Mosquitoes in San Antonio: Species, West Nile and Yard Control
Most mosquitoes biting you at home were born very close by, in water that sat still for about a week: a plant saucer, a clogged gutter, a tire or a birdbath. Dumping and covering standing water every week is the single most useful step, and a professional treatment of breeding and resting spots can lower numbers further. No treatment is permanent, because new mosquitoes hatch every time water collects again.
To have a technician look over your yard, call or text (210) 281-1064 or book online.
Which mosquitoes bite around San Antonio? #
Texas A&M AgriLife has identified 85 mosquito species in Texas. Around homes, two groups cause most of the trouble:
- Southern house mosquito. A plain, dull-brown mosquito with no bands on its legs. It bites in the evening, at night and in early morning, slips in through unscreened windows and doors and prefers birds as hosts. It is the main carrier of West Nile virus in Texas. It rarely flies more than a mile from where it hatched.
- Asian tiger mosquito. Black with bright white stripes on its legs and a white stripe down its head and back, averaging about 6 mm. It bites during the day, especially in shade, and lays eggs on the inside walls of containers and in tree holes.
- Yellow fever mosquito. A close relative of the tiger mosquito that prefers to bite people and lives both indoors and out.
A quick clue: bites in the shade in the afternoon usually point to the striped container breeders. Bites after sunset usually point to the brown house mosquito.
Where do mosquitoes breed in your yard? #
All mosquitoes need water to grow. Eggs hatch into larvae and then pupae that live in the water before adults emerge. For the striped container mosquitoes, the whole cycle from egg to adult takes 7 to 10 days, according to the CDC, and their eggs can survive drying out for up to 8 months while stuck to a container wall. The next rain brings them back to life.
These mosquitoes don't travel far. CDC says they fly only a few blocks in their lifetime, and AgriLife puts the range at 200 to 300 yards from where they bred. That means the source is usually on your property or a neighbor's. Common spots:
- Flowerpot saucers, buckets, planters and toys
- Clogged gutters
- Birdbaths and trash containers
- Old tires
- Tree holes, rain barrels without mesh and open vent or plumbing pipes
- Neglected pools (AgriLife says a maintained pool usually isn't a problem)
AgriLife also notes that after a heavy rain, floodwater mosquitoes appear first, then the container breeders, then the house mosquitoes that favor stagnant water rich in bacteria. Between breeding trips, adults rest in dark, damp places such as under patio furniture, in carports and garages and in shady shrubs.
When is mosquito season in South Central Texas? #
The City of San Antonio's Metro Health mosquito program runs its surveillance from March through October. In the Hill Country, Kendall County Environmental Health submits mosquitoes for the state's arbovirus testing program from May through November. DSHS notes mosquitoes stay active into November and December in much of Texas, so a warm fall can stretch the season.
Are mosquitoes dangerous? #
Only female mosquitoes bite; they need the blood to make eggs. A typical bite turns into a puffy red bump within minutes and a hard, itchy bump a day later. CDC says a large area of swelling, hives or a low fever can signal a stronger reaction.
West Nile virus is the main disease concern. The CDC says it is the leading mosquito-borne disease in the continental U.S. About 80% of infected people never feel sick, about 20% get a fever and other symptoms, and fewer than 1% develop a severe illness of the brain or nerves. Risk rises with age, and there is no vaccine for people. DSHS reported 455 Texas cases and 56 deaths in 2024. Get medical care right away for a high fever with a stiff neck, confusion, muscle weakness or tremors.
Health departments in Texas also keep watch on the striped container mosquitoes, because they can carry dengue, Zika and chikungunya.
Pets face their own risk. The FDA says heartworm spreads only through mosquito bites, and preventives require a veterinarian's prescription.
What can you do about mosquitoes yourself? #
Once a week:
- Empty and scrub, turn over or cover anything that holds water.
- Clear gutters and fill tree holes.
- Cover rain barrels tightly or with fine mesh.
- Check again after every good rain.
Every day:
- Use an EPA-registered repellent and follow the label, including its limits for young children.
- Wear loose long sleeves and pants outdoors, especially at dawn and dusk.
- Keep window and door screens repaired.
What doesn't work #
- Bug zappers. AgriLife says they mostly kill beneficial insects, not the female mosquitoes that bite.
- Sonic repellers. An AgriLife entomologist said bluntly that they don't work.
- Propane carbon dioxide traps. They can draw in more mosquitoes than they catch.
- Citronella candles. A light breeze carries the scent away.
How do professionals reduce mosquitoes? #
The EPA describes integrated mosquito management: watching where mosquitoes are, removing breeding water, treating larvae in water that can't be dumped, treating adults where they rest and teaching residents what to do. AgriLife's backyard guide, ENTO-054, covers the same tools for a home yard:
- Larvicides in water you can't drain kill larvae before they become biters. Some last up to about 30 days and others longer, so they need reapplying through the season.
- Residual treatments on resting sites like house walls, doorways, shrubs and trees can suppress adults for up to a month. AgriLife notes a typical homeowner spray lasts only 24 to 48 hours.
- Fogging gives relief for a few hours to overnight, which can help before an outdoor event.
AgriLife urges spraying in the evening, keeping sprays off blooming plants because they can harm bees, and avoiding overuse, which breeds resistance. EPA notes that many adult mosquito products are toxic to fish and bees, so label directions matter.
Will the city spray my yard? #
No. Metro Health handles mosquito control on public property inside San Antonio city limits and does not treat private yards for mosquitoes. When it finds West Nile in a trap, it may fog the area and run prevention outreach. For mosquito questions, the city lists 3-1-1 or 210-207-6000.
How does Pest Trappers handle mosquitoes? #
We help with mosquitoes at homes and businesses in San Antonio, Boerne, New Braunfels, Schertz and Cibolo.
- Yard inspection. The technician walks the property looking for breeding water and the shady places adults rest, and points out what you can dump, cover or fix.
- Options. You'll hear the treatment options that fit your yard, how long each tends to last and how to protect bees, fish and pets.
- Label rules. Products are applied exactly as their labels direct. The work is done under Pest Trappers LLC (TPCL #0887549), a family-owned San Antonio company.
Pricing is quoted after the inspection. Book online or call or text (210) 281-1064, and the office will confirm your time. Se habla español. If ticks are also a problem in the yard, see our tick guide.