Stopping Flies Before They Sicken You

(Inside Science TV) -- We know them as unwelcome guests at picnics and outdoor gatherings, but house flies are more than just an annoyance. They can also spread bacteria that can cause diarrhea and other illnesses. Now, scientists are looking for ways to stop these pests before they become a full-blown problem.

USDA’s Chris Geden is a research entomologist, a scientist who studies insects. He has been learning about house flies and ways to kill them for almost 40 years.

“As years have gone by, the flies have become very resistant to all the insecticides,” said Geden. Flies can transmit disease because of the way they consume food. Immediately after landing on a food item, a fly will spit on the food, softening it up so that it can ingest it. This process could transmit diseases like E. coli and salmonella that may be carried by the fly.

“They’re regurgitating organisms that can make you sick,” said Geden.

Geden is looking at two ways to stop flies from bugging you. First, he’s using insect-killing wasps – a fly’s natural enemy – to attack. The wasps sting and consume the fly at its early “pupal” stage.

“They’re sort of like heat-seeking missiles. All they do is spend all day long looking for fly pupae,” explained Geden.

Farmers can purchase the wasps to help control the flies. Lucky for the farmers, the wasps do not sting humans. “They have no other purpose in life but to find and kill flies,” said Geden.

Another way Geden is targeting flies is by using a hormone that stops the fly from maturing.

“This is a synthetic hormone that will keep the fly from ever getting to the larval stage,” said Geden.

Adult flies carry this hormone – known as pryiproxyfen – to their egg-laying sites. Once there, the hormone will prevents larvae from growing. The larvae will eventually die having never become an adult fly. House flies grow quickly and can develop from an egg to an adult in less than seven days. Their typical life span is about 2-3 weeks.

Pryiproxyfen is already being used as a pesticide in flea and tick prevention products for pets.