MISSISSIPPI STATE -- What works in a spray bottle to control insects on tomato plants in the back yard also works to control cotton's No. 1 pest when sprayed from an airplane.

Malathion is a very common insecticide used by cities to control mosquitoes, gardeners to control vegetable pests, homeowners to control cockroaches, farmers to control boll weevils and pet owners to control pet pests. Even the concentration is similar for each of these applications.

Dr. Doug Gaydon, entomology specialist at Mississippi State University's Extension Service, said this chemical is perfectly safe when used as the label directs. About 30 percent of Mississippi cities and towns use Malathion to control mosquitoes.

"Treatment for mosquitoes usually runs from April to September with an average of three sprayings every two weeks," Gaydon said. "The machine goes through towns at 10 to 15 mph and sprays what amounts to 1 1/2 ounces per acre."

Malathion has been used for 20 or more years to effectively treat mosquitoes in towns, Gaydon said. Some towns have switched to other treatments because Malathion is so expensive, but it is as close to a mosquito-specific insecticide as exists.

"The mosquitoes are small and active at night, so we fill the air with billions of very tiny droplets of spray," Gaydon said. "Only the insects flying at night will bump into these and are killed, and mosquitoes are basically the only small insects flying after dark."

The insecticide works when a sufficient amount collects on the body of the insect. Large insects such as moths and butterflies are not affected by the spray as the droplets are too small to harm them, Gaydon said.

Billy Copeland, street foreman for Philadelphia, said this town has controlled mosquitoes for many years with Malathion.

"We usually start spraying about the middle of May and spray until about the first of October," Copeland said.

Philadelphia is divided into three sections, and each is sprayed once a week. The chemical is very effective, and is keeping Philadelphia from having a bad mosquito problem, Copeland said.

Each year, a technician is brought in to calibrate the spray mechanism. Additionally, each year members of the street crew are sent for training and return to update the rest of the crew on any new developments related to the insecticide spraying.

Other than its use in mosquito control, Malathion is one of the most popular garden home and crop insecticides. It breaks down very rapidly, so is good for these applications.

Dr. Blake Layton, Extension cotton specialist, said Malathion is one of the safest cotton insecticides available.

"Malathion is considerably less toxic than many of the other insecticides that are traditionally used to control boll weevils," Layton said.

Boll weevil eradication efforts in the hills region of Mississippi are well underway currently, but will lessen as the program makes progress. Spray treatments do not follow set intervals, but are made only when a certain number of boll weevils are trapped in a field.

"As each year progresses, fewer treatments are needed," Layton said. "Three or four years down the road, we'll eliminate the need to spray for boll weevils. That will also reduce the need to spray for other cotton pests because we're able to use beneficial insects more to help control the pests."

Malathion is being used to control boll weevils only in the eradication areas of Mississippi. Cotton growers elsewhere must treat boll weevils on their own, and usually use more toxic substances, Layton said.

Contact: Dr. Doug Gaydon, (601) 325-2983