UNIT-V

PESTS OF SILKWORM AND MULBERRY

5.1.1: INTRODUCTION TO PEST, PARASTOIDS AND PREDATORS:

 Pest: Pest is a living organism which causes damage to the human beings or his belongings in terms of economic loss.

Example: Pests include , nematodes, mites, snails, slugs, etc. and vertebrates like rats and birds etc. The word pest id drived from French word ‘Peste’ and Latin term ‘Pestis’ meaning plague or contagious disease. Pest is any which is noxious, destructive or troublesome to man or his interests. A pest is any organism which occurs in large numbers and conflict with man’s welfare, convenience and profit. Some important definitions of pests include: 1. A pest is an organism which harms man or his property significantly or is likely to do so (Woods, 1976) 2. Insects are pests when they are sufficiently numerous to cause economic damage (Debacli, 1964) Pests are organisms which impose burdens on human population by causing (i) Injury to crop plants, forests and ornamentals (ii) Annoyance, injury and death to humans and domesticated (iii) Destruction or value depreciation of stored products. Depending upon the importance, pests may be agricultural forest, household, medical, aesthetic and veterinary pests. CATEGORIES OF PESTS Based on occurrence following are pest categories Regular pest: Frequently occurs on crop - Close association e.g. Rice stem borer, Brinjal fruit borer Occasional pest: Infrequently occurs, no close association e.g. Caseworm on rice, Mango stem borer Seasonal pest: Occurs during a particular season every year e.g. Red hairy caterpillar on groundnut, Mango hoppers Persistent pests: Occurs on the crop throughout the year and is difficult to control e.g. Chilli thrips, mealy bug on guava Sporadic pests: Pest occurs in isolated localities during some period. e.g. Coconut slug caterpillar Based on level of infestation Pest epidemic: Sudden outbreak of a pest in a severe form in a region at a particular time e.g. BPH in Tanjore, RHC in Madurai, Pollachi. Endemic pest: Occurrence of the pest in a low level in few pockets, regularly and confined to particular area e.g. Rice gall midge in Madurai, Mango hoppers in Periyakulam Parameters of population levels General equilibrium position (GEP) The average density of a population over a long period of time, around which the pest population tends to fluctuate due to biotic and abiotic factors and in the absence of permanent environmental changes. Economic threshold level (ETL) Population density at which control measure should be implemented to prevent an increasing pest population from reaching the ETL. Economic injury level (EIL) The lowest population density that will cause economic damage Damage boundary (DB) The lowest level of damage which can be measured. ETL is always less than EIL. Provides sufficient time for control measures. PEST CATEGORIES ACCORDING TO EIL, GEP AND DB (i) Key pest - Most severe and damaging pests - GEP lies above EIL always - Spray temporarily bring population below EIL - These are persistent pests - The environment must be changed to bring GEP below EIL. e.g. Cotton bollworm, Diamond backmoth (ii) Major pest - GEP lies very close to EIL or coincides with EIL - Economic damage can be prevented by timely and repeated sprays e.g. Cotton jassid, Rice stem borer (iii) Minor pest/Occasional pest - GEP is below the EIL usually - Rarely they cross EIL - Can be controlled by spraying e.g. Cotton stainers, Rice hispa, Ash weevils (iv) Sporadic pests - GEP generally below EIL - Sometimes it crosses EIL and cause severe loss in some places/periods e.g. Sugarcane pyrilla, White grub, Hairy caterpillar (v) Potential pests - They are not pests at present - GEP always less than EIL - If environment changed may cause economic loss e.g. S. litura is potentia pest in North India CAUSES OF PEST OUTBREAK Activity of human beings which upsets the biotic balance of ecosystem is the prime cause for pest outbreak. The following are some human interventions. – Reason for outbreak i. Deforestation an bringing under cultivation - Pest feeding on forest trees are forced to feed on cropped - Biomass/unit area more in forests than agricultural land - Weather factors also altered - Affects insect development ii. Destruction of natural enemies - Due to excess use of insecticides, natural enemies are killed - This affects the natural control mechanism and pest outbreak occurs, e.g. Synthetic pyrethroid insecticides kill NE. iii. Intensive and Extensive cultivation Monoculture (Intensive) leads to multiplication of pests Extensive cultivation of susceptible variety in large area - No competition for food - multiplication increases e.g. Stem borers in rice and sugarcane iv. Introduction of new varieties and crops. Varieties with favourable physiological and morphological factors cause multiplication of insects. e.g. Succulent, dwarf rice varieties favour leaf folder Combodia cotton favours stem weevil and spotted bollworm Hybrid sorghum (CSH 1), cumbu (HB1) favour shoot and gall midges v. Improved agronomic practices o Increased N fertilizer - High leaf folder incidence on rice o Closer planting - BPH and leaf folder increases o Granular insecticides - Possess phytotonic effect on rice vi. Introduction of new pest in new environment Pest multiplies due to absence of natural enemies in new area Apple wooly aphid Eriosoma lanigerum multiplied fast due to absence of Aphelinus mali (Parasit) vii. Accidental introduction of pests from foreign countries (through air/sea ports) e.g. a. Diamondback moth on cauliflower (Plutella xylostella) b. Potato tuber moth Phthorimaea operculella c. Cottony cushion scale Icerya purchasi on wattle tree d. Wooly aphid - Eriosoma lanigerum on apple e. Psyllid - Heteropsylla cubana on subabul f. Spiralling whitefly - Adeyrodichus dispersus on most of horticultural crops viii. Large scale storage of food grains Serve as reservoir for stored grain pests Urbanisation - changes ecological balance. Rats found in underground drainage Resurgence Tremendous increase in pest population brought about by insecticides despite good initial reduction in pest population at the time of treatment. o Deltamethrin, Quinalphos, Phorate - Resurgence of BPH in rice o Synthetic pyrethroids - Whitefly in cotton o Carbofuran - Leaf folder in rice o Losses caused by pests o Crop loss from all factors - 500 billion US $ annually world wide o Insect pests - 15.6% loss of production o Plant pathogens - 13.3% o Weeds - 13.2%  Parasitoids: Parasitoids are insects that parasitize other insects. The immature stages of parasitoids develop on or within its host, eventually killing it. Parasitoids may attack all stages of their host (eggs, larvae, nymphs, pupae, adults). The parasitoids are a group of insects that belong mainly to the order Hymenoptera, but also include many Diptera. They are free-living as adults, but lay their eggs in, on or near other insects (or, more rarely, in spiders or woodlice). The larval parasitoid then develops inside or on its host. Initially, it does little apparent harm, but eventually it almost totally consumes the host and therefore kills it. An adult parasitoid emerges from what is apparently a developing host. Often, just one parasitoid develops from each host, but in some cases several or many individuals share a host. Thus, parasitoids are intimately associated with a single host individual (like parasites), they do not cause immediate death of the host (like parasites and grazers), but their eventual lethality is inevitable (like predators). For parasitoids, and also for the many herbivorous insects that feed as larvae on plants, the rate of ‘predation’ is determined very largely by the rate at which the adult females lay eggs. Each egg is an ‘attack’ on the prey or host, even though it is the larva that hatches from the egg that does the eating.

