n. a chemical agent used to kill insects or other organisms harmful to crops and other cultivated plants. Some pesticides, such as *parathion and *dieldrin, have caused poisoning in human beings and livestock after accidental exposure.
Any substance or mixture of substances intended for preventing or controlling unwanted species of plants and animals. This includes any substances intended for use as plant-growth regulators, defoliants or desiccants. The main groups of pesticides are: herbicides to control weeds; insecticides to control insects; and fungicides to control or prevent fungal disease.... pesticides
Health Encyclopedia