what is pesticide

A pesticide is a chemical or biological agent that is used to control pests, which can include insects, plant pathogens, weeds, mollusks, birds, mammals, fish, nematodes, and microbes that destroy property, cause nuisance, or spread disease. Pesticides are unique among toxic substances because they are purposely introduced into the environment to manage pests. According to the Environmental Protection Agency (EPA), a pesticide is any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest. This includes insecticides, herbicides, fungicides, and various other substances used to control pests. Adjuvants, which are compounds added to improve the effectiveness of a pesticide, are also regulated as pesticides in California. Pesticides can be harmful to other organisms, including humans, and need to be used safely and disposed of properly.