the skin with cloths or paper which should then be destroyed. Avoid harsh rubbing or scrubbing the skin. If an insecticide might have contacted the skin, clothing is removed and the skin is washed. • Place the patient on his side with the head lower than the rest of the body and turned to one side. If the patient is unconscious, keep the chin pulled forward and the head back to ensure that breathing can take place. • Particular care must be given to temperature control in unconscious patients. If the patient is extremely hot and sweating excessively, cool by sponging with cold water. If the person feels cold then cover with a sheet or blanket to maintain normal body temperature. • Induce vomiting when the chemical swallowed is highly toxic and would likely prove fatal and if medical assistance is not readily available. Vomiting can be induced by giving 15g common salt in glass of water as an emetic . If the patient is already vomiting, do not give emetic, but give large amounts of warm water. • If breathing STOPS (patient's face or tongue may turn blue), pull chin forward to avoid the tongue dropping to the back of the throat. If breathing does not occur after opening the airway, then roll the patient onto their back, keep chin pulled forward and head back. Treatment – Antidotes: • Anyone with symptoms of organophosphate poisoning should see a doctor. Atropine , given by vein (2-4 mg of atropine sulfate-intravenous), can relieve most of the symptoms. Pralidoxime , given by vein, can speed up recovery of nerve function, eliminating the cause of the symptoms. 2 PAM (pyridine aldonine methiodide), given by vein (0.5-1.0g) can also speed up the recovery. • Symptoms of carbamate poisoning also are relieved by atropine but usually not by pralidoxime. In any case, 2 PAM should be given for carbamate poisoning. • Symptoms of pyrethrin poisoning resolve without treatment. • Universal antidote: A mixture of 7g activated charcoal+3.5g magnesium oxide+3.5g of tannic acid in half-glass of warm water to absorb or neutralize the poison. • After the stomach is emptied, one of the following can be given for soothing effect ; raw egg mixed with water / butter / cream / milk / mashed potato / flour / water etc.

Insecticide Residues: Importance, MRLs, ADIs and TDDs: • Pesticide enters in the environment (soil, water or air) either through application, disposal or spill. Upon application, a number of environmental factors such as temperature, humidity, air current, light radiations, rainfall may remove the pesticide from substrate. Various degradation processes such as chemical reaction, microbial degradation or co-metabolism also dissipate pesticide from the substrate over a period of time. • Pesticides resistant to degradation by any means remain unchanged in the environment for long periods of time. The time period for which a pesticide exists in its original chemical form over the application surface and effectively controls the target organism is known as its Persistence . The most desirable pesticide would be the one that has stability just sufficient to perform its functions with no persistent residues. The ones that are most rapidly broken down have the shortest time to move or to have adverse effects on people or other organisms. And that lasting the longest, the so-called

persistent pesticides, can move over long distances and can build-up in the environment, leading to more adverse effects. 202

• The pesticide present on a surface where it was applied right after application is called deposit . Pesticide present in or on any substrate after a period of application or even without application is called residues. • WHO has defined pesticide residues as any specified substance in food, agricultural commodities, animal feed, soil or water resulting from the use of pesticides. The term includes any derivatives of a pesticide such as conversion products, metabolites, reaction products and impurities that are of toxicological significance. A pesticide when sprayed may drift over from a nearby field and fall on a crop or surface. Term pesticide residues, therefore, include residues from unknown or unavoidable sources (e.g. environmental), as well as known application of the pesticides. • The most important property of a substance to be called residue is its toxicity. Therefore, pesticide residues in/on food commodities are a matter of concern and are regulated by national and international laws. • The Codex Alimentarius Commission (which means 'food code' in Latin) establishes a code of food standards for all member nations. It was created by two UN organizations, the FAO and the WHO and has committees covering many aspects. Pesticide residues in food are dealt with by the Codex Committee on Pesticide Residues (CCPR) that works on scientific approvals made by the independent expert panel, the Joint FAO/WHO Meeting on Pesticides Residues (JMPR). • In India Ministry of Health and Family Welfare sets the standards for pesticide residues in food items (raw agricultural commodities, processed food, water) under the Prevention of Food Adulteration Act 1954 and Rules, 1955 . MRL (Maximum Residue Limit) • The legal standard for pesticide residues worldwide is Maximum Residues Limit (MRL), which is defined as the maximum concentration of a pesticide residue (expressed as mg/kg) legally permitted in or on food commodities and animal feeds. • The MRL is established by the regulatory bodies based on supervised field studies conducted at more than one agro-climatic zone as per Good Agricultural Practices (GAP), residue estimation as per Good Laboratory Practice (GLP), ADI derived from toxicological studies and food consumption pattern in a country or region (food factor). Other inputs considered during the establishment of MRL are information on daily intakes of the commodity carrying the residue besides other criteria such as health, technological, and socio-economic feasibility and its enforcement etc. The following are some examples for MRLs fixed by PFA on different commodities (further info can be downloaded from ministry of health and family welfare website, or search for prevention of food adulteration act)

