Pesticides may be a chemical substance or biological agent used against pests including insects, plant pathogens, weeds, molluscs, birds, mammals, fish, nematodes and microbes that compete with humans for food, destroy property, spread disease or are a nuisance.
Pesticides are of two types: Natural and Synthetic
First commercial pesticide was discovered by Millardet (1882). It is called Bordeaux mixture.
Example of Natural Pesticides:
- Azardirachtin obtained from natural insecticides seed of Azardiracta indica (neem) destroys Japanese beetles and other leaf eating insects.
- Rotenones obtained from roots of Derris elliptica and Lonchocarpus is harmless to warm blooded animals.
- Squilla obtained from red squilla.
- Nicotine obtained from Nicotiana species.
- Pyrethrin obtained from floral heads of Chrysanthemum species used in fly spray, aerosols, mosquito coils.
- Thurioside obtained from Bacillus thuringensis effective against moths flies, mosquitoes, beetles.