Mosquitoes Around the Home: Species, Breeding Sites and Control

The mosquitoes biting you at home usually belong to one of three groups: Aedes, Culex or Anopheles. Many of them develop in standing water within a short flight of your yard, often in containers such as buckets, plant saucers, tires, toys and clogged gutters. Emptying those containers every week is the most effective thing a homeowner can do, and an EPA-registered repellent handles the rest.

Mosquitoes are true flies (order Diptera, family Culicidae). Only females bite; they need a blood meal to produce eggs. Males feed on nectar and other plant sugars.

How to identify a mosquito

Mosquitoes are small, slender flies with long legs, scales on their wings, and a long, needle-like beak (proboscis) that females use to pierce skin. Males have feathery antennae.

Several harmless insects get mistaken for mosquitoes:

• Crane flies look like giant mosquitoes with very long, fragile legs. They do not bite.
• Non-biting midges often swarm near water and do not bite.
• Fungus gnats are tiny dark flies around houseplants. See our flies page.

Mosquito species around US homes

Many mosquito species occur in the US, but three groups matter most around homes.

Aedes aegypti (yellow fever mosquito)

Aedes aegypti is a small, dark mosquito with white markings. CDC notes that it lives in tropical, subtropical and some temperate climates, which in the US means mainly southern states.

It is closely tied to people. CDC notes that it prefers to live near and bite people, both indoors and outdoors, and it lays eggs in water-holding containers such as buckets, bowls, pet dishes, flowerpots and vases. CDC identifies it as the main mosquito that spreads dengue, Zika and chikungunya viruses.

Aedes albopictus (Asian tiger mosquito)

The Asian tiger mosquito is black with white bands on the legs and a single white stripe running down the head and thorax. Ohio State University Extension reports it was introduced to the US in 1985, probably in imported used tires. CDC notes it tolerates a broader temperature range than Aedes aegypti, including cooler temperate climates.

It bites during the day, mostly from early morning through late afternoon, and prefers shade. It breeds in containers and tree holes, and Ohio State notes its larvae can develop in about half an ounce of water. Ohio State notes it does not usually fly far from where it developed, often less than 200 meters (about 650 feet).

Aedes eggs and behavior: Both Aedes species lay eggs on the inside walls of containers just above the waterline. The eggs stick firmly and can survive drying out for up to 8 months, according to CDC, hatching when rain or a sprinkler refills the container. That is why scrubbing containers matters, not only dumping them. Neither species usually travels more than a few blocks in its lifetime, so if you are being bitten during the day, the source is probably close.

Culex mosquitoes

Culex mosquitoes are most active from dusk to dawn and rest during the day in shrubs, grass and other cool, humid shelter. Some species prefer to feed on birds and bite people when other hosts are not nearby.

Females lay eggs in floating rafts of about 100 to 300 eggs on the surface of standing water. CDC lists their habitats as permanent standing water (ponds, swamps, neglected swimming pools), floodwater (storm drains, ditches, low pastures) and small containers around homes (buckets, tires, planters, toys, birdbaths and flowerpots).

In the US, Culex mosquitoes spread West Nile virus, St. Louis encephalitis virus and eastern equine encephalitis virus.

Anopheles mosquitoes

Anopheles females lay single eggs that float on the water surface, and the eggs die if they dry out, so these mosquitoes favor more permanent water such as marshes and the edges of shallow creeks and streams. They bite mostly in the evening and at night.

Anopheles is the group that spreads malaria. CDC notes that malaria is not endemic in the US: the roughly 2,000 cases reported in a typical year are almost all in travelers, and locally acquired cases are rare.

Mosquito life cycle

All mosquitoes go through complete metamorphosis with three stages in water:

1. Eggs are laid on or near water, singly, in rafts, or on container walls, depending on the group.
2. Larvae (“wigglers”) hatch, live in water, feed on organic particles and breathe at the surface. They molt four times.
3. Pupae (“tumblers”) are comma-shaped, do not feed, and transform into adults over one to two days.

CDC puts egg-to-adult development at about 7 to 10 days for Aedes and Culex, and about 10 to 14 days for Anopheles. In summer heat it can be a week or less. That timing is the reason for the weekly rule in the next section: water that sits for more than about a week can turn out a new batch of adults.

