TL;DR
- San Diego County Vector Control says invasive Aedes mosquitoes were first found in the county in 2014. They bite during the day, can bite more than once, and lay eggs in small containers of water. Even 1/4 inch of water is enough.
- The CDPH Aedes detection table, updated May 1, 2026, lists Aedes aegypti as Present in its named San Diego County communities. It lists Aedes albopictus as Not Found in those current community entries.
- County Vector Control reported San Diego County’s first locally acquired dengue case in 2025. Most dengue cases here remain travel-related.
- Effective control still has three jobs: dump standing water, treat water that cannot be dumped (Bti or mosquitofish where the label and county program allow), and ask a licensed applicator about adult resting habitat rather than treating a broadcast lawn spray as the whole plan.
San Diego County’s mosquito problem changed after invasive Aedes arrived. Before then, native Culex species that bite at dusk and can transmit West Nile virus were the main public-health mosquito story. Aedes mosquitoes use small backyard containers, bite during the day, and are competent vectors for several viruses. This post stays with what San Diego County Vector Control, the California Department of Public Health, CDC, EPA, and UC Statewide IPM actually publish. It does not invent ZIP totals, inspection counts, or a Pest Pros monthly protocol.
For thorax marks that separate Aedes aegypti from Aedes albopictus, use Asian tiger or yellow fever mosquito: how to tell. Neighborhood and bite time are not identification.
Where this data comes from
Every statistic referenced in this post traces to one of these primary sources. We link directly to each so you can verify and dig further:
- San Diego County Department of Environmental Health & Quality, Vector Control, invasive Aedes, first county detection year, container breeding, bite timing, mosquitofish, and the 2025 locally acquired dengue note.
- California Department of Public Health, Aedes detections by county and city, updated May 1, 2026 in the captured table.
- CDC, mosquitoes, mosquito-borne disease prevention framing.
- UC Statewide Integrated Pest Management, mosquitoes, container source reduction and Bti for larvae.
- EPA, Bti for mosquito control, what Bti targets and what EPA says about human and honey bee risk.
We do not cite aggregator sites or unpublished dashboards.
How does Aedes establishment in San Diego compare to other California counties?
Read the current CDPH table, not a summary invented here. As of the May 1, 2026 update, San Diego County community rows in that table list Aedes aegypti as Present and Aedes albopictus as Not Found. UC IPM notes that California was invaded by Aedes aegypti and Aedes albopictus in 2011 and 2013 as a statewide history. That statewide arrival note is not the same as treating both species as currently present in every San Diego community.
County Vector Control’s current Aedes page describes invasive Aedes as small black-and-white striped mosquitoes that bite during the day, especially around the legs and ankles, can bite aggressively and multiple times, are most active in San Diego during summer and fall, and breed indoors and outdoors in small containers. When it is warm, they can go from egg to adult in less than one week. Eggs can survive for months in dry containers and hatch when water is added.
Native Culex mosquitoes and invasive Aedes do not use the same homeowner checklist. Aedes work is container-scale. Dumping a saucer matters more than treating a pond as the only source.
Where in San Diego County is Aedes pressure densest?
County Vector Control publishes a map of where invasive Aedes have been found recently. It does not publish a ZIP-code density ranking in the captured Aedes page, so this article does not invent one. CDPH lists named communities with Aedes aegypti Present. That is presence, not a ranking of bite pressure.
What the county does say for homeowners: if you are getting bitten, the mosquitoes are probably coming from somewhere close by. Dump standing water inside and outside at least once a week. Check buckets, birdbaths, potted-plant saucers, and children’s toys. Talk to neighbors after you dump your own water.
| Factor the agencies actually name | Why it matters |
|---|---|
| Small containers | County: even 1/4 inch of water is enough for invasive Aedes eggs. |
| Eggs that survive dry periods | County: eggs can survive for months, then hatch when water is added. |
| Neighboring yards | County: work together after you dump your own sources. |
| Screens | County: use fine mesh so small Aedes cannot get indoors. |
An individual yard treatment can miss the next generation if containers remain. That is source reduction, not a promise that one spray ends bites.
What diseases can Aedes transmit, and what’s been documented in San Diego?
County Vector Control states that Aedes aegypti and Aedes albopictus can spread Zika, dengue, yellow fever, and chikungunya. It also notes Aedes notoscriptus has been found in the county and can spread diseases including dog heartworm.
On dengue specifically, the county says diseases like dengue that are spread by Aedes are rare in San Diego but more common in many places around the world. Most dengue cases in San Diego County are due to travelers returning from other parts of the world. In 2025, San Diego saw its first case of locally acquired dengue, meaning the person was infected in San Diego without traveling.
CDC’s mosquito overview treats dengue, West Nile, and malaria as examples of mosquito-borne disease and tells people to prevent bites. It does not, in the captured about page, publish a San Diego case table. This article does not invent Zika, chikungunya, or yellow fever case counts for the county.
CDPH publishes its own vector-borne disease materials separately from the Aedes detection table. Use those agency pages for current case numbers. Do not treat this blog as a surveillance bulletin.
How do homeowner control strategies have to change?
UC IPM and County Vector Control both put larval source reduction first. The three jobs below are that public guidance, not a Pest Pros service menu.
