The California Department of Food and Agriculture (CDFA), the United States Department of Agriculture (USDA), and the San Joaquin County Agricultural Commissioner have eradicated an Oriental fruit fly infestation in the Stockton area of San Joaquin County, ending a 118-square-mile quarantine that began late last year.

“Thank you to the growers and residents of this area for complying with the quarantine restrictions and helping us eradicate this infestation,” said CDFA Secretary Karen Ross.  “Through teamwork, we were able to prevent the pest from spreading, as quarantines are designed to do.”

CDFA uses “male attractant” treatment as the mainstay of its eradication measures for this pest.  This approach has successfully eliminated dozens of fruit fly infestations from California since the 1970s, including this recent infestation.  Workers squirt a small patch of fly attractant mixed with a minute amount of pesticide approximately 8-10 feet off the ground on street trees and similar surfaces.  Male flies are attracted to the mixture and perish after contact.

The Oriental fruit fly is known to target over 230 different fruit, vegetable and plant commodities.  Damage occurs when the female lays eggs inside the fruit.  The eggs hatch into maggots and tunnel through the flesh of the fruit, making it unfit for consumption.

While fruit flies and other pests 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 around the world. 

The Oriental fruit fly is found in much of Southern Asia, as well neighboring islands like Sri Lanka and Taiwan.  It is also present in Hawaii.