🐞 Pesticide Groups and Classification

This lesson explains how pesticides are grouped for field use and exam clarity, including classification by target organism, mode of entry, mode of action, and chemical nature. Use this structure to select safer, purpose-specific control options within integrated pest management.

Pesticide Groups

Groups of pesticides : The pesticides are generally classified into various groups based on pest organism against which the compounds are used, their chemical nature, mode of entry and mode of action.

Based on organisms

a) Insecticides : Chemicals used to kill or control insects (eg.) endosulfan, malathion

b) Rodenticides : Chemicals exclusively used to control rats (eg.) Zinc

phosphide

c) Acaricides : Chemicals used to control mites on crops / animals (eg.) Dicofol

d) Avicides : Chemicals used to repel the birds (eg.) Anthraquionone

e) Molluscicides : Chemicals used to kill the snails and slugs (eg.) Metaldehyde

f) Nematicides : Chemicals used to control nematodes (eg.) Ethylene

dibromide

g) Fungicides : Chemicals used to control plant diseases caused by fungi

(eg.) Copper oxy cholirde

h) Bactericide : Chemicals used to control the plant diseases caused by

bacteria (eg.) Streptomycin sulphate

i) Herbicide : Chemicals used to control weeds (eg.) 2,4, - D

Based on mode of entry

a) Stomach poison : The insecticide applied in the leaves and other parts of the

plant when ingested, act in the digestive system of the insect and bring about kill (eg.) Malathion. b) Contact Poison : The toxicant which brings about death of the pest species by

means of contact (eg.) Fenvalerate. c) Fumigant : Toxicant enter in vapour form into the tracheal system (respiratory

poison) through spiracles (eg.) Aluminium phosphide d) Systemic poison : Chemicals when applied to plant or soil are absorbed by

foliage (or) roots and translocated through vascular system and cause death of insect feeding on plant. (eg.) Dimethoate.

Based on mode of action

a) Physical poison : Toxicant which brings about kill of one insect by exerting a

physical effect (eg.) Activated clay.

b) Protoplasmic poison : Toxicant responsible for precipitation of protein (eg.)

Arsenicals. c) Respiratory poison : Chemicals which inactivate respiratory enzymes (eg.)

hydrogen cyanide. d) Nerve poison : Chemicals inhibit impulse conduction (eg.) Malathion. e) Chitin inhibition : Chemicals inhibit chitin synthesis (eg.) Diflubenzuron.

Classification based on chemical nature of insecticides

Pesticides

pesticides

pesticides

oils origin origin organic compiunds

1.Organo 2 Cyclodiene 3 Organo 4 Carba- 5 Synthetic 6 Miscellchlorine . compounds . phos- . mates . pyrethroids . aneous phates groups

I.Inorganic pesticides

Inorganic chemicals used as insecticides Eg. Arsenic, Fluorine, Sulphur, lime sulphur (Insecticides) zinc phosphide (Rodenticide)

II.Organic pesticides

Organic compounds (constituted by C, H, O and N mainly) Hydrocarbon oil (or) Petroleum oil – eg. Coal tar oil, kerosine etc., Animal origin insecticides – eg. Nereistoxin extracted from marine annelids –

commercially available as cartap, padan. Plant origin insecticides : Nicotine from tobacco plants, pyrethrum from Chrysanthemum flowers, Rotenoids from roots of Derris and Lonchocarpus Neem – azadirachtin, Pongamia glabra, Garlic etc., Synthetic organic compounds : These organic chemicals are synthetically produced in

laboratory.

i. Chlorinated hydrocarbon (or) organochlorines

Eg. DDT, HCH, Endosulfan, Lindane, Dicofol (DDT, HCH banned) ii. Cyclodienes

Eg. Chlordane, Heptachlor (Banned chemicals) iii Organophosphates : (Esters of phosphoric acid)

.

Eg. Dichlorvos, Monocrotophos, Phospamidon, Methyl parathion, Fenthion, Dimethoate, Malathion, Acephate, Chlorpyriphos iv. Carbamates: (Derivatives of carbamic acid)

Eg. Carbaryl, Carbofuran, Carbosulfan v. Synthetic pyrethroids ; (Synthetic analogues of pyrethrum)

Eg. Allethrin, Cypermethrin, Fenvalerate vi. Miscellaneous compounds

Neonicotinoids (Analogues of nicotine) eg. Imidacloprid Spinosyns (Isolated from actinomycetes) eg. Spinosad Avermectins (Isolated from bacteria) eg. Avermectin, Vertimec Fumigants : Eg. Aluminium phosphide, Hydrogen cyanide, EDCT

Summary Cheat Sheet

• Pesticides are commonly classified according to the organism they are meant to control.

• Important groups include insecticides, acaricides, rodenticides, avicides, molluscicides, nematicides, and fungicides.

• Remembering classification by target organism is a common exam-oriented pest-control concept.

• Review core concepts, definitions, and field-level application points from this lesson.

• Prioritize economic threshold-based decisions and integrated management logic where relevant.