Treatment of Mosquitoes

2023 Mosquito Control Program (runs through September 30)

The Maryland Department of Agriculture provides mosquito control services to the Bowie area. The mosquito control program begins in March with spring larviciding in March and will continue until September.

The program consists of larviciding (control of immature stages of the mosquito), public education about the Asian tiger mosquito, and adult surveillance with possible spraying.

Larviciding - Larviciding, proven the most effective treatment, means treating the immature stages (eggs, larvae or pupae) of the mosquitoes in the stagnant water where they occur. Known breeding areas in your community will be checked approximately every 3 weeks for the presence of larvae and will be treated if necessary. Three different products are used for larviciding.

  • Bti granules - This is a granular formulation of a bacterium, Bacillus thurinziensis var israelensis. These bacteria produce a substance toxic to mosquito and black fly larvae but not harmful to other organisms. The material is not persistent in the environment; the bacteria do not reproduce and multiply so the effect of the bacteria is very temporary.
  • Bacillius sphaericus granules – These bacteria also produce a substance toxic to mosquito larvae. Under certain conditions, they can recycle in the breeding area for up to 30 days.
  • Methoprene briquet, pellet, & granule - This substance is an insect growth regulator, causing incomplete development within the immature stages. The mosquito dies before becoming a biting adult. The briquet and pellet formulations last up to 30 days, slowly releasing the active ingredient into the breeding area. The granule lasts for several weeks.
  • Natular granules - This granular formulation of the spinosad bacterium is toxic to mosquito and midge larvae. It can remain effective for up to 30 days.

Larvaciding is generally more cost effective than treatment for adult mosquitoes because as larvae, the mosquitoes are concentrated in a few breeding areas. Once these larvae become adults, they disperse widely and larger areas must be treated.

Adulticiding – Communities are visited based on the Adult Mosquito Surveillance / Spraying Schedule if warranted, as resources allow.

A surveillance crew member will either place a portable light trap overnight or do a landing count in complaint areas. If the number of female mosquitoes does not exceed the action threshold (3 female mosquitos in a 2 minute count, 10 female mosquitos per night in an unbaited light trap or 24 female mosquitos per night in a baited light trap), spraying will not be done.

The reason for this surveillance is that the permethrin used for adult control is a contact insecticide; it must contact the mosquito to kill it. If spraying is determined to be necessary, the spray shift will run in the late evening to try to coincide with the time of peak mosquito activity. If the sprayer operator encounters too many people outside in the spray area, spraying will not be done. Therefore, please do not to stand around outside in your neighborhood while the spray trucks are coming through your areas.

An individual resident may have his/her owned or leased real property excluded from the adult mosquito control spraying. A resident wishing to exclude their property must submit a request directly to the Maryland Department of Agriculture. Information on excluding a property and the required submission forms are available on the Maryland Department of Agriculture website. The MDA Opt-Out Form is also in the Quick Links section on this page.

If an "unscheduled spray" takes place due to trapped mosquito with a positive test result for a mosquito-born illness, any and all exemptions will be temporarily suspended.

View the Adult Mosquito Surveillance / Spraying page.

Asian Tiger Mosquito
Since the Asian tiger mosquito has become a major problem in this area, we are trying to distribute information about this mosquito in an effort to reduce backyard breeding of this annoying mosquito pest.

Mosquitoes can breed in any water-holding container including bird baths, wading pools, pet watering dishes, tin cans, old tires, clogged gutters or flower pots. To prevent mosquito breeding in these areas, water should be changed weekly in bird baths, wading pools and pet dishes, gutters should be cleaned at least twice a year, and other water-holding containers should be disposed of or stored upside down.

If you choose to spray your yard for the Asian Tiger Mosquito, make sure to purchase the correct pesticide from a hardware store or a professional pest control agency. Be certain that what you choose is labeled for the treatment of mosquitoes. There are many different brand names that will work. Some of the active ingredients to look for on the label which work well against Asian Tigers are Resmethrin, Permethrin, and Pyrethrin. These are just suggestions, there are others that will work.

Adult Asian Tigers spend most of the time resting in bushes, ivy, tall grass, under decks, and in other shady, sheltered areas. Concentrate treatment in these areas. Although they are active all day, Asian Tigers seem to be most active around dusk. Therefore, this is the best time to treat.

If you need assistance reporting breeding areas around your house and would like to report stagnant water or drainage issues near your property, call the Public Works Office at 301-809-2344.

MD Department of Agriculture Mosquito Control website.