use of pesticides

• • Chemicals used to kill pests of plants and animals, including pathogens and the vectors that transmit pathogens between organisms. 
• • However, overuse of pesticides has led to pests developing resistance. This means new pesticides need to be developed. 
• • Also, the use of pesticides has damaging effects on the environment, e.g. kills non- target species including beneficial insects such as bees, and bioaccumulation of toxic chemicals (levels increase up the food chain).