Mosquito Prevention & Information

The Vector Borne Illness Prevention Program monitors and works to reduce the mosquito population in Alexandria. We do this to help decrease the incidence of mosquito-borne illnesses. Learn more about mosquitoes, our program and what steps you can take to protect yourself and your family.

Page updated on Sep 13, 2016 at 8:31 AM

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Mosquito Prevention Tips

To get rid of adult mosquitoes around your home, follow these tips.

Once a week

  • Empty water and scrub containers, such as flowerpot saucers, watering cans, and buckets
  • Empty water and scrub bird baths before refilling
  • Empty water that collects in the folds of tarps used to cover woodpiles, boats, pools, etc.
  • Position corrugated drainpipes to ensure drainage (also see "once a month" recommendations below)

Once a month

  • Apply a larvicide (an insecticide applied to water to kill mosquito larvae), such as Mosquito Dunks®, to standing water that cannot be emptied or drained.

As necessary

  • Use screens on windows and doors. Repair holes in screens to keep mosquitoes outside. 
  • Clean leaves and debris from roof gutters.
  • Recycle old tires
  • Be sure water on property flows freely from drainage areas
  • Fill-in puddles or areas of your yard that remain wet and soggy for more than a week
  • Aerate ornamental ponds or stock the pond with fish
  • Apply a barrier spray to vegetation around your home. Products containing the active ingredient permethrin will provide two to three weeks of relief from biting adult mosquitoes. Always follow label instructions.
  • Applying Pesticides Correctly

Flowerpot Dish Collecting Water
Flowerpot Dish Collecting Water
Bird Bath Collecting Water
Bird Bath Collecting Water
Corrugated Drain Pipe Collecting Water
Corrugated Drain Pipe Collecting Water
Clogged Gutter Collecting Water
Clogged Gutter Collecting Water

Personal Protection 

To prevent mosquito bites:

  • Wear long, loose, and light-colored clothing
  • Choose and use a repellent that contains one of these active ingredients: DEET, Picaridin, oil of lemon eucalyptus, or IR-3535.

Different Types of Repellent

The best repellent is one that you will actually use.

  • DEET-based repellents are available in various concentrations that repel insects equally well for the length of time needed. DEET has provided effective, dependable protection since the 1950s. DEET is the most effective and best-studied repellent available.
  • Picardin is a synthetic repellent developed in the 1990s. It is colorless, nearly odorless, and is available in multiple formulations. It provides long-lasting, effective protection similar to identical concentrations of DEET. 
  • IR-3535 (Merck 3535) is registered as a biopesticide. Approved for use in the USA in 1999, it has been used in Europe for 20 years.
  • Oil of Lemon Eucalyptus is a natural plant-based repellent. Products containing oil of lemon eucalyptus provide protection similar to low concentrations of DEET. Products containing oil of lemon eucalyptus should not to be used on children under the age of three years.

All of these products are available in a wide variety of forms including aerosol and pump sprays, and wipes.

Precautions when Using Insect Repellents

  • Apply repellent only to exposed skin or clothing and always as directed on the label.
  • Do not apply repellents over cuts, wounds or irritated skin.
  • When using sprays, do not spray onto face – spray on hands first and apply from hand to face.
  • To avoid exposure to eyes or ingestion: children should not handle repellent; wash hands after application of repellent

Always follow label directions. Most repellents can be used on children >2 months; infants <2 months should be protected by keeping them indoors or using mosquito netting over their infant carrier when outdoors. Products containing Oil of Lemon Eucalyptus should not be used on children <3 years. Other than the safety tips above, the Environmental Protection Agency does not recommend any additional precautions for repellent use by pregnant or nursing women.

