Fruit fly discovery puts part of Alameda County into quarantine

FREMONT — The spotting of a single mated female Mediterranean fruit fly has sent 71 square miles of southern Alameda County into a quarantine as officials focus on eradicating the invasive pest, the California Department of Food and Agriculture’s Plant Health and Pest Prevention Services Division announced Friday.

Residents and any growers, wholesalers and retailers of susceptible fruit are subject to the quarantine. The targeted area has boundaries of Highway 84 on the north, the Alameda and Santa Clara county line on the south, the Don Edwards San Francisco Bay National Wildlife Refuge on the west and Calaveras Creek on the east.

During the quarantine, the first in Alameda County since 1981, home gardeners are encouraged to consume their own produce on site and to not move produce from their properties. Those living in the area can consume, juice, cook, grind in the garbage disposal or otherwise process produce on the property where it was picked. When disposing of produce, it’s recommended to double-bag waste and place it in the regular trash bin instead of the green waste bin, officials said.

“These actions protect against the artificial spread of the infestation to nearby regions where it could affect California’s food supply and backyard gardens,” read the CDFA press release.

The Mediterranean fruit fly, or Medfly for short, is know to target over 250 fruits and vegetables, causing damage when females lay eggs in the produce which then hatch into maggots that burrow through the flesh of the produce, “making it unfit for consumption.”

The CDFA, in partnership with the United States Department of Agriculture and the Alameda County Agricultural Commissioner, plan to eradicate the invasive pest by releasing sterile male fruit flies in a 39-square-mile area around the infestation at a rate of 250,000 male fruit flies per square mile per week, according to the press release.

The sterile males, provided by a sterile insect rearing facility in Los Alamitos operated by the USDA and CDFA, mate with the female fruit flies but do not produce offspring, leaving no new fruit flies to replace the wild ones as they reach the end of their short lives, officials said.

An organic anti-parasite, Spinosad, is being used to treat properties within 200 meters of the detection site and fruit removal will take place on properties within 100 meters of those with mated females, larval detections and multiple adult detections.

“The eradication approach used in this project is the standard Medfly program used by CDFA and is the safest, most effective, and most efficient response program available,” the CDFA said.

Residents with questions about the project or those who believe their produce may be infested with fruit fly larvae may call CDFA’s Pest Hotline at 800-491-1899. Suspected infestations can also be reported via email to reportapest@cdfa.ca.gov.