1. Source reduction (the most effective control)
County Vector Control: dump standing water. Invasive Aedes lay eggs in small containers, often in the backyard. Even 1/4 inch of water is enough. Dump inside and outside at least once a week.
UC IPM: empty water from unused garden pots and other objects. Store containers upside down, cover, or dispose of them. Even soda cans, jars, flower-pot saucers, or tree holes can support larvae. Rain barrels need screens or sealed fittings, or a labeled Bti product where screens are impractical.
This page does not invent how many sources a 30-minute audit will find.
2. Larvicide for water that cannot be eliminated
County Vector Control: if you cannot dump the water, you can add mosquitofish to backyard ponds, fountains, and unmaintained green pools. They are available free of charge from the Vector Control Program. You can also use a mosquito larvicide purchased at home and garden stores and follow the label.
UC IPM lists Bacillus thuringiensis subspecies israelensis (Bti) as a bacterium that kills mosquito larvae and does not affect people, other animals, or plants in the language of that pest note. EPA describes Bti as a soil bacterium whose toxins specifically target larvae of mosquitoes, black flies, and fungus gnats; EPA has concluded Bti does not pose a risk to humans, and studies indicate minimal toxicity to honey bees. Follow the current product label, including any drinking-water limits.
UC IPM and EPA describe Bti as a product that kills mosquito larvae. Adult knockdown is a different job.
3. Adult-mosquito treatment in resting habitat
Adult work is not a substitute for dumping water. If you hire a licensed company, ask where they will treat, which labeled product they propose, and how they will avoid flowering plants. Do not treat a monthly lawn spray quote as proof that breeding containers were handled. Pest Pros San Diego does not apply pesticides. The company you are matched with inspects first and quotes in writing.
Are foggers, citronella candles, and ultrasonic devices effective?
County Vector Control’s Aedes page points homeowners to EPA-registered, CDC-recommended repellents (DEET, picaridin, oil of lemon eucalyptus, IR3535, PMD, 2-undecanone), long sleeves and pants, and screens. EPA’s Bti page also lists standing-water elimination, screens, and EPA-registered repellents as measures besides spraying.
This article does not grade citronella candles, ultrasonic devices, or bug zappers. Those product classes are not evaluated on the captured county Aedes or EPA Bti pages. If a device has no EPA registration for mosquitoes, do not treat it as a yard-control plan.
What does this mean for picking a pest control program?
Ask any written mosquito proposal:
- Does this include a standing-water audit, or only adult spraying?
- What larvicide, if any, will be applied, and where? Is it a labeled Bti product?
- What is the plan for shaded resting habitat versus open lawn?
- How will pollinators be handled around flowering plants?
- What SPCB license branch does the company hold for this work?
There is no Pest Pros monthly mosquito protocol. Recurring service, if any, is the matched company’s written scope. See mosquito control for how matching works, or the pest control calculator for a planning worksheet. Neither is a treatment.
Frequently asked questions
How do I know if the mosquitoes biting me are Aedes?
Daytime bites in a backyard match how County Vector Control describes invasive Aedes activity. That is not a species identification. Native Culex species are still part of the county’s mosquito fauna, especially around dusk. Visually, county language is small black-and-white striped mosquitoes. CDPH currently lists Aedes aegypti as Present and Aedes albopictus as Not Found in the San Diego community rows of the May 1, 2026 table. See the ID comparison for a dedicated identification page.
Should I report Aedes mosquito sightings to San Diego County Vector Control?
County Vector Control publishes report links for mosquito breeding, green pools, and dead birds, plus requests for mosquito inspection and mosquitofish. Use those county forms. Free mosquitofish are a county program for ponds, fountains, and unmaintained green pools, not a Pest Pros offer.
Are mosquito control treatments safe for bees and butterflies?
EPA states Bti toxins specifically affect larvae of mosquitoes, black flies, and fungus gnats and that studies indicate minimal toxicity to honey bees. Adulticide sprays onto flowering plants are a different product class. Ask the licensed applicator which product, which sites, and how they will keep applications off forage.
Why does my yard get bitten worse than my neighbor’s?
County Vector Control: if you are getting bitten, the mosquitoes are probably coming from somewhere close by. Start with containers on your property, then talk with neighbors. This page does not rank yards.
Will mosquito pressure get worse in San Diego over time?
This article does not publish a forecast. Use current CDPH detection rows and the county Aedes map. Climate projections that are not on those pages stay off this page.
Methodology note
This post summarizes information from the primary sources cited above as captured for this repair. Specific figures (2014 first county find, 1/4 inch of water, May 1, 2026 CDPH Present / Not Found rows, 2025 first locally acquired dengue) are reported from those pages without adding ZIP totals or invented case counts.
We do not publish original Aedes surveillance data. That is San Diego County Vector Control’s job. If you need primary surveillance data, work from the county and CDPH sources linked above.
Pest Pros San Diego matches San Diego County customers with licensed local companies. Call (858) 400-6561 to get matched with a licensed local pro.
This article was reviewed for technical accuracy against the primary sources cited above. Updates to vector-borne disease surveillance, pesticide registration, or county-level Aedes distribution data may supersede specific points in this article. Verify against the linked primary sources for current information.