Why is the government dropping millions of flies over the Bay Area?

"This summer, a small number of invasive Mediterranean fruit flies were detected in San Jose. In response, the state started doing something that might seem strange: releasing millions more fruit flies out of airplanes every week to drift down upon the South Bay. (Close your mouth when looking up - kidding!) But these flies are different. They're males that have been exposed to radiation to make them sterile."

"Jason Leathers is the branch chief for Pest Detection/Emergency Projects at the California Department of Food and Agriculture (CDFA). His job is to help fight these teeny-tiny menaces. Though small, the danger they pose is real. Medflies can ruin more than 250 kinds of produce by infecting them with maggots. The department estimates that if the population were uncontrolled, it would cost the state's agricultural industry as much as $1.8 billion a year."

A small number of invasive Mediterranean fruit flies were detected in San Jose, prompting weekly aerial releases of sterile, irradiated male flies to suppress the population. The released males mate with wild females but produce no viable eggs, gradually eradicating the infestation. The sterile-insect technique has succeeded previously in Southern California, Oregon, Florida and Louisiana. Jason Leathers leads Pest Detection/Emergency Projects at the California Department of Food and Agriculture. Medflies are small, brightly colored internal fruit feeders native to the Mediterranean; females lay eggs under fruit skin. Medflies can damage over 250 kinds of produce and could cost California agriculture up to $1.8 billion annually if uncontrolled.

Read at The Mercury News