EPA Definition of a Pesticide

What is a Pesticide?

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. Did you know that all of these common products are considered pesticides?

  • 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.

Here are some common kinds of pesticides and their function:

Algicides
Control algae in lakes, canals, swimming pools, water tanks, and other sites.
Antifouling agents
Kill or repel organisms that attach to underwater surfaces, such as boat bottoms.
Antimicrobials
Kill microorganisms (such as bacteria and viruses).
Attractants
Attract pests (for example, to lure an insect or rodent to a trap). (However, food is not onsidered a pesticide when used as an attractant.)
Biocides
Kill microorganisms.
Disinfectants and sanitizers
Kill or inactivate disease-producing microorganisms on inanimate objects.
Fungicides
Kill fungi (including blights, mildews, molds, and rusts).
Fumigants
Produce gas or vapor intended to destroy pests in buildings or soil.
Herbicides
Kill weeds and other plants that grow where they are not wanted.
Insecticides
Kill insects and other arthropods.
Miticides (also called acaricides)
Kill mites that feed on plants and animals.
Microbial pesticides
Microorganisms that kill, inhibit, or out compete pests, including insects or other microorganisms.
Molluscicides
Kill snails and slugs.
Nematicides
Kill nematodes (microscopic, worm-like organisms that feed on plant roots).
Ovicides
Kill eggs of insects and mites.
Pheromones
Biochemicals used to disrupt the mating behavior of insects.
Repellents
Repel pests, including insects (such as mosquitoes) and birds.
Rodenticides
Control mice and other rodents.

The term pesticide also includes these substances:

Defoliants
Cause leaves or other foliage to drop from a plant, usually to facilitate harvest.
Desiccants
Promote drying of living tissues, such as unwanted plant tops.
Insect growth regulators
Disrupt the molting, maturity from pupal stage to adult, or other life processes of insects.
Plant growth regulators
Substances (excluding fertilizers or other plant nutrients) that alter the expected growth, flowering, or reproduction rate of plants.

What about pest control devices? EPA also has a role in regulating devices used to control pests. More specifically, a "device" is any instrument or contrivance (other than a firearm) intended for trapping, destroying, repelling, or mitigating any pest. A mousetrap is an example of a device. Unlike pesticides, EPA does not require devices to be registered with the Agency. Devices are subject to certain labeling, packaging, record keeping, and import/export requirements, however.

What is not a pesticide? The U.S. definition of pesticides is quite broad, but it does have some exclusions:

  • Drugs used to control diseases of humans or animals (such as livestock and pets) are not considered pesticides; such drugs are regulated by the Food and Drug Administration.
  • Fertilizers, nutrients, and other substances used to promote plant survival and health are not considered plant growth regulators and thus are not pesticides.
  • Biological control agents, except for certain microorganisms, are exempted from regulation by EPA. (Biological control agents include beneficial predators such as birds or ladybugs that eat insect pests.)
  • Finally, EPA has also exempted certain other low-risk substances, such as cedar chips, garlic, and mint oil.

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