Parasitoids might seem to be an unusual group of limited general importance. However, it has been estimated that they account for 10% or more of the world’s species (Godfray, 1994). This is not surprising given that there are so many species of insects that most of these are attacked by at least one parasitoid, and that parasitoids may in turn be attacked by parasitoids. A number of parasitoid species have been intensively studied by ecologists, and they have provided a wealth of information relevant to predation generally.

 Predators:

Predators capture and eat other organisms such as insects or mites. Predators include ladybird beetles, ground beetles, lacewings, syrphid (hover) flies, aphid midges (Aphidoletes) and yellow jacket wasps.

Common Predators and Parasitoids  Ladybird beetles Appearance: There are many species of ladybird beetles that vary in size, colour and pattern. Depending on species, colours are black, red, orange-red to almost yellow. Most species have coloured spots or markings on their backs. Body length: Adult - 1.0-5.0mm; Mature larva- 1.0-7.5mm Life Cycle: Overwinter as adults. Eggs (orange, elongated) are laid in clusters on underside of leaves and branches. Usually only one generation per year. Both the larvae and adults feed on pests. Insect Pests Attacked: Aphids, whiteflies, scales, mites, mealybugs and other soft- bodied insects. Monitoring: Inspect colonies of aphids for adults and/or larvae.

Fig. 1: Two spotted ladybird beetle Fig. 1.2: Multicolored Asian ladybird beetle adult

Fig. 1.3: Ladybird beetle eggs Fig. 1.4: Ladybird beetle larva

 Lacewings Appearance: Common species of lacewings include two green lacewing species, Chrysoperla carnea and Chrysopa oculata, and one brown lacewing species, Hemerobius pacifus. Lacewing eggs are white and laid singly or in groups on long stalks on the underside of leaves or branches. The brown and green lacewing larvae are very similar except for small differences in body shape and the brown lacewing's habit of moving its head from side to side while walking. Body length: Adult - 10.0-20.0 mm; Mature larva - 6.0-10.0 mm Life Cycle: Chrysoperla carnea and Hemerobius pacificus overwinter as adults; Chrysopa oculata as pupae. Up to four generations per year depending on temperature. Monitoring: Examine aphid- or psylla-infested leaves and shoots for feeding larvae or use limb taps. Insect Pests Attacked: Aphids, spider mites, whiteflies thrips, leafhoppers, scales, mealybugs, psyllids, small caterpillars and insect eggs. Green lacewing larvae feed on insect pests. Both larvae and adult brown lacewings feed on pests. Green lacewings are commercially available.

Fig. 2.1: Green lacewing adult Fig. 2.2: Brown lacewing adult.

Fig. 2.3: Lacewing eggs Fig. 2.4: Lacewing larva  Syrphid (Hover) larvae Appearance: Hover fly larvae are flattened, legless maggots with no distinct head and a tapered body. They are variously coloured (yellow, green to brown). Adults frequent flowers over which they hover before landing to feed on nectar and pollen (their only food source). They are often mistaken for bees or wasps which they mimic in colouration. Hover fly eggs are white, elongate, with fine sculpturing and are visible in aphid colonies. Body length: Adult - 8.0-15.0 mm; Mature larva - 10.0-15.0 mm Life Cycle: Overwinter as larvae, pupae, or adults depending on the species. Eggs laid on aphid-infested plant parts. Several generations per year depending on temperature and location. Insect Pests Attacked: Aphids, scales, thrips and other small soft-bodied insects Monitoring: Examine aphid-infested leaves and shoots for maggot-like larvae. Adults frequent flowers.

Fig.3: Syrphid fly larva feeding on aphid  Praying mantis Appearance: Adults are 5-10 cm long and green, brown or yellow in colour. Mantids have an elongated thorax and grasping forelegs, which they use to hold their prey while they eat. Life cycle: One generation per year. Overwinters as eggs in egg cases, which are glued to wood, bark, or other plant material. Insect Pests Attacked: Many, including aphids, flies, beetles. Feeds on pests as well as beneficials. Mantids grasp their prey with spined front legs and hold them while they eat.

Fig.4: Praying mantis adult

5.1.2: Sampling methods of pest assessment of pest-population: economic injury level and economic threshold level.

Sampling and monitoring (scouting) are fundamental components of an IPM program. Success of any sampling technique depends upon the knowledge of pest and beneficial insects Action/ economic thresholds. Important components of an insect sampling program include:

 Identification Sampling/ monitoring plan or program

 Life cycle and biology

 Injury caused

Pest Monitoring

Monitoring phytophagous insects and their natural enemies is a fundamental tool in IPM:

- for taking management decision Monitoring - estimation of changes in insect distribution and abundance

- Information about insects, life history

- Influence of biotic and abiotic factors on pest population

Pest Surveillance

Refers to the constant watch on the population dynamics of pests, its incidence and damage on each crop at fixed intervals to forewarn the farmers to take up timely crop protection measures. Three basic components of pest surveillance includes; Determination of: a. the level of incidence of the pest species b. the loss caused by the incidence c. the economic benefits, the control will provide

Pest Forecasting

Forecasting of pest incidence or outbreak based on information obtained from pest surveillance.

