A pesticide is a chemical substance used to control or eliminate unwanted plants, insects and other pests that can damage crops, livestock or human health. Pesticides are widely used in agriculture to protect crops from damaging insects and diseases, but they also have many non-agricultural uses such as vector control (preventing the spread of disease by controlling vectors like mosquitoes), forestry and urban pest control. The term "pesticide" includes herbicides, insecticides, fungicides, rodenticides and other similar substances used to control pests.