Black Valley Gnat: base pests

  • Published
  • By 60th Civil Engineer Squadron
  • 60th Civil Engineer Squadron
TRAVIS AIR FORCE BASE, Calif. --  Team Travis has its share of insect challenges. The current pest problem involves the "no see um" insect called the Black Valley Gnat, which is a small biting fly that measures up to 1/16 of an inch (three to six millimeters) in length and is black in color in the adult stage. They are also known as buffalo gnats and by their more common name "no see-ums." The common name "no see-ums" comes from their size, they are so small they can enter your home by going through small holes in window screens. Their small size also makes it easy for them to crawl under loose fitting clothing. 

These gnats are normally active for four to eight weeks, beginning in mid-May and ending in July. Depending on the weather, they can be active for shorter or longer time periods. Adults normally start to appear when the soil starts to dry and crack. The larva of this insect is orange in color and found where they live in damp soil. They have also been reported living near water. The gnats have a life cycle lasting up to two years but have a hibernation cycle that can be three years or longer, depending on the environment. 

Perhaps the worst part about this insect is its bite. Only the female of the species bite because they feed on blood. The male gnats survive on honey dew or the nectar of flowering plants. These gnats bite humans, wild animals, livestock (horses and cows), pets and birds. When they bite, they inject saliva into the wound causing a small hemorrhage in the bitten area followed by severe itching. The symptoms appear 20 to 30 minutes after being bitten and the itching becomes severe after about 12 hours. 

Someone who is sensitive will notice a swollen itchy spot anywhere from one to two inches in diameter. Scratching the bites can increases the time it takes for them to disappear. If bitten, a person should find an anti-itching cream to gain some relief. If the itching last three to five days, consult a physician. These pests do not transmit any diseases or viruses to humans, wild animals, livestock, pets or birds. 

Currently there are no effective chemical control measures for this insect. Its larva can burrow up to 39 inches below the ground effectively protecting itself from any pesticides applied on or above ground. 

There are ways to protect against these gnats. The first is avoidance. Keep daytime outside activities to a minimum and avoid areas known to have a large population of these biting gnats. Their flight range is said to be about 350 feet, so stay at least 500 feet away from areas that have large populations. 

If in an infested area, wear a long sleeve shirt and pants. Tucking pants into the top of boots can keep them gnats from crawling under pant legs. 

Second, if going outdoors, consider using an insect repellent. Standard repellents used for mosquitoes will not provide much protection so look for N, N-Diethyl-meta-toluamide products for the skin and permethrin for use on clothes and uniforms. When looking for DEET products, try to find one in which the active ingredient is at least 20 percent or more DEET. For the permethrin products look for a percentage of active ingredient around .5 to 1 percent. Apply the permethrin to clothes and the DEET to the skin. The best protection is provided by using both of these products together. The DEET and permethrin will not keep the gnats from landing on you but should keep them from biting.

Some common repellents that have shown to provide at least some protection are Avon's Skin So Soft, Deep Woods Off, and Off's Skintastic. There are several other DEET and permethrin products you can use. To find one that works, you may need to do a little shopping. 

Third, keep your yard watered, unless we're in drought conditions. Watering will prevent the ground from cracking and keep the adults from finding their way to the surface during the mid-May time frame. Some experts believe this will also prevent the larva from burrowing deeper into the soil thus stopping the completion of its life cycle. 

Fourth, you can use an insecticidal aerosol labeled for flying insects. All you need to do is spray around the entrance ways and window screens. This will not keep them out of home, but will help minimize the population and keep them from entering home in such large numbers. If the insecticidal aerosol you are using leaves a residual, it will reduce the amount of gnats resting around window screens and entrance ways. 

If you have any concerns or questions contact the Pest Management Section by calling CE customer service at 424-2575.