Name of the Insecticide Commodity MRL (mg/kg) Carbaryl Food grains 1.5 Milled Food grains Nil Okra and leafy vegetables 10.0 Potatoes 0.2 Other vegetables 5.0 Cottonseed (whole) 1.0 Maize cob (kernels) 1.0 Maize 0.50

Rice 2.50 Chillies 5.00

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Monocrotophos Food grains 0.025 Milled food grains 0.006 Citrus fruits 0.2 Other fruits 1.0 Carrot, Turnip, Potatoes and Sugar 0.05 beet Onion and Peas 0.1 Other Vegetables 0.2 Cotton seed 0.1 Cottonseed oil (raw) 0.05 Chillies 0.2 Cardamom 0.5 Meat and Poultry 0.02 Milk and Milk products 0.02 Egg (shell free basis) 0.02 Coffee (Raw beans) 0.1

Acceptable or Tolerable Daily Intake (ADI/TDI): • The ADI/TDI for pesticide residues is the level of a substance that would have no appreciable effect on health even if ingested daily over a lifetime. The Acceptable Daily Intake, or ADI, is defined as an estimate of the amount of a food additive, expressed on a body weight basis that can be ingested daily over a lifetime without appreciable health risk. It is measured in milligrams per kilogram of body weight. The concept of the ADI was initially developed by the Joint FAO/WHO Expert Committee on Food Additives, or JEFCA. • This is derived from the most sensitive NOAEL established from the animal studies with an appropriate margin of safety, which is a factor of 100. It is expressed in mg of pesticide/kg body weight (per day). The safety margin allows for any species difference in susceptibility, the numerical differences between the test animals and the human population exposed to the hazard, possibility of synergistic action among food additives etc. While fixing the ADI, some of the other factors taken into consideration are the chemical nature of the residues, the toxicity of the chemical based on data from acute, short-term and long-term studies and knowledge of metabolism, mechanism of action and the possible carcinogenic nature of residue chemicals when consumed (usually determined in animals) and the knowledge of the effects of these chemicals on humans. In addition to the safety factor of 100, since 1996, as per the requirement of Food Quality Protection Act (FQPA), USA, an additional safety factor of 10 is used while deriving the ADI to account for the most sensitive population, viz. the children and infants. A group ADI is sometimes allocated for chemicals sharing a common structure or toxicity profile. Where ADI cannot be derived, e.g. for carcinogens, the usual recommendation is that exposure be avoided or minimized by the application of good agricultural practice and food technology. Other established references include Provisional Tolerable Weekly Intake (PTWI), Virtually Safe Dose (VSD) and health-based Maximum Allowable Concentration (MAC). The following are the examples for ADI for different insecticides set by CAC (Codex Alimentarius Commission) Name of the insecticide ADI Name of the insecticide ADI Abamectin 0.002 Acephate 0.01 Carbaryl 0.008 Carbofuran 0.01 Cyhal othrin 0.002 Chlorpyrifos 0.01 Endosulfan 0.006 Malathion 0.03 Spinosad 0.02 Methomyl 0.02