Uses

- Predicting pest outbreak which needs control measure

- Suitable stage at which control measure gives maximum protection

Two types of pest forecasting a. Short term forecasting - Based on 1 or 2 seasons b. Long term forecasting - Based on affect of weather parameters on pest

Objectives of Pest Surveillance

 to know existing and new pest species

 to assess pest population and damage at different growth stage of crop

 to study the influence of weather parameters on pest

 to study changing pest status (Minor to major)

 to assess natural enemies and their influence on pests

 effect of new cropping pattern and varieties on pest

Survey

Conducted to study the abundance of a pest species

Two types of survey – i) Roving survey and ii) fixed plot survey

Roving survey

- Assessment of pest population/damage from randomly selected spots representing larger area

- Large area surveyed in short period

- Provides information on pest level over large area Fixed plot survey

Assessment of pest population/damage from a fixed plot selected in a field is known as fixed plot survey. The data on pest population/damage recorded periodic from sowing till harvest. e.g. 1 sq.m. plots randomly selected from 5 spots in one acre of crop area in case of rice. From each plot 10 plant selected at random. Total tillers and tillers affected by stem borer in these 10 plants counted. Total leaves and number affected by leaf folder observed. Damage expressed as per cent damaged tillers or leaves. Population of BPH from all tillers in 10 plants observed and expressed as number/tiller.

Qualitative survey - Useful for detection of pest

Quantitative survey - Useful for enumeration of pest

Sampling Techniques

Absolute sampling - To count all the pests occurring in a plot

Relative sampling - To measure pest in terms of some values which can be compared over time and space e.g. Light trap catch, Pheromone trap

Methods of sampling a. In situ counts - Visual observation on number of insects on plant canopy (either entire plot or randomly selected plot) b. Knock down - Collecting insects from an area by removing from crop and (Sudden trap) counting (Jarring) c. Netting - Use of sweep net for hoppers, odonates, grasshopper d. Norcotised collection - Quick moving insects anaesthesised and counter e. Trapping - Light trap - Phototropic insects Pheromone trap - Species specific

Sticky trap - Sucking insects

Bait trap - Sorghum shootfly - Fishmeal trap

Emergence trap - For soil insects f. Crop samples

Stage of Sampling

- Usually most injurious stage counted

- Sometimes egg masses counted - Practical considerations

- Hoppers - Nymphs and adult counted

Sample Size

- Differs with nature of pest and crop

- Parger sample size gives accurate results

Decision Making

- Population or damage assessed from the crop

- Compared with ETL and EIL

- When pest level crosses ETL, control measure has to be taken to prevent pest from reducing EIL.

Economic Injury Level

Economic Injury Level can be defined as the lowest population density that will cause economic damage (Stern et al., 1959). In simple words, it can also be defined as a critical density where the loss caused by the pest equals the cost of control measure. EIL can be calculated using following formula; where,

EIL = C C

V x I x D x K (or) VIDK

EIL = Economic injury level in insects/production (or) insects/ha

C = Cost of management activity per unit of production (Rs./ha)

V = Market value per unit of yield or product (Rs./tonne) I = Crop injury per insect (Per cent defoliation/insect)

D = Damage or yield loss per unit of injury (Tonne loss/% defoliation)

K = Proportionate reduction in injury from pesticide used.

5.2.1: Pests of Silkworm:

5.2.1: Life cycle, symptoms of attack, period of occurrence, mode and extent of damage and control measures of Techinid Uzi fly.

In the traditional silk producing states of the country, the silkworm in larval stage is attacked by a tachinid fly ( bombycis), commonly known as uzi fly, leading to considerable decline in cocoon yield. In cocoon stage (seed / stifled / moth pierced cocoons), the silkworms are attacked by dermestid beetles (Dermestes spp.) These beetles are commonly referred to as carpet beetles. They are reported to cause considerable reduction in egg production in silkworm egg production centers (grainages).

IDENTIFICATION OF PESTS Uzi Fly: Exorista bombycis (Diptera : )  The adult Uzi fly is blackish grey in colour.  It is bigger than the common Housefly, Musca domestica and is more efficient in flight.  It has four longitudinal black stripes on the dorsum of the thorax and three cross- wise stripes on the abdomen.  Male are 11.9 mm to 12.00 mm and the female 10.20 mm to 10.40 mm in length. Width varies from 3.60 to 3.90 mm.  Wing span is about 10 mm and the wings are covered with dark grey hairs. Eyes are chocolate brown in colour.  The lateral margins of the abdomen are covered with bristles, which are thicker and longer in males than in females.

 Males can be easily distinguished from the females by the presence of external genitalia (pinkish brown in colour) at the tip of the abdomen on the ventral side and well developed tips of the legs (tarsal pads).

Fig.5.1: Adult uzi fly Fig.5.2: Female abdomen Fig.5.3: Male abdomen (Ventral) (Ventral) LIFE CYCLE OF UZI FLY  A female lays 500 - 600 eggs during her life time (18 - 22 days), each day laying about 20-30 eggs.  Eggs hatch in 48 - 60 hours.  The Maggot after hatching from the egg immediately pierces into silkworm body using the pro-thoracic hook attached to the mouth. The place of entry of maggot into silkworm body develops a black scar.  The maggot feeds on the silkworm tissues for 5-7 days during which time it moults twice.  The maggot comes out of silkworm body by creating an opening on the body (integument) and spends 12-20 hours time as post-feeding (post- parasitic) maggot and becomes pupa in dark places like cracks, crevices, corners of the rearing house, loose soil, etc.  Adult uzi fly emerges from the pupa after 10 to 12 days.

 Life cycle is completed in 17-22 days.

 Adult fly survives for 10 - 18 days (males) and 18-22 days (females).

 Adult fly feeds on pollen, rotten fruits, nectar, etc.

