Mosquitofish help vanquish mosquitoes, disease in San Joaquin County

Mosquitofish wait to be delivered to their new homes as the San Joaquin County Mosquito and Vector Control District give away mosquitofish to residents in Lodi on Tuesday, June 23, 2015.

STOCKTON — As the weather warms up and the state of California kicks off its annual Mosquito Awareness Week, the San Joaquin County Mosquito & Vector Control District is calling on local residents to remove or treat any standing water on their property to prevent mosquitoes from laying their eggs.

Residents may also pick up mosquitofish from the district for any untreated water sources such as animal watering troughs, water features and ornamental ponds.

“Mosquito prevention is everyone’s responsibility, so dump and drain standing water and tip and toss containers,” district spokesman Aaron Devencenzi said in a press release.

Mosquitoes can carry a host of diseases, including West Nile virus and St. Louis encephalitis. Mosquitoes can also spread illnesses among animals, including West Nile virus among birds and horses and heartworm parasites in dogs and cats.

Last year, San Joaquin County had no human cases of West Nile virus. However, the county saw four equine cases in 2020. Four dead birds recovered and tested within the county were found to be carriers, and 260 mosquito samples tested positive for the virus.

Mosquitoes carrying St. Louis encephalitis were also identified in Lodi last August, and in November, San Joaquin County saw its first reported human case of the virus since 1973.

In addition to cleaning up standing water, the district offers the following tips for local residents to prevent mosquito bites and the spread of mosquito-borne illnesses:

  • Apply insect repellent containing EPA-registered active ingredients, including DEET, Picaridin, oil of lemon eucalyptus, or IR3535, according to label instructions, when outdoors. Repellents keep mosquitoes from biting.
  • Avoid spending time outside when mosquitoes are most active, at dawn and dusk, especially for the first two hours after sunset.
  • When outdoors, wear long pants, loose-fitting long-sleeved shirts, and other protective clothing when possible, especially during times mosquitoes are more active.
  • Keep mosquitoes out of your home with tight-fitting screens on doors and windows.
  • Contact your veterinarian for information about protecting pets from mosquito-borne parasites like heartworm, and vaccinate horses against West Nile virus and Western Equine encephalitis.

In 2019 and 2020, the district also identified invasive Aedes aegypti mosquitoes in the Brookside area of west Stockton. These mosquitoes are known to bite during daytime hours and can spread quickly, making them a nuisance. They can carry a host of diseases, including Zika, chikungunya, dengue and yellow fever.

Any mosquito infestations should be reported to the vector control district, as well as any daytime-biting mosquitoes.

For more information, to request mosquitofish, or to report an infestation, call 209-982-4675 or 800-300-4675, or visit

Residents are also asked to report any dead birds, which can help the district and the state track potential West Nile virus “hot spots.”

Recommended for you

comments powered by Disqus