Medfly Infestation Triggers Quarantine in Central Los Angeles Area

Dan Citrus, General

Mediterranean fruit fly (Medfly)

Mediterranean fruit fly (Medfly)

cdfa-logoSACRAMENTO, March 24, 2014 – A quarantine has been declared due to a Mediterranean fruit fly (Medfly) infestation detected in city of Los Angeles. One adult male and five unmated females were detected in five traps between March 3 and 12, 2014, and four larvae were discovered in backyard fruit on March 18. The United States Department of Agriculture (USDA), the Los Angeles County Agricultural Commissioner, and the California Department of Food and Agriculture (CDFA) are working collaboratively on this project.

The 88-square mile quarantine is in central Los Angeles, near the University of Southern California. It is bordered on the north by West Temple St, on the south by E. Imperial Hwy, on the west by S. La Cienega Blvd, and to the east by I-710. Additional information, including a map of the 88-square mile quarantine zone, is available at:

To eradicate the infestation, the increased release of sterile male Medflies began last week, at a rate of 250,000 flies per square mile per week, double the normal rate in that area. The enhanced release area is approximately 25 square miles. In addition, properties within 200 meters of detections are being treated with an organic formulation of Spinosad, which originates from naturally-occurring bacteria, in order to eliminate any mated females and reduce the density of the population. Finally, fruit removal will occur within 100 meters of the larval detection property in order to remove any fruit infested with eggs and larvae.

“Our pest prevention system to detect and respond to invasive species like the Mediterranean fruit fly is working well and according to design,” said CDFA Secretary Karen Ross. “The release of sterile Medflies is a proven method of eradicating an infestation. The key is to move swiftly and take action before the pests can cause widespread damage and become established.”

The quarantine will affect any growers, wholesalers, and retailers of susceptible fruit in the area as well as local residents – home gardeners are urged to consume homegrown produce on site and not move it from their property. These actions protect against the artificial spread of the infestation to nearby regions where it could affect California’s food supply and our backyard gardens.

The sterile male Medflies are brought to California by the joint CDFA/USDA sterile insect rearing facility in Los Alamitos, which prepares sterile flies for release everyday over the Los Angeles Basin. The sterile release program has a proven track record of eradication in southern California. Sterile male flies mate with fertile female flies in the environment but produce no offspring. The Medfly 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 Medfly can infest more than 250 types of fruits and vegetables, causing severe impacts on California agricultural exports and backyard gardens alike. Residents who believe their fruits and vegetables are infested with fruit fly larvae are encouraged to call the state’s toll-free Pest Hotline at 1-800-491-1899.

The eradication approach in the Los Angeles area is the standard Medfly program used by CDFA and it’s the safest, most effective and efficient response program available. CDFA has successfully eradicated each and every detected Medlfy infestation in California history, dating back more than 30 years.

Regulation and quarantine bounderies.

Credit: California Department of Food and Agriculture