Breeding sites around the home

CDC’s advice is to empty and scrub, turn over, cover, or throw out anything that holds water once a week. Walk your property with this checklist:

• Buckets, watering cans and pails
• Flowerpot saucers and planters without drainage
• Birdbaths and pet water bowls (refresh at least weekly)
• Old tires, including tire swings
• Children’s toys, wading pools and sandbox covers
• Tarps and plastic covers that sag and hold water
• Clogged rain gutters and downspout extensions
• Trash and recycling bins, and their lids
• Boats, wheelbarrows and grill covers
• Rain barrels (cover openings with fine screen and check for leaks)
• Tree holes and stumps
• Corrugated drainpipes and low spots that hold rainwater
• Neglected swimming pools, hot tubs and their covers
• Ornamental ponds without fish or circulation
• Leaky outdoor faucets and air conditioner drip lines

A few extra steps for bigger sources:

• Water storage containers should have tight lids, or be covered with wire mesh with openings smaller than a mosquito.
• Septic tanks: repair cracks and gaps, and cover open vent pipes with fine mesh.
• Swimming pools: keep the water treated and circulating. Drain and turn over wading pools when not in use.
• Water you cannot drain (ponds, rain barrels, low areas) can be treated with a larvicide labeled for mosquitoes, such as products containing the bacterium Bacillus thuringiensis israelensis (Bti). Bti kills larvae that eat it and is very selective. Follow the label.

Indoors, change water in vases and empty plant saucers weekly too, since Aedes aegypti lives and lays eggs in and around homes.

Mosquito-borne diseases in the US

Most mosquito bites cause nothing worse than an itchy bump. But several viruses spread by mosquitoes do occur in the US, according to CDC:

• West Nile virus is the leading cause of mosquito-borne disease in the contiguous United States. It is spread mainly by Culex mosquitoes that become infected by feeding on birds. Most infected people have no symptoms, but CDC estimates that more than 1,300 people a year develop severe illness affecting the nervous system.
• Eastern equine encephalitis is rare, with only a few US cases a year, mostly in eastern and Gulf Coast states, but it is serious: about 30 percent of people with severe illness die.
• St. Louis encephalitis virus is spread by Culex mosquitoes in the US.
• La Crosse virus causes most of its cases in the upper Midwest, mid-Atlantic and Southeast. Severe illness is most common in children under 16.
• Dengue, Zika and chikungunya are spread mainly by Aedes aegypti and also by Aedes albopictus. CDC notes that recent US outbreaks of dengue and chikungunya have been relatively small and limited to small areas, with local outbreaks in parts of Florida, Texas and Hawaii and more transmission in territories such as Puerto Rico.
• Malaria is spread by Anopheles mosquitoes, but nearly all US cases are acquired abroad.

Mosquitoes also transmit dog heartworm, so talk to your veterinarian about prevention for pets.

If you become sick with a fever or other worrying symptoms after mosquito bites or travel, see a doctor and mention the bites.

Protecting yourself from bites

Use an EPA-registered repellent

CDC recommends repellents registered with the US Environmental Protection Agency (EPA), which reviews them for safety and effectiveness. Look for an EPA registration number on the label and one of these active ingredients:

• DEET
• Picaridin (called icaridin outside the US)
• IR3535
• Oil of lemon eucalyptus (OLE)
• Para-menthane-diol (PMD)
• 2-undecanone

The EPA also lists catnip oil and oil of citronella among registered skin-applied repellent ingredients. CDC advises against using products containing OLE or PMD on children under 3 years old. Read and follow the label, including any directions for use on children.

Dress for it

Wear loose, long-sleeved shirts and long pants when mosquitoes are active. Clothing and gear treated with permethrin stay protective through several washings. Permethrin is for fabric only and should never be applied to skin.

Keep them out of the house

Install and repair window and door screens, keep doors closed, and use air conditioning when you can.

University of California IPM notes that many popular gadgets do not work, including wristbands, ultrasonic devices, vitamin B1 and garlic. Bug zappers are counterproductive because they kill insects that prey on mosquitoes.

Yard measures and community programs

Source reduction is the foundation, and it works best when neighbors do it too. Beyond emptying containers:

• Drain temporary pools of water or fill low spots with soil.
• Clean gutters so they do not hold water.
• If you use an outdoor insecticide labeled for adult mosquitoes, CDC suggests treating places where adults rest, such as under patio furniture, carports and garages, and following the label. Insecticides are a supplement: CDC notes they will not keep a home mosquito-free on their own.

Many cities, counties and special districts run mosquito control programs. The EPA describes these programs as integrated pest management: they monitor mosquito populations and disease activity, reduce breeding sites, treat larvae in standing water such as storm drains and ditches, and apply adult mosquito control by truck or aircraft mainly during disease outbreaks or very heavy infestations. Some, such as California’s vector control districts, also supply mosquito-eating fish for ornamental ponds. Contact your local health department or mosquito control district to report problem sites, ask about services, or find out about spraying schedules.