A pesticide is any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any pest. Pests can be insects, mice and other animals, unwanted plants (weeds), fungi or microorganisms like bacteria and viruses. Though often misunderstood to refer only to insecticides, the term pesticide also applies to herbicides, fungicides and various other substances used to control pests. Under United States law, a pesticide is also any substance or mixture of substances intended for use as a plant regulator, defoliant or desiccant.

Many household products are pesticides, including those listed below:

  • Cockroach sprays and baits

  • Insect repellents for personal use

  • Rat and other rodent poisons

  • Flea and tick sprays, powders and pet collars

  • Kitchen, laundry and bath disinfectants and sanitizers

  • Products that kill mold and mildew

  • Some lawn and garden products, such as weed killers

  • Some swimming pool chemicals

By their very nature, most pesticides create some risk of harm to humans, animals or the environment because they are designed to kill or otherwise adversely affect living organisms. At the same time, pesticides are useful to society because of their ability to kill potential disease-causing organisms and control insects, weeds and other pests. In the United States, the Office of Pesticide Programs of the Environmental Protection Agency is chiefly responsible for regulating pesticides. Biologically based pesticides, such as pheromones and microbial pesticides, are becoming increasingly popular and often are safer than traditional chemical pesticides.

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