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Why We Use Pesticides

Pesticides are used to control various pests and disease carriers, such as mosquitoes, ticks, rats and mice. Pesticides are used in agriculture to control weeds, insect infestation and diseases.

There are many different types of pesticides; each is meant to be effective against specific pests. Some examples include:

  • Algaecides to kill and/or slowing the growth of algae.
  • Antimicrobials to control germs and microbes such as bacteria and viruses.
  • Disinfectants to control germs and microbes such as bacteria and viruses.
  • Fungicides to control fungal problems like molds, mildew, and rust.
  • Herbicides to kill or inhibit the growth of unwanted plants, also known as weeds.
  • Insecticides to control insects.
  • Insect Growth Regulators to disrupt the growth and reproduction of insects.
  • Rodenticides to kills rodents like mice, rats, and gophers.
  • Wood Preservatives to make wood resistant to insects, fungus and other pests.

Significant Public Health Problems that are Caused by Pests

Vector-Borne Diseases

Infectious diseases such as West Nile virus, Lyme disease, and rabies can be carried and spread by vector (disease-carrying) species such as mosquitoes, ticks, and rodents. EPA registers several pesticide products, including repellents, that may be used to control the vectors that spread these diseases. View information about transmission of the Zika virus in the United States and other locations.

Asthma and Allergies

Indoor household pests such as cockroaches can contribute to asthma and allergies. In addition to registering products to control these pests, EPA also provides information to the public about safely using these products in homes and schools.

Microbial Contamination

Various microorganisms, including bacteria, viruses, and protozoans, can cause microbial contamination in hospitals, public health clinics, and food processing facilities. EPA registers antimicrobial products intended to control these microorganisms and help prevent the spread of numerous diseases.

Avian Flu

Avian flu, sometimes called bird flu, is an infection that occurs naturally and chiefly in birds. Infections with these viruses can occur in humans, but the risk is generally low for most people. EPA works to register and make available antimicrobial pesticide products (sanitizers or disinfectants) that may be used to kill avian influenza virus on inanimate surfaces and to help prevent the spread of avian flu viruses. These products are typically used by the poultry industry to disinfect their facilities.


Certain proteins found in cells of the central nervous system of humans and animals may exist in abnormal, infectious forms called "prions." Prions share many characteristics of viruses, and may cause fatal diseases. In 2004, EPA determined that prions are considered to be a pest under FIFRA (PDF), and that products used to control prions are subject to EPA regulation.


Biological agents such as Bacillus anthracis spores can cause a threat to public health and national security. EPA has the authority to issue emergency exemptions for pesticides  for use in anthrax spore decontamination efforts.

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