An invasive species of fruit flies found in areas of Sacramento County has prompted county to take measures to prevent further invasion which will include quarantine for fruits and vegetables in those areas.

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This week, the Sacramento County Agricultural Commissioner, in cooperation with the California Department of Food and Agriculture and the United States Department of Agriculture, have initiated an extensive survey and eradication plan in response to the detection of nine male oriental fruit flies (OFF), Bactrocera dorsalis, near the city of Rancho Cordova and the American River Parkway in Sacramento County.

The initial detection was confirmed on Sept. 12, 2023. The detections were made as part of our coordinated pest prevention system that protects our agriculture and natural resources from invasive species, with early detection as a key component to successfully eradicating an infestation before it can become established.

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The extensive survey, also known as a delimitation survey, consists of multiple oriental fruit fly traps at prescribed densities going out 4.5 miles in each direction from the oriental fruit fly detection sites. These nine OFF will trigger a quarantine, which will be announced shortly by the California Department of Food and Agriculture. 

Following the principles of Integrated Pest Management (IPM), agricultural officials use “male attractant” technique as the mainstay of the eradication effort for this invasive species. This approach has successfully eliminated dozens of fruit fly infestations in California. Trained workers squirt a small patch of fruit fly attractant mixed with a very small dose of Spinosad, a natural pesticide made by a soil bacterium and approved for use on organic crops, approximately 8-10 feet off the ground on street trees and similar surfaces; male fruit flies are attracted to the mixture and perish after consuming it. The male attractant treatment program is being carried out over an area that extends 1.5 miles from each site where the oriental fruit flies were trapped. 

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While fruit flies and other invasive species 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 or from packages of homegrown produce sent to California. Help protect California’s agricultural and natural resources; please Don’t Pack a Pest when traveling or mailing packages.

“Invasive non-native fruit flies are serious pests for California’s agricultural industry and backyard gardens,” said Sacramento County Agricultural Commissioner Chris Flores. “These recent detections remind us that we need to remain vigilant in protecting our agricultural and natural resources. When traveling abroad or mailing packages to California, we urge the public not to bring back or ship fruits and vegetables as they are pathways for oriental fruit flies and other invasive species entering our state.”

The oriental fruit fly is known to target over 230 different fruit, vegetable and plant commodities. Important California crops at risk include grapes, pome and stone fruits, citrus, dates, avocados, tomatoes and peppers. Damage occurs when the female fruit fly lays her eggs inside the fruit. The eggs hatch into maggots, which tunnel through the flesh of the fruit, making it unfit for consumption. 

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The oriental fruit fly is widespread throughout much of the mainland of southern Asia and neighboring islands, including Sri Lanka and Taiwan, and it has invaded other areas, most notably Africa and Hawaii.

Federal, State and County agricultural officials work year-round, 365 days a year, to prevent, deter, detect, and eliminate the threat of invasive species and diseases that can damage or destroy our agricultural products and natural environment. The efforts are aimed at keeping California’s natural environment and food supply plentiful, safe and pest-free. 

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Residents with questions about the project may call the Sacramento County Agricultural Commissioner’s office at 916-875-6603 or the California Department of Food and Agriculture’s Pest Hotline at 1-800-491-1899.