Fumigators walking down a street in the Sultan Mosque area of Singapore and spraying a pesticide to rid the area of mosquitoes. (©Steve Raymer/Corbis. Reproduced by permission.)

Pesticides are substances or a mixture of substances, of chemical or biological origin, used by human society to mitigate or repel pests such as bacteria, nematodes, insects, mites, mollusks, birds, rodents, and other organisms that affect food production or human health. They usually act by disrupting some component of the pest's life processes to kill or inactivate it. In a legal context, pesticides also include substances such as insect attractants, herbicides, plant defoliants, desiccants, and plant growth regulators.

History of Pesticides

The concept of pesticides is not new. Around 1000 B.C.E. Homer referred to the use of sulfur to fumigate homes and by 900 C.E. the Chinese were using arsenic to control garden pests. Although major pest outbreaks have...