Oriental Fruit Fly Quarantine in Portions of Contra Costa and Santa Clara Counties

Portions of Contra Costa and Santa Clara counties have been placed under quarantine for the Oriental Fruit Fly following the detection of multiple flies in each county. A link to the quarantine maps may be found here: www.cdfa.ca.gov/plant/off/regulation.html

In Contra Costa County, detections near the cities of Brentwood and Oakley have resulted in a quarantine zone covering 99 square miles, bordered on the north by the San Joaquin River; on the south by Marsh Creek State Park; on the west by Black Diamond Mines Regional Preserve; and on the east side by the Old River.

In Santa Clara County, detections in the cities of Santa Clara and Sunnyvale have resulted in a quarantine zone covering 112 square miles, bordered on the north by Coyote Creek; on the south by Saratoga; on the west by Mountain View; and on the east by Alum Rock.

California crops at risk include citrus, pome, stone fruits, dates, avocados and many vegetables, particularly tomatoes and peppers. Residents who are living within the quarantine area are being urged not to move homegrown fruits and vegetables from their property. However, they may be consumed or processed (i.e., juiced, frozen, cooked or ground in the garbage disposal) on the property where they were picked or disposed of by double bagging and placing in the regular trash, not green waste. Growers, nurseries or other industry operations who may be located in or near the quarantine zone are encouraged to follow regulatory practices set in place by the California Department of Food and Agriculture (CDFA).

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 an organic pesticide, Spinosad, 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.

While fruit flies and other invasive species that threaten California’s crops and natural environment are sometimes detected in agricultural areas, the majority are initially 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 home grown produce from other countries sent to California.

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 infested other regions, most notably Africa and Hawaii.

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

Residents with questions about the project may call CDFA’s Pest Hotline at 1-800-491-1899. Additional information may be found here: www.cdfa.ca.gov/plant/off.