Post-parasitic maggot Parasitic maggot (12-20 hours) (5-7 days)

Pupa (10-12 days)

Egg (2-3 days)

Adult

Fig.6: Life Cycle of Uzi fly

Period of occurrence

 In the southern sericultural belt (Karnataka, Andhra Pradesh and Tamil Nadu), the uzi fly is prevalent throughout the year. In other parts of the country, it does not prevail throughout the year because of discontinuous rearing of silkworm and environmental extremities.

 Maximum infestation is recorded during rainy season followed by winter.

 The infestation is least during summer months.

Symptoms of attack and extent of damage

 The Uzi fly lays one or two cream coloured eggs (measuring the size of a pin head) on the silkworm larva. Generally, it prefers grown up larva (i.e., 4th or 5th instars) for egg laying.  The eggs hatch in 48 to 62 hours. A black scar is formed at the point where the egg hatches and the uzi larva (maggot) enters the body of the silkworm using the hooks (pro-thoracic hook) attached to the mouth. From this black scar, the pest attack can be identified.

 The silkworm crop loss due to this fly pest is 10-20% i.e., on an average 6 kg reduction in cocoon yield is observed for every 100 dfls of silkworm reared.

Fig.7.1: An Uzi egg on silkworm larva Fig.7.2: Adults of Uzi fly laying eggs

Fig.7.3: Black Scar on silkworm larva Fig.7.4: Uzi Maggot Fig.7.5: Uzi Pupa c) Factors responsible for outbreak of Uzi fly  Large scale and overlapping rearing of host (silkworm).  Favorable climatic conditions (temperature range of 20 – 30°C and relative humidity of 60 – 90%) facilitates continuous host / silkworm rearing which in turn helps the host availability.  Increased adult (uzi fly) longevity.  Higher egg production and egg hatchability.  Reduced activity of the natural enemies like parasitoids, predators and pathogens in nature. UZI FLY MANAGEMENT AND ITS ECONOMICS i) Management of Uzi fly Various management methods have been evolved for the suppression of the uzi fly incidence. These are classified as – o Cultural / Mechanical o Exclusion o Physical o Chemical o Biological o Legislative/Quarantine a) Cultural / Mechanical

 Silkworm rearing in a village should be conducted at a time by all farmers.

 A minimum gap of 20 days should be maintained between the two silkworm rearings.

 The cracks and crevices on the rearing house floor must be kept closed.

 Collection and destruction of uzi infested silkworm larvae.

 Collection and destruction of uzi maggots and pupae from rearing house, grainage, cocoon market and reeling establishment.

 Collection and destruction of adult uzi fly. b) Exclusion is by avoiding the contact of uzi fly with the silkworm.  Use nylon net enclosure to the rearing stand.  Fix wire mesh to windows and doors

 Provide a small ante-room at the entrance of rearing house. Cover the individual rearing tray with nylon net. c) Physical

Keep uzi trap solution in white trays near doors and windows (3 ft above ground level) both inside and outside the rearing house to trap adult uzi fly. d) Chemical  Spray / dust the ovicides like uzicide / uzipowder to kill the uzi eggs laid on silkworm body.  Spray 2% bleaching powder solution on the body of silkworm larvae to detach / kill the uzi egg. e) Biological control

 Release of Nesolynx thymus by keeping parasitised pupae ready for emergence on 2nd day after keeping packets (50 ml x 2 packets/100 dfls)  On second day of fifth instar of silkworm rearing.  Shifting of the parasitised pupa packets to places where mountages with silkworms are kept spinning. 5.2.1: Life cycle, symptoms of attack, period of occurrence, mode and extent of damage and control measures of Dermestes Beetle, ants, rodents and lizards.

 DERMESTES BEETLE

Dermestes Beetle: Dermestes spp. (Coleoptera: Dermestidae) The most important species of dermestid beetle prevalent in egg production centers is Dermestes ater. Identification of pest  Adults of D. ater are black in colour, elongate oval in shape and about 7 mm in body length.  Grubs (larvae) are also black in colour and are covered with bristles (‘hairs’).

Fig.8: Dermestes beetle

Life cycle  The female lays 150-250 eggs in the floss of the cocoons.  Egg hatching duration: 3-6 days.  Larval (grub) duration (5-7 instars): 28-40 days.  Pupal duration: 7-8 days.  Total life cycle: 38-54 days. iii) Period of Occurrence The pest prevails throughout the year. iv) Symptoms of pest attack and extent of damage  The grubs cause more damage than adults.  The infested cocoons (especially seed and stifled cocoons) show the presence of multiple irregular holes on them.  Though they show preference for feeding on the left over/dead matter in the cocoons, they do attack the green cocoons as well as the egg laying moths whenever their population gets increased.  The estimated damage level due to the beetle attack to the pupae is 16.62% and moth 3.57% with 20.19% reduction in egg production in grainages, especially those coming under government sector.

Fig. 9: Damage caused by dermestid beetles to the cocoons and egg laying silk moths v) Factors responsible for pest outbreak Storage of large quantities of moth pierced as well as stifled cocoons over a long period of time (more than 6 months). Management a) Preventive measures  Storage of rejected cocoons and perished eggs in the grainages for long period should be avoided.  The cocoon storage rooms should be cleaned periodically.  Before and after emergence of silk moth, the grainage premises should be kept clean and tidy.  Provide wire mesh to doors and windows in Pierced Cocoon (PC) storage rooms to avoid free movement of the beetles and grubs from PC storage room to grainage operation rooms. b) Control measures 1) Mechanical Collect the grubs and adults either by sweeping or by using a vacuum cleaner and destroy them by burning or dipping in soap solution. 2) Physical Exposure of beetle infested (grubs and adults) pierced / stifled cocoons packed in HDPE (black) bags to sunlight for a period of 6 hours. 3) Chemical  Wooden articles of the cocoon storage room and grainage should be dipped in 0.2% Malathion solution for 2-3 minutes. After 10 days, the trays should be thoroughly washed in water and sun dried for 2-3 days before reusing.  Store pierced cocoons in Deltamethrin treated bags (bags soaked in 0.028% Deltamethrin solution and dried in shade).  Spray 0.028% Deltamethrin solution on walls and floor of PC storage room once in 3 months.  Sprinkle commercial grade bleaching powder @ 200 gm/m2 in the PC storage room (close to wall) to prevent migration of grubs from PC storage room.

