PhotoIs there anything nastier than the common house fly? Not really, when you think about where they hang out.

And, while it's nice that warmer weather is arriving (at least it some parts of the U.S.), the balmier temperatures bring -- that's right -- flies. Dealing with these pests usually means swatters, sprays and other fairly primitive measures.

But now, the USDA’s Agricultural Research Service is working with a virus that can prevent them from reproducing. And, birth control for flies means fewer of them to spread harmful pathogens such as Salmonella or E. coli, which are harbored in animal feces, to human food sources..

How it works

When house flies are infected with the salivary gland hypertrophy virus, researchers have discovered, females stop producing eggs and males no longer mate.

“It’s a way of managing the fly population at the adult level by limiting its ability to reproduce,” said Entomologist Chris Geden of the Mosquito and Fly Unit at ARS’ Center for Medical, Agricultural and Veterinary Entomology (CMAVE).

Researchers are now trying to figure out how to make sure more of the flies exposed to the virus are infected. The normal infection rate is low -- at about 0.5 to 1%.

The CMAVE team has partnered with researchers at the University of Florida and Aarhus University in Denmark to study two populations of house flies -- one in Florida and one in Denmark.

Both teams found that exposure to a combination of infected flies and water produced the highest infection rate: 56% in the Denmark study and 50% in Florida compared with a rate of 37% at a SGHV “hot spot” at a dairy farm in Gilchrist, Florida.

Practical application

“This is not an insecticide. It’s not something you would put out when people are complaining about flies at picnics and expect to get a fast reduction,” Geden told Agricultural Research magazine. “This would be part of an integrated management program in which you would go out early in the year when natural fly populations are just beginning to increase, hit them with the virus to knock down their reproductive ability, and come back 2 to 3 weeks later and do it again.”

This is one of several interventions being explored by scientists at CMAVE in Gainesville.

Last November, Food Safety News reported on another technique being explored by the team -- one involving the use of a chemical that inhibits fly larvae from growing to adulthood.

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