Pests

• that affect comfort, health convenience and profits of man. • They cause damage to cultivated plants, stored grains, clothing, books, furniture, domestic etc. Pests of paddy- Leptocorisa acuta

• Rice bug • Breen/light brown • Emits a foul smell • 6 legs, 1 pair antenna • 24-30 3ggs in raw • Nymph to adult in 15-18 days • Adult life span 33-35 d • Attack paddy in milky stage • DDT/BHC of coconut- Oryctes rhinoceros

• Rhinoceros beetles • Horn on head • Eggs deposited in manure • Eggs-grubs (curved)-pupa- adult • Adult bore through the unopened tender coconut leaves and chew • Destroy grubs from the breeding ground Pest of cotton- Earias fabia

• Spotted boll worm • Green • Eggs on buds/shoots • Larva bore shoots and bolls. • Shoots/bolls dry and drop • Pupa-adult

Pests of - perpusilla

• Sugarcane leaf hopper • Agult: pale straw coloured , 1cm • Head with a prolonged snout • Suck the sap from leaves-yellowing Control of pests

1. Chemical control 2. Biological control 3. IPM Chemical control

• method of pest control is the use of pesticides. • Pesticides are chemicals synthetic chemicals that either kill the pest or inhibit their development. • Pesticides are classified according to the pests the used to control- Fungicides, Insecticides, Herbicides,Rodenticide

Types of pesticides

1. Stomach poisons: Eg: Lead arsenate, Calcium arsenate. 2. Contact Poisons:. Eg: DDT, BHC. 3. Fumigants: Are poisonous gases. They enter the body through spiracles and kill . They are used in closed rooms. Eg: Aluminium phosphide, Naphthalene

• Adv • Disadv • fast acting and effective • bioaccumulation (and • Most of them are broad- biomagnifications spectrum chemicals • Affects human beings • kill insect pests of all life health stages (egg, larva and • Insects develop adult) insecticide resistance • It is readily available in the • Kills useful insects like market,. pollinators and natural enemies.

Biological control

• Definition: The action of biocontrol agents (natural enemies) against the target species to keep the pest below economic threshold level (ETL). • In other words, it is a practice in which an organism is used against another organism. • e.g., of mosquitoes by fishes which feed on their larvae four types of pest control:

(i) Classical biological control or importation,

(ii)Augmentation-in order to supplement an existing population, 1. Inoculation-throughout the year. 2. Inundation, which the release of large numbers of natural enemy, with the aim of killing those pests present at the time The natural enemies of insect pests include

• Predators: They are free living species which consume a large number of prey during their life time. • Eg: ladybird beetle, Rodolia cardinalis, commonly called vedalia, has been used to control the cottony- cushion scale insect (Icerya purchasi), a pest of citrus trees.

• species whose immature stages develop on or within the body of the insect-Egg parasitoids, larval parasitoids and adult parasitoids based on which stage of the host is attacked by that particular • Eg: Trichogramma & Apanteles

Pathogens: • disease causing organisms that include Bacteria, fungus and virus. They are very species specific. • Bacteria: Bacillus thuringiensis is a spore- forming bacteria that infects a variety of insects, including the larvae of moths, butterflies, flies, and beetles.

• contains a toxic protein called crystal protein or Cry protein, when ingested by the insect pest, gets activated in the alkaline midgut of it , causing cell lying and eventual death of the insect.

• Fungi: The most commonly used in insect control are Beauvaria bassiana Metarrhizium anisopliae. • Virus: called inclusion viruses- first multiply in the nuclei, but later continue to replicate in the cytoplasm of the pest. The disease eventually kills the insect. • Eg: NPV (nuclear Polyhedrosis virus)

Advantages of Biological Control

• It is specific to a particular species • Environment friendly • cost effective in the long run. • Because the predator introduced will be naturally inclined to target the pests Disadvantages of Biological Control

• Since it is species specific, it cannot control different species of pests at the same time. • It's a slow process. • Predators can only survive if there is something to eat, so destroying their food population would risk their own safety. Therefore, they can only reduce the number of harmful pests. • While it is cheap in the long run, the process of actually setting up a biological control system is a costly endeavor. • It is not readily and easily available in the market. • It has a very less shelf life METAMORPHIC PATTERNS IN INSECTS METAMORPHIC PATTERNS IN INSECTS

• a rapid and complete transfor•mation from an immature larval life to a sexually adult form involving morphology, function and habitat changes”. • Ecdysis/moulting • Stadium • Instar Types of Metamorphosis:

1. AMETABOLOUS development 2. METABOLOUS development I. Gradual Metamorphosis or Paurometabolous Development II.Incomplete Metamorphosis or Hemimetabolous Development III.Complete Metamorphosis or Holometabolous Development: IV.Hypermetamorphosis or Hypermetabolous Development

AMETABOLOUS development

Complete Metamorphosis or Holometabolous Development