By By Steve Strong / area horticulture extension agent
July 16, 2003
Outdoor work or play is always a challenge during a classic July heat wave, but the newest batch of insect invaders is making yard and garden activities nearly impossible.
Gnats are the most recent addition to the growing list of buggy pests this summer, and residents in East Mississippi are at their wit's end trying to find some kind of relief.
Mosquitoes are enough to worry about, carrying diseases like West Nile Virus and Eastern Equine Encephalitis.
But with skeeters, at least you have the option of repellent sprays and staying indoors during early morning or evening hours.
What makes gnats so pesky is that they are also active during broad daylight when a lot of folks are trying to work or recreate.
Gnats and midges (often called blind mosquitoes) are common names for a large number of small flies that flock together in swarms, attempting to get into your eyes, ears, nose, mouth or just about any orifice they can find.
They are apparently attracted to the mucous secreted by various animals, and they can be extremely annoying to both people and pets.
The one good thing about the nasty buggers is that at least they do not bite. Gnats make up for a lack biting ability, however, forming clouds around your head anytime you set foot on lawn turf or ball fields.
These critters are actually attracted to light, so wearing white or other lightly colored clothing (like you're supposed to in the heat of summer) probably just makes gnat attacks worse.
Like their mosquito cousins, gnats and midges are water-loving species that lay eggs in ponds, pools, clogged rain gutters, even in wet soil or seepage areas.
Mostly, they feed on living or decaying plant matter (they are vegetarians, thank God), and are an important part of aquatic food chains.
That bit of trivia leaves no room for sympathy, though, does it?
Sadly, control measures to fight gnats are limited, unless the area you are treating is quite small.
Products containing pyrethrins can kill gnats or other kinds of fly species, but they work only on contact (by directly hitting the insect), and there is little or no lasting residual effect from pyrethrin sprays. Treating turf areas where gnats live can give some temporary control, using insecticides such as malathion or carbaryl (Sevin).
Rainfall or irrigation water will quickly dilute the chemicals, and none of these pesticides should be used to treat pool or pond water. For water gardens or small, stagnant ponds, the larvacide known as Bt (short for a bacterium called Bacillus thuringiensis), can be safely applied to kill the immature life stages of gnats and other insects that breed in standing water.
The Bt products are sold under a variety of brand names such as mosquito briquettes, or dunks, and folks should follow the label directions carefully for application rates based on cubic feet of water.
To restate again, insecticide sprays or dusts should not be used to treat water, because the potential threat to wildlife and rest of the environment is too great to justify treatment of such a temporary nuisance.
For more information on common sense pest control, contact the county Extension office at 482-9764, or visit the Mississippi State University Web site at www.msucares.com.
When all else fails, and gnat attacks have you cornered, try covering your head with a piece of finely woven netting found at fabric stores or sporting good outlets. You may be a little hotter under the collar, but at least you can still breathe.