 Ants The biological name of the organism is Decophylla smaragdina belonging to the family Formicidae under the class Hymenoptera. Commonly known as Red Tree Ants. Description of the Organism: Ants are social insects living in colonies consisting of queens, males and workers. Bulks are the sterile females or workers. Males are smaller and die after mating. They make their nests in the crevices of dry twigs/ stems or in the soil. Juices secreted by the aphids attract ants. Occurrence: The ant population multiplies during summer seasons. Damage: They cause considerable loss in sericulture. About 25-30% worms lost in the initial stages is due to ants attack. How it affects: The ants attack the young age silkworms. They also attack the eggs and pupae of silkworms. Control Measures: Cleaning of bushes, destroying the nests/colony of ants is necessary before rearing. A piece of fish/meat kept near the tree base can trap the whole lot of ants and they can be killed. Apply grease ring around the tree trunk at about 1 m from the ground level to prevent crawling of ants on to the trees. Besides, sticky traps are set up to trap and kill the ants.  Rat (Rattus rattus) Rats cause serious damage to silkworm eggs, larva, pupa, cocoon and moths. Use of rat trap or poisonous baits like mixture of Plaster of Paris with flour is effective in controlling rats  Lizard (Hemidactylus flaviviridis) Lizard is another serious pest of silkworm which attacks larvae during early rearing period. Arrangements should be made to protect silkworms from lizards. Control Measures: Use traps for controlling lizards.

5.3: Mulberry pests

5.3.1: Life cycle, symptoms of attack, period of occurrence, mode and extent of damage and control measures of following pests.

5.3.1.1: Borer, girdlers with special emphasis on Rufomaculata.

A number of insects belonging to different orders attack mulberry plants. Life history, type of damage, symptoms of attack, period of occurrence and management of important pests are detailed below:

 Borer, Batocera rufomaculata DeGeer Taxonomic position Phylum: Arthropoda; Class: Insecta; Order: Coleoptera; Family: Cerambycidae; Genus: Batocera; Species: rufomaculata

Description and life history The adults are 3-5 cm in length, dark with a fine greyish vestiture, pronotum with 2 kidney shaped orange yellow spots, the basal third of the elytra with numerous black tubercles and several yellowish spots that are variable in number and shape. Fully grown grubs are cream colored with a dark brown head and are up to 10 cm long. The female cuts the tree bark and lays eggs singly into these cuts and cover with a viscous fluid. Fecundity ranges from 150-200. Eggs are shiny white in colour, oval shaped and measuring 5-7 mm long. Egg hatches within 10-15 days. On hatching the neonate grubs initially feed under the bark and then start to tunnel into the sapwood of the trunk. The grub lives for long time of about one year and hibernate in winter inside the dry shoot. When climate warms up they become active and pupate inside the stem, then adult emerge in May – June by a short tunnel running to the exterior and making a circular exit hole and start egg laying from July to August. The maximum life recorded for the adult is eight months. The adults can travel considerable distance and have good dispersal ability. A generation takes more than one year.

Fig. 10: B.rufomaculata (De Geer) Alternate host plants Mango stem borer is a polyphagous pest distributed worldwide and infesting number of horticultural crops and forest trees including mango fig, guava, jack fruit, pomegranate, apple, avocado, cashew nut, durian, eucalyptus, rubber etc. Occurrence Damage of this borer on mulberry is noticed throughout the year. Damage and symptoms Once the grub enters into the shoot, it starts feeding voraciously and creates tunnel inside the stem by boring towards upward direction. The grubs, because of their size make large tunnels of about 2-3 centimeters which interfere with sap flow and affect foliage yield at initial stages, then wilting of shoots appears and finally the plant dries. The symptoms of B. rufomaculata infestation in mulberry confuses with the symptoms of root rot. However, the frass ejected from the grub boring is occasionally visible in few plants. The grub requires stem girth of at least 6-7cm diameter to successfully develop into an adult. Therefore, it is much prevalent in older mulberry garden than younger ones which have thin stumps. In severely affected garden the exit holes of adults are often visible on the stem just above the ground level. Management Practices The mango stem borer feeds internally and thus difficult to identify their presence as well as to control, once it enter the mulberry stem /shoot. It is also because that dry shoots does not carry the pesticides to reach the grub. However following management practices need to be adopted to check the pest. Keep the mulberry garden clean and follow recommended package of practices. Exclude alternate host plants in the vicinity of mulberry garden. Monitor the presence of adult beetles in mulberry garden during summer and monsoon seasons. Collection and destruction of the beetles before egg laying helps to avoid infestation of grubs. Set light traps to attract the adult beetles. Collect and destroy the grubs which are exposed out at the time of weeding or ploughing. Mechanically remove the grubs from the infested trunk holes by using iron wire or hook. Prune and destroy the affected branches and paste the cut ends with 5% Copper Oxychloride (50 g / litre ). Clean the holes and insert cotton wick soaked in a solution of 0.5% DDVP 76% EC (5ml/ litre) and close the holes with mud plaster. The fumigant action of DDVP kills the grubs inside the trunk. Two sprays on the trunk portion with 0.04% Chlorpyriphos 20% EC (2ml/ litre) at fortnightly intervals with onset of monsoon in summer (May-June) especially to the mulberry gardens in the vicinity of mango orchard.

