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Pests and pest control in California

Pests to know in California

Why each one matters here is cited in the sections below.

Pests documented in California

From public GBIF occurrence records since 1990. A record means a species was documented in California, not that it's common near you.

Many public records (812)

Fewer public records (109)

Range named by extension sources (22)

Termites in California

  • California has at least 23 termite species, and pest species there include subterranean, drywood, and dampwood termites.[2]
  • Subterranean termites are common throughout California, while drywood termites are most prevalent in Southern California, including desert areas, and also occur along most of the coast and in the Central Valley.[2]

Invasive species reported here

  • The Formosan subterranean termite, native to China, is established in California but so far only in a small area near San Diego.[2]
  • Two invasive mosquitoes, Aedes aegypti (yellow fever mosquito) and Aedes albopictus (Asian tiger mosquito), have become established in many parts of California, especially Southern California and the Central Valley.[3]

Pests local experts flag

  • The Argentine ant is the most common ant in and around homes and gardens in California.[4]
  • California has two widow spiders: the western black widow, found in populated areas almost everywhere in the state, and the non-native brown widow, which became established in Southern California in the 2000s.[5]
  • In California, Lyme disease is spread by the western blacklegged tick, and the state health department says risk is highest from spring through fall.[6]

Public agencies that handle pests

The California Department of Public Health's West Nile virus website tracks the virus statewide and asks residents to report dead birds, one way of tracking where the virus may be spreading.[7]

Hiring a licensed company

California's pesticide regulatory agency is the California Environmental Protection Agency (Department of Pesticide Regulation).[1]

Licensing agency: California Environmental Protection Agency — Department of Pesticide Regulation[1].

See also how to check a pest control license.

Free local help

The University of California Statewide IPM Program offers an online tool for identifying more than 650 plant pests, diseases, and abiotic problems.[8]

Local guides in California

Through the year

Spring to Fall
In California, native Reticulitermes subterranean termites swarm on clear spring or fall afternoons after a soaking rain, while the desert subterranean termite flies in July, August, and September.[2]

Sources

  1. National Pesticide Information Center, “State Pesticide Regulatory Agencies.” npic.orst.edu/reg/state_agencies.html (accessed 2026-10-06)
  2. UC Statewide IPM Program (University of California Agriculture and Natural Resources), “Pest Notes: Subterranean and Other Termites.” ipm.ucanr.edu/home-and-landscape/subterranean-and-other-termites/ (accessed 2026-10-06)
  3. California Department of Public Health, “Aedes aegypti and Aedes albopictus Mosquitoes.” www.cdph.ca.gov/Programs/CID/DCDC/Pages/Aedes-aegypti-and-Aedes-albopictus-mosquitoes.aspx (accessed 2026-10-06)
  4. UC Statewide IPM Program (University of California Agriculture and Natural Resources), “Pest Notes: Ants.” ipm.ucanr.edu/home-and-landscape/ants/ (accessed 2026-10-06)
  5. UC Statewide IPM Program (University of California Agriculture and Natural Resources), “Pest Notes: Widow Spiders and Their Relatives.” ipm.ucanr.edu/home-and-landscape/widow-spiders-and-their-relatives/ (accessed 2026-10-06)
  6. California Department of Public Health, “Lyme Disease.” www.cdph.ca.gov/Programs/CID/DCDC/Pages/LymeDisease.aspx (accessed 2026-10-06)
  7. California Department of Public Health, “California West Nile Virus Website.” westnile.ca.gov/ (accessed 2026-10-06)
  8. UC Statewide IPM Program (University of California Agriculture and Natural Resources), “Home and Landscape.” ipm.ucanr.edu/home-and-landscape/ (accessed 2026-10-06)

Updated 2026-10-06. Every statement on this page comes from the cited state, federal or university source. Spot an error? Tell us.