Introduction to Pesticides and Their Classification

Use or target pests are what determines which pesticide is used.
Pesticides are classified based on their mode of action.
Toxicity is a major factor influencing what pesticide can and cannot be used.
Pesticides have distinct chemical structures and compositions that differentiate them from one another.

Acaricides are used to kill mites and ticks. Examples include DDT, dicofol, and Fenpyroximate.
Antifeedants prevent pests from feeding. Examples include Chlordimeforn, Fentin and Azadirachtin.
Bactericides kill or inhibit bacteria in plants or soil. Examples include Copper hydroxide, Kasugamycin, Streptomycin, and Tetracycline.
Fungicides prevent, inhibit, or eradicate fungi. Examples include carbendazim, thiabendazole, and thiophanate-methyl.
Chemosterilants sterilize insects, rendering them unable to reproduce. Examples include Aziridinyl and Diflubenzuron.
Herbicides kill or inhibit the growth of plants, particularly weeds. Examples include Paraquat, Glyphosate, and 2,4-D.
Insecticides kill or inhibit the growth of insects. Examples include Monocrotophos, Carbofuran, and Lambdacyhalothrin.
Nematicides are used to control nematodes. Examples include Abamectin.
Rodenticides are used to kill rats and related animals. Examples include Zinc Phosphide and Bromadiolane.

Contact Pesticides are applied directly to the target pest, killing it on contact.
Stomach Pesticides are ingested by the pest, killing it from the inside.
Systemic Pesticides are absorbed by the plant and move throughout its system, killing pests that feed on it.
Translaminar Pesticides move through the plant's outer layer and tissues, protecting against insect pests.
Fumigant Pesticides are vaporized and applied to a space or sealed area, killing pests through inhalation.

Pesticides are classified by their chemical structures as well as mode of action.

Natural Organic Insecticides are derived from natural sources, such as plants or microorganisms. They are divided into categories like Microbial bio-pesticides and Botanical Pesticides.
Microbial bio-pesticides are derived from bacteria, fungi, and viruses, used to control pests. Examples include Antagonistic and Entomotoxic Bacteria, Antagonistic and Entomopathogenic Fungi, Nuclear polyhydral virus, and Baculovirus.
Botanical Pesticides are derived from plants. Two major examples are Azadirachtin and Pyrethrin.
Synthetic Organic Insecticides are produced artificially through chemical synthesis. These are subdivided into many categories including Organochlorine Pesticides, Organophosphate Pesticides, Carbamates, Synthetic-pyrethroid, and Other Insecticides.

Chlorinated hydrocarbons are a class of synthetic organic insecticides with several effects, including insecticidal actions.
Examples include DDT, Aldrin, Dieldrin, Endrin, Chlordane, Heptachlor, Lindane, and Toxaphene.

Organophosphorus insecticides are a class of synthetic organic insecticides with several effects, including anti-cholinesterase actions.
They are rapidly metabolized in the body and have an acute toxicity effect.
Examples include Malathion, Parathion, Methyl Parathion, Diazinon, Fenthion, Chlorpyrifos, and Dichlorvos.

Carbamates are a class of synthetic organic insecticides with several effects, including anti-cholinesterase actions. They are less toxic than organophosphates.
Examples include carbaryl, aldicarb, propoxur, and methomyl.

Pyrethroids are a class of synthetic organic insecticides with several effects, including knockdown action. They are less toxic than organophosphates and carbamates.
Examples include permethrin, cypermethrin, deltamethrin, and fenvalerate.

There are many other insecticides, including:
Neonicotinoids are a new class of insecticides with nicotinic receptor agonist action. Examples include imidacloprid, acetamiprid, nitenpyran, dinotefuran, thiamethoxam, thiacloprid, and clothianidin, with imidacloprid being the most widely used.
Insect Growth Regulators disrupt normal insect development. Examples include juvenile hormone analogs, anti-juvenile hormone agents, and ecdysteroids, all of which have different effects depending on their chemical structure. Examples include methoprene, kinoprene, hydroprene, pyreproxyfen, fenoxycarb, tebufenozide, halofenozide, and methox.