 Sthenias grisator F. (Cerambycidae): This insect species is commonly known as stem girdler beetle. Life Cycle: Adult deposits eggs underneath the bark of the girdled branch at night. The incubation period is about eight days. The grub tunnels into fire Wilting branches and feeds. Grubs pupate inside the tunnel. The whole life cycle lasts for 7-8 months. Adult insect is a stout built long beetle with strongly developed mouth parts. Type of damage: This beetle has a peculiar habit of ringing the stems. The bark and wood are neatly cut all around the main stem or branch leaving a clear girdle. The portion above the girdle gradually wilts and dies. Symptom: Girdled branches of the plant or wilting plants are observed in the garden. Period of occurrence: Throughout the year. Management: (i) Infested branch or stem showing the symptom of beetle attack should be cut and destroyed by buming (ii) Swabbing the base of mainstem or branches with 0.1 % BHC solution or (iii) 0. 1% Malathion emulsion prevents the attack by the beetle and safe periods are 11 days and 13 days respectively. 5.3.1.2: Defoliators: Caterpillars with special emphasis on Spodoptera litura and Diacrisia oblique.

These insect pests possess the mouth parts especially adapted to biting and chewing of various plant parts mainly leaf and shoot tissues. These pests make shot holes in leaves, skeletonize them or defoliate the entire plants. Some common biting and chewing insect pests of mulberry are caterpillars, beetles and grasshoppers. The defoliators mainly reduce the availability of mulberry leaves for silkworm rearing.  Spodoptera litura (Fabricius) Taxonomic position Phylum: Arthropoda; Class: Insecta; Order: Lepidoptera; Family: Noctuidae; Genus: Spodoptera; Species: litura. Description and life history Adult moth is stout. Fore wings dark with a strongly variegated pattern and paler lines along the veins. Hind wings white with margins having brown colour. The female moths lay eggs in clusters of 200-300 on the underside of leaves and cover them with thick brown scales. Eggs hatch in 4-5 days. The larva is hairless and variable in colour. Final instar caterpillars are 50 mm in length, pale greenish brown in color, stout, cylindrical with transverse and longitudinal grey & yellow bands. The older larvae are night-feeders (nocturnal) and are usually found in the soil around the base of plants during the day. The larval period lasts for 2-3 weeks. They form dark brown pupa in earthen cocoon in the soil which lasts for 2 weeks. The moths are stout, dark with waxy white markings having a brown colour. They are attracted towards light during night. Life cycle takes 30- 40 days to complete with 8 generations in a year. Alternate host plants Cutworm is a polyphagous pest with a wide host range. Important host plants include tobacco, tomato, castor, beet root, carrot, cauliflower, capsicum, potato, radish, cotton, soyabean, cabbage, chickpea, sun flower, mustard, okra, maize, sorghum etc. Occurrence The cutworm incidence occurs from August to February, mainly in winter season. Damage and symptoms The caterpillars attack shoots of young mulberry plants and cut them, hence the name cutworm. The cut portion of the shoot dries up and falls off. They also feed on mulberry leaves voraciously. In heavily infested mulberry gardens, the plants are seen without branches and sometimes with dried leaves. Management Practices Collect and destroy egg masses and young caterpillars. Plough infested garden and dig near the base of mulberry plants to expose the pupae present in the soil to sunlight and predators. Install light traps to attract and kill the adult moths. Use Spodolure, a pheromone trap @ 2 lures/acre twice at an interval of 15 days from 25th day after pruning to attract and kill male moths Spray 0.15% DDVP 76% EC (2 ml/litre) during evening hours, 20 days after pruning. Safe period is 15 days. S. litura is known to be attacked by many natural enemies at various life stages. However release of the egg parastoid, T. cholonisim is m o s t promising.  Bihar hairy caterpillar, Spilosoma obliqua Walker Taxonomic position Phylum: Arthropoda; Class: Insecta; Order: Lepidoptera; Family: Arctiidae; Genus: Spilosoma; Species : obliqua. Description and life history Bihar hairy caterpillar is a major pest in south India. The female moth lays about 1200 green eggs in clusters on the underside of leaves which hatch in 5-7 days. Body of the newly hatched larvae is dull white in color with small dense hairs and the head is black in color. The anterior and posterior part of the caterpillar is black and the middle part is yellowish brown in color. Fully grown caterpillar attains 5 cm in length. The larval stage takes 27-31 days out of which final instar itself is 5-7 days. Pupation takes place close to mulberry plants in loose soil or leaf litter and it is dark brown in color and measures 2 cm in length. The moth emergence takes place in about 12-14 days. The adult moths are light brown in color with brick red abdomen and having black dots on dorsal side arranged in rows. The wings also possess scattered black dots. The life cycle is completed in about 45-50 days. Alternate host plants It is a polyphagous pest with a wide host range. Important host plants include amaranthus, cowpea, jatropha, groundnut, jute, sunflower, castor, cotton, green gram, bengal gram, maize, sunnhemp etc. Occurrence Incidence of Bihar hairy caterpillar, S. obliqua in mulberry starts with the onset of monsoon. It occurs throughout the year in certain pockets. Peak infestation is seen during March to April and July to November. Damage and symptoms Gregarious young caterpillars feed upon the chlorophyll layer mostly on the under surface and skeletonize the leaves. However, late age caterpillars are voracious feeders, consume entire leaf and cause loss by way of defoliation. In severe cases, only stems are left behind. Management practices Collect the egg masses, caterpillars, affected leaves and destroy them by dipping in 0.5% soap solution or by burning. Follow deep ploughing or digging so as to expose the pupae present in the soil to predatory birds and scorching sun. Flood irrigation also helps in destroying the pupae in the soil. Install light traps to attract and kill the adult moths. Spray of 0.1% Dimethoate 30 % EC (safe period 20 days) or 0.15% DDVP 76% EC 20 days after pruning (safe period15 days). Release T. chilonis @ 4 cards per acre, a week after the spray of insecticide. Do not spray any insecticide after the release of parasitoids. 5.3.2: Mode and extent of damage and control measures of following pests.

