Menu
Published on 08/24/02

Control mosquito larvae in the water

By Nancy C. Hinkle
University of Georgia

The best and cheapest way to control mosquitoes is to prevent their larvae from developing.

Mosquito larvae can develop only in water, pupating while they're suspended from the surface. Getting rid of places where water collects, or making these places inhospitable to mosquito larvae, can keep you safer from mosquito-borne diseases.

Used tires are significant breeding sites. Tires should be recycled and properly disposed of to prevent their becoming mosquito sources. Tire dumps should be reported to county officials and removed so they don't become health hazards.

Around the yard

Around the yard, turn any vessel that holds water upside down, or remove and recycle it.

Clean out birdbaths weekly and replenish them with fresh water. This will keep mosquitoes from developing.

To control mosquito breeding, drain or flush the water weekly in wading pools, roof gutters, flowerpot saucers and other spots where rain and irrigation water collect.

Trim shrubbery and eliminate tall grass and weeds where adult mosquitoes hide during the day.

For personal protection

For personal protection:

  1. Wear light-colored clothing when outside, because dark colors attract mosquitoes.
  2. Stay indoors at dawn and dusk, when mosquitoes are usually most active.
  3. Wear a repellent containing DEET and treat clothing with a product such as Permanone mosquito repellent (containing permethrin). Herbal repellents work for less than 1 hour.
  4. If using citronella candles, orient them so that the breeze is directing the candle smoke toward you. The smoke is what repels mosquitoes.

What doesn't work

Mosquito plants don't repel mosquitoes. Neither do garlic, ultrasonic devices or herbal bracelets.

Traps that use light and/or carbon dioxide to lure in and kill mosquitoes may attract more mosquitoes than they kill. If you decide to use one of these, consider buying one and giving it to your neighbor down the street.

For severe infestations, an option is to hire a professional pest control company with expertise in mosquito control. Vector control personnel often treat breeding areas with a low-toxicity pesticide called Bti (Bacillus thuringiensis israelensis). It is deadly to mosquito larvae, yet harmless to people, pets, fish and wildlife.

You can't see in your rain gutters, so assume there are puddles trapped up there. Some of the mosquito larvicides listed below can be tossed onto roofs so they wash down into the gutters and control mosquito larvae there.

OTC larvicides

Over-the-counter mosquito larvicide products:

  • Agnique. The active ingredient forms a film on the water surface that smothers mosquito larvae. You can buy it from Adapco through a toll-free number (800-367-0659).
  • Altosid 30-Day Briquets. The active ingredient is methoprene, an insect growth regulator. You can buy it on-line.
  • Bactimos Briquets. The active ingredient is Bti, a bacterium specific to mosquitoes. It's a sustained-release, floating formulation.
  • Mosquito Dunks. The active ingredient is Bti. It's available at hardware, feed-and-seed and garden stores. Each dunk treats 100 square feet of water surface.
  • Mosquito Bits. These contain the same product as Mosquito Dunks, but in small amounts that can be used for smaller areas.
  • Zodiac Preventative Mosquito Control. The active ingredient is methoprene. It's available at pet stores.

Mosquito fish

Another biological control option is stocking standing water (ditches, ponds, lily pools, etc.) with mosquito fish (Gambusia).

These small minnows feed on mosquito larvae and reproduce so they maintain themselves and provide ongoing suppression. These tiny fish can be ordered on-line (for example, from Ken's Fish Farm, toll-free at 877-536-3474).

Mosquito fish can even be used to stock watering troughs. Pools formed by creeks that are no longer flowing are prime sites for using mosquito fish.

When using any insecticide, always read and follow label instructions to protect yourself and the environment. For more information, call your county Cooperative Extension office.

Nancy Hinkle is a Cooperative Extension entomologist with the University of Georgia College of Agricultural and Environmental Sciences.