What are pesticides?

Pesticides are chemicals that are used to control pests, such as insects, rats, weeds and moulds. In most cases, these chemicals are poisons that kill the pest, but in some cases they act as a repellent (i.e. odors that make the pests stay away), or they stop the pest from growing and reproducing.

Caterpillars can be pests of the crops. Farmers use pesticides to kill these insects.

Pesticides are sprayed on crops in attempts to control insects, fungi and other pests.