5.3.2.1: Grasshopper, Jassids

 Wingless grasshopper, Neorthacris acuticeps nilgriensis Uvarov Taxonomic position Phylum: Arthropoda; Class: Insecta; Order: Orthoptera; Family: Acrididae; Genus:Neorthacris; Species: acuticeps nilgriensis. Description and life history As the name indicates, the adult grass hoppers are wingless, however, as the hind legs are very strong they are capable of jumping to a long distance. Females are larger than males. Each female lays 6-8 egg pods (each egg pod with 8 to 18 eggs) in soil at a depth of about 3 inches. They hatch in about 28-31 days. The nymphs take 90-95 days to become adults which live for 45-60 days. Thus the total life cycle takes 5-6 months. Alternate host plants: Sunflower, finger millet, groundnut, beans, potato etc.

Occurrence Incidence of this pest coincides with onset of monsoon and continues till post monsoon periods. However, peak infestation occurs during October and declines subsequently with no occurrence from January till onset of monsoon. Damage and symptoms Both nymphs and adults feed voraciously on sprouting buds and leaves of mulberry. Sometimes, they also feed on green bark of affected plants. Branches of plants without leaves are observed in the mulberry garden in case of severe incidence. Management practices  During early morning hours, they are less active and hence can be collected and destroyed.  Deep ploughing immediately after the onset of monsoon to expose egg masses to sunlight and predators.  Field sanitation by keeping mulberry garden free from weeds which serves as alternate host plants.  Spray 0.076% DDVP 76 % EC (1 ml/ litre) on mulberry foliage to kill the nymphs and adults. If infestation is severe, need second spray, 10 days after first spray. Safe period is 15 days.  While spraying, take precaution to see that they will not jump and escape to neighbouring mulberry gardens. For this, spray in concentric circle manner for few rounds so that they will be trapped in some corner.

Fig.11: N.acuticeps nilgriensis  Jassid, Empoasca flavescens Fabricius Taxonomic position Phylum: Arthropoda; Class: Insecta; Order: Hemiptera; Family: Cicadellidae; Genus: Empoasca; Species: flavescens. Description and life history Adults are pale green or greenish yellow in color and about 3-4 mm in length. Body is wedge-shaped with whitish markings on the head and thorax. The head is prolongated forward as a smooth, flat, triangular structure with a pair of antennae possessing sensoria. The thorax is simple and abdomen is tapering at the posterior end. The hind legs have two parallel rows of spines which extend all along the hind tibiae. The wings are held like a roof over the abdomen. The nymphs resemble adults, but they lack wings until the fourth instar. Adults and nymphs move sideways. Female lays 20-30 eggs on the lower surface of the leaves below the epidermis. Eggs are pale yellow in color & elongated in shape. The egg hatches into nymph within 6-13 days. The nymph undergoes five instars and becomes adult in 8 to 22 days. Nymphal period is 19-27 days. Pupation takes place on the leaf itself. There are 10-12 generations in a year. Alternate host plants Castor, tea, okra, cotton, beans, brinjal, potato etc., are prone to severe attack of jassid. Occurrence It is considered to be a minor or occasionally serious pest of mulberry. The insect remains active throughout the year, but maximum population build up occurs during November to January, that is mostly in the winter season. Damage and symptoms Both nymphs and adults damage the plant by sucking the sap of young leaves and tender shoots. At the time of sucking cell sap inject toxins in to the plant tissues. The early symptoms are the appearance of yellow or brown patches at the margin of the leaves followed by distortion of leaf veins. Finally, leaves curl upward becoming cup shaped, margins turn brown, dry and wither off prematurely. This characteristic symptom is known as “Hopper burn”.

Fig. 12: Nymph & adult stages of Jassid Management practices Set up light traps and yellow sticky traps to destroy adult population. Sprinkler irrigation is effective in controlling the pest. Spray neem oil (3%) with fish oil rosin soap (2%). Safe period is 10-12 days. Spray of a strong jet of water in the affected mulberry garden help to reduce the pest population below the economic injury level. Cultivation of cluster bean, cowpea, black gram or groundnut as intercrops in mulberry encourage to buildup natural enemies like coccinellids and spiders. Spray 0.1% Dimethoate 30% EC (3ml/litre). Safe period is 25 days. 5.3.2.2: Suckers, Mealy bug, Scale insects, thrips and mites. Suckers: Sap suckers are commonly known as sucking pests which have piercing and sucking type mouth parts with slender needle like stylet to pierce the plant cell from leaves or stems and suck the juice. In mulberry, the sap suckers deplete nutrient value of the leaves and cause stunted growth of plants. Majority of sucking pests secrete honey dew which promote growth of black sooty mold, a type of fungus that pollutes the entire mulberry garden and makes the leaves unpalatable in case of severe incidence. Some sucking insects inject toxic materials into the plant while feeding, which leads to wilting of plants whereas few act as vector and transmit plant diseases. Common sap-feeders include thrips, mealy bugs, whiteflies and scale insects. Among non-insect pests, few mite species are recorded on mulberry and they also suck the plant sap.  SAP SUCKERS: Pink mealybug, Maconellicoccus hirsutus (Green) Taxonomic position Phylum: Arthropoda; Class: Insecta; Order: Hemiptera; Family: Pseudococcidae; Genus: Maconellicoccus; Species: hirsutus. Description and life history Adults of both female and male are about 3 mm long. Females are pink in color with a white waxy covering and have no wings. Males have a pair of wings and two long waxy tails and are capable of flight. Female can reproduce parthenogenetically and each female lays approximately 350-600 eggs in an ovisac covered with cotton like mealy substance. The eggs will hatch in 6-9 days. Males have four nymphal instars while females have only three. Nymphal period lasts for 23-27 days and total lifecycle completes in a month period. There will be 10-12 generations in a year. Alternate host plants They are highly polyphagous and so far more than 350 host plants have been recorded in the world. Important host plants are hibiscus, beans, pumpkin, croton, chrysanthemum, citrus, grapevine, guava, coffee, sugarcane, soybean, mango, pigeon pea, maize, cotton, teak etc. Occurrence They occur on mulberry throughout the year, but the incidence is high in summer months (March to August). Their population is negligible during rainy season. Damage and symptoms The nymphs feed by sucking the sap from tender leaves and stem portion. Hence the affected apical shoots show bunchy appearance due to curling of leaves, shortening of internodes and thickening of stem. This symptom is popularly known as 'Tukra' in India. In advance stages of infestation black sooty mould is developed in the affected area due to growth of fungus on the honeydew secreted by the mealy bug. The pest makes both quantitative and qualitative loss in mulberry production due to retarded growth of plants and depletion in nutritional value of the leaves. Management practices Clip off infested apical shoots and destroy by burning or dipping in soap solution. Do not grow alternate host plants of the mealy bug in the vicinity of mulberry gardens. Spray 0.05% Dimethoate (36 % EC) 12-15 days after pruning. Safe period to silkworm is 20-25 days. During summer second dose of 0.2% DDVP (76% EC) 10 days after first spray is essential to avoid recurrence of the pest during growing phase of mulberry plants. Safe period is 15-17 days. Release predatory ladybird beetles Cryptolaemus montrouzieri @ 250 adults or Scymnus coccivora @ 500 adults /acre/ year in two split doses at an interval of six months.

