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News Release

California Department of Food and Agriculture

Media Contacts: CDFA Public Affairs, (916) 654-0462,

California Department of Food and Agriculture
Release #18-040
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SACRAMENTO, July 3, 2018 – The California Department of Food and Agriculture (CDFA), the United States Department of Agriculture (USDA), and the Los Angeles County Agricultural Commissioner’s Office have eradicated a Mediterranean fruit fly (Medfly) infestation centered around the Sun Valley neighborhood in northern Los Angeles County, ending a 129-square-mile quarantine that began August 30, 2017.  A total of 42 flies and well over 100 larvae were detected, indicating a breeding colony.
“Detecting and eradicating invasive, exotic pest infestations is an important way to protect our food supply and our environment,” said CDFA Secretary Karen Ross. “Our response to Medfly infestations has evolved and improved over the years to the point where we have developed environmentally friendly techniques that allow us to respond quickly, confidently and effectively.”
CDFA used the release of sterile male Medflies at a minimum rate of 500,000 flies per square mile per week as the mainstay of its eradication measures for this pest.  Additionally, properties within 200 meters of the detection sites were treated with an organic formulation of Spinosad, which originates from naturally-occurring bacteria in soil, in order to eliminate any mated females and reduce the density of the population.  To further reduce the population, properties within 100 meters of breeding populations were subject to host fruit removal to eliminate eggs and larvae.  During this incident, over 115,000 pounds of fruit were removed from over 750 properties.
The sterile fly release program has a proven track record of eradication in California.  Sterile male flies mate with fertile female flies in the natural environment but produce no offspring.  The fly population decreases as the wild flies reach the end of their natural life span with no offspring to replace them, ultimately resulting in the eradication of the pest.  The sterile male Medflies are brought to California by the joint CDFA/USDA sterile insect rearing facility in Los Alamitos, California, which prepares sterile flies for release everyday over the Los Angeles basin.
USDA, CDFA and the Los Angeles County Agricultural Commissioner acknowledge and thank local area residents for their cooperation in preventing the movement of backyard fruit and allowing property access to perform critical eradication activities.  Working together, we rid California of this invasive species.
The Medfly is known to target more than 250 types of fruits and vegetables, potentially causing severe impacts on California agricultural exports and backyard gardens alike.  Damage occurs when the female lays eggs inside the fruit.  The eggs hatch into maggots and tunnel through the flesh of the fruit, making it unfit for consumption.
While fruit flies and other pests that threaten California’s crops and natural environment are sometimes detected in agricultural areas, the vast majority are found in urban and suburban communities.  The most common pathway for these pests to enter the state is by “hitchhiking” in fruits and vegetables brought back illegally by travelers as they return from infested regions of the world.  Help protect California’s agricultural and natural resources; please Don’t Pack a Pest ( when traveling or mailing packages.
The Medfly is found in much of Africa, southern Europe, Middle East, Western Australia, and Central and South America.  It is also present in Hawaii.

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