Triazophos 0.001 Imidacloprid 0.06 204

• Inorder to arrive at ADI for man, threshold daily doses (TDD) (mg/kg body weight/day) is determined using appropriate animal species, and this is then devised by a safety factor (often 10 or 100, or it may vary upto 1000) depending on the inter or intra species variation. TDD is the highest concentration / dose having no effect on any organism in that batch of test animals. Observations will be made on the changes in body weight, intake of food, composition of blood, urine, faeces, enzyme activity in serum, liver and other tissues. Behavioral changes, and after death, histological examinations will be conducted. • Correlation between ADI or TDI and MRL : Though the ADI is a daily dose expressed in mg/kg body weight (per day), the MRL is the concentration of a pesticide residue in or on the food commodities and animal feed expressed in mg/kg of the produce . Foods derived from commodities that comply with the respective MRL are intended to be toxicologically acceptable. The MRLs are derived on the basis of Good Agricultural Practice and, if adhered to, would not result in the ADI being exceeded even if all the designated crops contained the pesticide at the respective MRLs. However, if occasional samples of a commodity contain residues a little above the MRL, it does not indicate that the ADI will be exceeded. • Non Observed Adverse Effect Level (NOAEL): The important toxicological end-points from the animal studies is the non-observed-adverse-effect level (NOAEL), which is the highest concentration of a substance found by experiment or observation that causes no detectable alteration of morphology, functional capacity, growth development or life span of the target organism under defined conditions of exposure. It is expressed in milligrams of the chemical per kilogram of body weight. Pre-harvest interval (PHI) or Waiting Periods: • The time required to reduce the pesticide residues concentration below its prescribed MRL is known as Pre-harvest interval (PHI) or safe waiting period can also be calculated from residue data. PHI is then recommended by regulatory authorities in pesticide application schedules for example recommended PHI of cypermethrin formulation on brinjal crop is 1-3 days and that for carbaryl and endosulfan is 7 days. If the farmers follow good agricultural practices (GAP) and pre-harvest interval, the residues on the crop should not pose any health risk to the consumer. Decontamination of Pesticides: • Pesticide residues are unwanted even in smallest quantity because of their toxic nature. Therefore pesticide residues should be removed from the food commodity or environmental sample or be converted into non-toxic product. • For the decontamination of food commodities, simple domestic methods are found very useful. Peeling of fruits and vegetables removes residues present on the surface. Washing with water, water-charcoal suspension and alkaline water effectively removes pesticide residues. Blanching with hot water or steam detoxifies some pesticide residues. A simple dipping of fruits and vegetables in 2% salt solution for 20 minutes followed by thorough washing removes the major chunk of pesticide residues. • For the decontamination of pesticides from water it may be passed over the adsorbents such as clay or activated charcoal. Some microbes have also been utilized for the detoxification of pesticides from water. The cells of algae Prototheca zopfil and fixed films of bacterial cells on a variety of support can be used to remove a wide range of pesticides from water. Soil is the most difficult substrate to decontaminate from pesticides, as it has enormous capacity to store the pesticide. However, pesticides can be made immovable and unavailable by incorporating organic matter or activated charcoal. To accelerate the degradation of pesticides in soil, the soil is enriched with microorganisms such as bacteria, algae or fungi. These microorganisms utilize pesticides as energy source and thus degrade them in the process of co-metabolism. Cell free extract of microbial enzymes is also utilized for degrading the pesticides, mainly organo-phosphorous pesticides.

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Important provisions of Insecticide Act 1968: • An Act to regulate the import, manufacture, sale, transport, distribution and use of insecticides with a view to prevent risk to human beings or animals, and for matters connected therewith. • Central Insecticides Board (CIB): advise on matters related to (a) the risk to human beings or animals involved in the use of insecticides and the safety measures necessary to prevent such risk; (b) the manufacture, sale, storage, transport and distribution of insecticides with a view to ensure safety to human beings or animals. • Registration Committee (RC): (a) to register insecticide after scrutinizing their formulae and verifying claims made by the importer or the manufacturer, as the case may be, as regards their efficacy and safety to human beings and animals; and (b) to perform such other functions as are assigned to it by or under this Act. • The Board may appoint such committees as it deems fit and may appoint to them persons who are not members of the Board to exercise such powers and perform such duties as may, subject to such conditions, if any, as the Board may impose, be delegated to them by the Board. Provisions under Insecticide Act: • Registration of Insecticides. • Appeal against non-registration or cancellation. • Power of revision of Central Government. • Licensing officer. • Grant of License. • Revocation, suspension and amendment of license. • Appeal against the decision of licensing officer. • Central Insecticide Laboraotires (CILs) • Prohibition of import, and manufacture of certain insecticides. • Prohibitions of sale etc of certain insecticides. • Insecticide analysis. • Insecticide Inspectors. • Powers of Insecticide Inspectors. • Procedure to be followed by Insecticide Inspectors. • Report of Insecticide Analyst. • Confiscation. • Notification of Poisoning. • Prohibitions of sale etc. of Insecticides for reasons of public safety. • Notification of cancellation of Registration. • Offences and Punishment. • Defences which may be allowed. • Congnizance and trial of offence. • Offences by companies. • Powers of the Central Govt. to make rules • Powers of the State Govt. to make rules. • Protection of action taken in good faith.

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