Peach Fruit Fly

Photo courtesy of California Department of Food and Agriculture 

The Contra Costa County Agricultural Commissioner, in cooperation with the California Department of Food and Agriculture and the U.S. Department of Agriculture, is beginning an extensive survey in response to the detection of three peach fruit flies within the City of Brentwood and one peach fruit fly within the City of Oakley. 

The peach fruit fly (PFF) detections occurred between July 31 and Aug. 14. Treatment will occur to eradicate the peach fruit fly that threatens crops and the natural environment. Residents will be notified if their property is part of the effort. Only three residences in the county are currently impacted. 

The detections were made as part of a coordinated pest prevention system that protects agriculture and natural resources from invasive species with early detection, a key component to successfully eradicate an infestation before it can become established. 

The extensive survey consists of multiple peach fruit fly traps placed in concentric circles going out 4.5 miles in each direction from the peach fruit fly detection sites. Additional PFF detections may trigger a quarantine. 

Following the principles of Integrated Pest Management (IPM), the California Department of Food and Agriculture uses “male attractant” technique as the mainstay of its 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 an organic pesticide, Spinosad, approximately eight to 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 several square miles surrounding the sites where the peach fruit flies were trapped. 

The peach fruit fly is known to attack numerous types of fruits and vegetables. Important California crops at risk include apple, avocado, citrus, cucumber, dates, fig, guava, peach, pear and tomato. Damage occurs when the female lays eggs in the fruit. These eggs hatch into maggots, which tunnel through the flesh of the fruit, making it unfit for consumption.

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. 

Help protect California’s agricultural and natural resources and “Don’t Pack a Pest” ( when traveling or mailing packages. 

Federal, state and county agricultural officials work 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.

For information, visit Additional information may be found at Residents with questions about the project can call the Contra Costa County Agricultural Commissioner’s office at 925-608-6600.