COUNTY EXTENDING MOSQUITO SPRAYING IN LA MESA EARLY MON. AND TUES.
East County News ServicesJuly 11, 2025 (San Diego County) -- San Diego County officials plan to expand and extend ultra-low volume, truck-mounted, pesticide-mist treatments between 1 a.m. and 6 a.m. Monday and Tuesday mornings in parts of La Mesa to reduce mosquito populations and protect the public from the potential spread of West Nile virus.
County Vector Control announced this week that crews would conduct truck treatments through roughly 4,000 parcels in the community of Rolando, including parts of La Mesa and San Diego, between 1 a.m. and 6 a.m. Wednesday, Thursday and Friday.
Those treatments were done successfully Wednesday and Thursday and will continue Friday.
This weekend, Vector Control staff will be responding to emails at vector@sdcounty.ca.govand phone calls at (858) 694-2888 for questions from the community.
La Mesa city staff will also be available to answer questions at an information session from 10 a.m. until noon this Saturday, July 12 at the La Mesa Library, 8074 Allison Ave.
Treatments are now scheduled to be expanded into another 3,000 to 4,000 parcels in La Mesa after Vector Control detected more mosquitoes carrying West Nile virus. The new treatments will be done between 1 a.m. and 6 a.m. Monday, July 14 and Tuesday, July 15.
County Vector Control truck treatments will continue to use AquaDuet, a pesticide approved by the Environmental Protection Agency that poses low risks to people and pets.
The County reported June 27 that it had detected West Nile virus in mosquitoes collected in the Rolando area, and more in mosquitoes in follow-up surveillance, necessitating the pesticide spray treatments.
More information, including a map of the treatment area, frequently asked questions, and contact information for Vector Control, can be found on Vector Control’s Adult Mosquito Control Information webpage.
While the treatments pose a low risk to people and pets and the pesticide dissipates in roughly 20 to 30 minutes, residents may wish — as a precaution — to stay inside, keep pets and pet bowls inside, and close windows during the treatment.
Normal activities can be resumed 30 minutes after the treatment.
Beekeepers and those with insects kept outdoors are encouraged to shelter hives and habitats during treatments. Beekeepers registered with the County’s Department of Agriculture, Weights and Measures can request to receive advance notice when pesticide spraying that may affect bees is applied to blossoming plants in their areas.
There have been no reported human cases in San Diego County this year.
In 2024, the County reported 2 cases. However, West Nile virus remains a potentially deadly threat. Some people who become infected can suffer fever with other symptoms, headaches, body aches, joint pains, vomiting, diarrhea or rash.
in rare cases, West Nile virus can make people extremely ill and even kill them. If you have symptoms, seek medical care.
County officials said people should continue to follow the County’s “Prevent, Protect, Report” guidelines to protect themselves from mosquitoes. Those include finding and dumping out standing water around homes to keep mosquitoes from breeding.
Prevent mosquito breeding
Dump out or remove any item inside or outside of homes that can hold water — whether from rain or landscape irrigation. Those things can include plant saucers, rain barrels, buckets, garbage cans, toys, old tires and wheelbarrows.
Mosquitofish, available for free by contacting the Vector Control Program, may be used to control mosquito breeding in backyard water sources such as stagnant swimming pools, ponds, fountains and horse troughs.
Protect yourself from mosquito bites
Protect yourself from mosquito-borne illnesses by wearing long sleeves and pants or use insect repellent when outdoors. Use insect repellent that contains DEET, picaridin, oil of lemon eucalyptus, para-menthane-diol, 2-undecanone or IR3535.
Make sure screens on windows and doors are in good condition and secured to keep insects out.
Report possible mosquito activity and dead birds
Report increased mosquito activity, unmaintained green swimming pools, and other mosquito-breeding sources, as well as dead birds — including crows, ravens, jays, hawks and owls — to the County Vector Control Program by calling (858) 694-2888 or emailing vector@sdcounty.ca.gov
Go to San Diego County’s “Fight the Bite” website to learn how to prevent and protect against West Nile virus and mosquitoes.
For more information about West Nile virus, go to the County Health and Human Services Agency’s West Nile virus webpage.