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News Release

California Department of Food and Agriculture

Media Contact: Steve Lyle, Office of Public Affairs, (916) 654-0462,

California Department of Food and Agriculture
Release #05-041
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Release follows detection of two wild Medflies

SACRAMENTO – On Thursday, October 13, the California Department of Food and Agriculture is scheduled to begin aerially releasing sterile Mediterranean fruit flies in a 10-square mile region of San Jose, following the detection of two Medflies in the Santa Teresa area.

The sterile Medflies will be brought in from the joint CDFA/USDA rearing facility in Los Alamitos, which prepares hundreds of millions of sterile flies weekly for release over the Los Angeles Basin. For the San Jose project, 2.5 million sterile Medflies will be released weekly. The flies, sterile males, have a proven track record in Southern California of breeding with wild females to help achieve eradication.

“This program is a great example of research and science working to benefit the public and the environment,” said CDFA Secretary A.G. Kawamura. “It wasn’t very long ago that a Medfly infestation meant spray treatments by helicopter. A lot of Bay Area residents probably remember that. Now we have a solution that relies largely on biological control. It’s a great example of progress offered by integrated pest management principles.”

The sterile project, called the Preventive Release Program, was introduced in 1996 and has been instrumental in redefining Medfly response in California. It has also dramatically reduced the number of  infestations. Between 1987 and 1994, an average of 7.5 Medfly infestations were discovered each year in California. Since the Preventive Release Program began in 1996, there have been just four infestations. The last Medfly infestation in San Jose was in 1992.

In addition to the sterile releases, CDFA is conducting ground treatments in a 200-meter radius—about one-eighth of a mile—from the locations of the two detections. The substance being utilized is the organic compound Naturalyte (active ingredient: spinosad), a naturally occurring extract from bacteria.         

The Medfly can infest over 260 types of fruits and vegetables, causing severe impacts on California agricultural exports and backyard gardens. A permanent infestation would result in estimated annual losses of $1.3 to $1.8 billion.


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California Department of Food and Agriculture Office of Public Affairs
1220 N St., Ste. 214, Sacramento, CA 95814