For more information on mosquito repellents visit:

Mosquito Identification

Asian Tiger Mosquito. Sean McCann. Copywrite 2006. The Asian Tiger Mosquito (Aedes albopictus) is the number one nuisance species found in the city. It is a black mosquito with striking white markings on its body and legs. The Asian Tiger Mosquito is a very aggressive mosquito that bites during the day. They prefer to bite people, and they lay their eggs in containers like tires, buckets, flowerpots, and corrugated drainpipes that hold water for five or more days. They live where it is cool, humid and shady, and do not travel far from there. Bushes like ivy and azaleas are their favorite resting places. The Asian Tiger Mosquito can spread West Nile virus, but it is unlikely.

Culex Species MosquitoCulex mosquitoes (Culex pipiens and Culex restuans) are small brown mosquitoes that bite during dusk and dawn. They prefer to bite birds, but they will bite people and other mammals. Because they are not as aggressive as other mosquitoes, you may not notice when one is biting you – a good reason to wear insect repellent! Culex mosquitoes lay eggs in stagnant, organic, nutrient-rich water. These are places like storm drains, clogged rain gutters and sites where water stands for a longer period of time (a few weeks). It is these mosquitoes that are most likely to spread West Nile virus

Mosquito Life Cycle

Mosquito Biology

There are four stages in the life of a mosquito: egg, larva, pupa, and adult. Mosquitoes need standing water to complete their life cycle.

  1. Mosquito eggs are laid so they hatch in water, generally not in moving water or water with aquatic life (fish, frogs)
  2. Larvae feed and grow in the water for about one week
  3. A larva turns into a pupa, which is also found in the water, but does not feed
  4. Inside the pupal case, an adult mosquito develops and transforms into the familiar flying form

Female mosquitoes bite because they need blood to develop their eggs. During the month a female mosquito is alive, she can lay eggs three or four times. Each time she lays eggs, she will lay up to 200-300 eggs.

What the City Does

The Vector Borne Illness Prevention Program is involved in a number of activities throughout the mosquito season and is responsible for:

  • Trapping adult mosquitoes to monitor mosquito populations
  • Testing the mosquitoes for West Nile virus to estimate the risk of mosquito-borne disease transmission
  • Responding to areas identified as having a higher-risk of disease transmission with increased surveillance, larvicide treatments, and/or community outreach
  • Proactively inspecting and larviciding storm drains. These areas are then recorded and mapped and are regularly treated to kill mosquito larva. We work with the City Transportation & Environmental Services to coordinate proper timing of larvicide applications around storm drain maintenance
  • Providing residents and businesses assistance with mosquito problems
  • Educating residents and businesses about mosquito control by periodically flyering various locations in Alexandria
  • Providing education and information at various local events and festivals to promote effective mosquito control
  • Giving presentations for various civic associations and communities
  • Investigating complaints about mosquitoes made by local residents

Staff checking for mosquitos in storm drain Staff applying pesticide Staff working in lab

Choosing a Pest Management Company

Some residents and businesses hire licensed, private companies to prevent and control pests and mosquitoes. Choose a pest management company that is licensed by the state. A list of licensed, private and commercial certified applicators can be found at Virginia Department of Agriculture and Consumer Services – Certified Applicators.

Other factors to consider when choosing a pest management company include:

  • The proposed work should follow the steps of Integrated Pest Management (IPM), not just pesticide application. IPM is an environmentally friendly, common sense approach to controlling pests. Go to EPA - Integrated Pest Management for more information.
  • Choose a company based on their quality of service, not the price. Get several proposals for service if possible and compare them.
  • Your pest management company should have a staff entomologist or access to one and the technicians should have experience with IPM and mosquito control.

For questions about pesticide spraying and pesticide products, contact the  Virginia Department of Agriculture and Consumer Services. Its Office of Pesticide Services, at 804.371.6560, has pesticide experts who investigate allegations of pesticide misuse.


Contact Us

Vector-Borne Illness Prevention Program
Alexandria Health Department
4480 King Street, 3rd Floor, Alexandria, VA 22302
703.746.4910 - Hours: 8 a.m. to 4:30 p.m. (M,Tu,W,F) and 1:30 to 4:30 p.m. (Th)

Questions or concerns?

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