Fig. 13.1: Pink mealy bug Fig.13.2: C. montrouzieri feeding on pink mealy bug  Mulberry thrips, Pseudodendrothrips mori (Niwa) Taxonomic position Phylum: Arthropoda; Class: Insecta; Order:Thysanoptera Family: Thripidae; Genus: Pseudodendrothrips; Species: mori. Description and life history Mulberry thrips reproduce both sexually and parthenogenetically. Each female lays about 30-50 bean shaped whitish eggs measuring 0.25 mm in length and 0.10 mm in breadth on ventral surface of tender leaves which hatch in 6-8 days. The newly hatched first instar nymph is initially colourless and transparent with a pair of dark red compound eyes and gradually changes to light creamy yellow. There are two nymphal stages with 6-7 days. Second instar nymph measures about 0.70 mm length and 0.23 mm breadth. After nymphal stages, it enters into soil and become inactive and non- feeding stages called pre-pupa and pupa. The pupa is yellow coloured, characterized by two pairs of short wing pads. Adults are about 0.8 mm long. Female is yellow in colour, while male is darker. Total lifecycle is completed in 20-22 days with 15 generations in a year. Alternate host plants Very few plants like Ficus, Tridax procumbens, Camellia sinensis, Leersia hexandra are reported as alternate hosts of P. mori. Occurrence Occurs throughout the year, but incidence is severe in summer months (April – May) and least in rainy season (October- November). Damage and symptoms Nymphs and adults are found mainly on the underside of the leaf. They pierce the epidermis of mulberry leaves using their lacerating mouthparts and extract the plant sap. During laceration, they secrete saliva which coagulates the sap resulting in the formation of white streaks in the early stage followed by silvery blotches which are mixed with small black spots of thrip faeces. This symptoms helps in distinguishing damage by P. mori from that caused by other mulberry pests. As the leaf tissue dries beneath the epidermis the silvery patches turn brown and become depressed. In acute cases serious drying of the leaf tissues results in leaf curl and these leaves shrink harden and ultimately fall. Stunting, leaf curling and deformation are also observed in severely affected gardens. Feeding thrips affected mulberry leaves to silkworm results in adverse impact on economic traits and cocoon yield. Management practices  Mulberry field should be thoroughly cleaned after harvest by removing small side branches, dead leaves and weeds in order to eliminate any developmental stages of thrips on them.  Periodical ploughing and digging of mulberry field helps in exposing the thrips pupae to hot sun and natural enemies.  Water jetting or sprinkler irrigation is effective in reducing thrips population.  Providing frequent irrigation helps in increasing the pupal mortality in soil thereby reducing the thrips emergence.  Spray of 0.1% Dimethoate 30% EC (3ml/litre) 15 days after pruning. Safe period is 20-25 days.  Release of S. coccivora @ 500 adults or Chrysoperla @ 1000 eggs / acre, a week after the insecticide spray. 5.3.2.4: Termites.  Termites, Odontotermes sp. Taxonomic position Phylum: Arthropoda; Class: Insecta; Order:Isoptera Family: Termitidae; Genus: Odontotermes. Description and life history Termites or white ants are soil inhabiting social insects. They are found in all types of soils but frequent in sandy and red loamy soils. They live in colonies with different casts such as workers, soldiers and queen. The queen has a very large abdomen and lays about 75,000 eggs in a day. Eggs hatch in 24 to 90 days. Duration of development of young ones vary with casts and environmental conditions. The reproductive casts mature in 1-2 years and there will be only one queen per colony which lives for 5-10 years. The queen is fed by the workers and is confined to royal chamber with king. Theking's life is very shorter than that of queen. When the king dies, a new one replaces it. The workers usually develop from fertilized eggs but remain stunted as they feed on ordinary food. The workers perform all the works except reproduction and defence. The soldiers develop from unfertilized eggs and remain under developed. They defend the colony against enemies such as ants and other predators. Alternate host plants Termites are highly polyphagous insects attacking all most all the agricultural, horticultural and forest tree plants. Occurrence They occur when rain recede or from October onwards and continues till the onset of monsoon rains. Damage and symptoms Termite damage is mainly observed in rainfed gardens. In mulberry nursery and new plantation, they attack below ground portion. They feed on the bark and hard wood. Hence, cuttings dry up and no sprouting takes place. In old plantations, they first infest the dry twigs. Later they slowly move to live twigs. They form foraging galleries inside the main stem and extending below the ground. In case of pruned plants they form a sheath around the twigs and feed on them. Thus they affect the sprouting buds.

Fig.14: Termite attack on mulberry plants Management practices  Remove the dead and dried twigs and leaves.  Flood irrigation help in keeping termites away.  Locate the termite mounds if any nearby mulberry gardens and destroy by breaking mounds and kill the queen. When once the queen is killed or destroyed the colony gets abandoned by them.36  Prepare a solution of Chlorpyriphos 20% EC @ 3ml/litre and pour into the mound followed by closing the mound hole with wet earth.  In established plantation, soil drenching with 0.1% Chlorpyriphos 20% EC to be practiced.  Treat the mulberry cuttings with 0.1% Chlorpyriphos 20 % EC solution before planting.