Mosquitoes in the San Gabriel Valley
The SGV's mosquito story changed when the daytime ankle-biters arrived. Here's what's biting, the standing water behind it, and the free help most residents don't know exists.
- Daytime biting around ankles = invasive Aedes mosquitoes
- Native Culex mosquitoes bite at dusk and night
- They breed in tiny amounts of standing water — a bottle cap is enough
- Itchy welts, often several in a cluster
- Peak season roughly April through October
What they look like
The mosquito picture in the San Gabriel Valley changed around a decade ago when invasive Aedes mosquitoes — small, black-and-white striped “ankle biters” — established here. Unlike our native Culex mosquitoes, which bite around dusk, Aedes bite aggressively during the day, usually low on the legs and ankles.
Both are more than a nuisance: Culex can carry West Nile virus, which is why mosquito control in California is taken seriously enough to have its own public agencies.
Mosquitoes fast facts
| Detail | |
|---|---|
| Looks like | Small; Aedes are black with white stripes |
| Where found | Anywhere with standing water nearby |
| What they do | Itchy bites; can carry disease |
| Active when | Aedes by day, Culex at dusk; Apr–Oct peak |
| Concern level | Real — bites plus disease potential |
Where they live
Mosquitoes don't travel far from where they hatch — invasive Aedes often stay within a couple hundred feet. If you're getting bitten in your yard, the breeding water is usually on your property or a neighbor's: plant saucers, buckets, clogged gutters, fountains that stopped running, trash-can lids, even a bottle cap. They need only a spoonful of water and about a week.
That's why fogging a yard rarely fixes anything for long — the source keeps producing new mosquitoes every few days.
Signs of a problem
Getting bitten during the day around the ankles and lower legs is the classic invasive-Aedes sign. Clusters of itchy welts after time in the yard, mosquitoes resting on shaded walls, and wrigglers (larvae) in any standing water are the others.
If bites happen mostly at dusk instead, that points to native Culex — same fix: find and dump the water.
How they are controlled
Honest answer first: routine mosquito abatement isn't an ExterMetro service — and in the San Gabriel Valley you already pay for a dedicated public agency that does it. The San Gabriel Valley Mosquito & Vector Control District responds to mosquito problems, inspects sources and treats them — free. Most residents have never heard of it, and it's the single most effective call you can make.
Your half of the job is water: walk the yard weekly and dump anything holding water, scrub saucers and buckets (Aedes eggs stick to the sides), keep gutters flowing and pools maintained. While we're treating your property for other pests, we'll point out breeding spots when we see them — and if what's actually biting you turns out to be fleas, that one is ours. Ask us anytime.
Related Pests
Quick Answers
Quick Answers.
Why am I getting mosquito bites during the day?
That's the calling card of invasive Aedes mosquitoes — the black-and-white 'ankle biters' established in the SGV over the last decade. They bite by day, usually low on the legs, and breed in tiny containers of water within a couple hundred feet of where they bite.
Does ExterMetro treat mosquitoes?
Routine mosquito abatement isn't one of our services — and honestly, you already have a better option: the San Gabriel Valley Mosquito & Vector Control District handles mosquito problems for residents free. We'll point out breeding water we spot during any service, and if the biting turns out to be fleas, that's our job.
What is the SGV Mosquito & Vector Control District?
A public agency, funded by property assessments, that inspects and treats mosquito sources across the San Gabriel Valley at no charge — including backyard problems and green pools. Requests go through sgvmosquito.org. It's the most effective mosquito call most residents never make.
How do I find where mosquitoes are breeding?
Walk the yard after watering or rain and look for anything holding water for a week or more: plant saucers, buckets, toys, clogged gutters, dead fountains, drain pans. Aedes need only a spoonful. Dump, scrub and flip — scrubbing matters because their eggs glue to container walls.
Are mosquitoes in the SGV actually dangerous?
They can be. Native Culex mosquitoes are the local West Nile virus carriers, and invasive Aedes are capable of spreading other viruses. Most bites are just itchy — but it's why mosquito control here has its own public agency, and why standing water is worth taking seriously.
Do bug zappers or citronella candles work?
Not meaningfully. Zappers mostly kill harmless insects, and citronella gives brief, localized easing at best. Finding and dumping the breeding water — and calling the district for what you can't reach — is what actually drops the numbers.
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