Fruit flies detected in Sacramento County — fight to keep invasive species in check launched

Sacramento County is launching an extensive survey and eradication plan in response to the detection of four male oriental fruit flies near Wilton, authorities announced Thursday.

Working with the California Department of Food and Agriculture and the U.S. Department of Agriculture, the county Agricultural Commissioner will launch eradication efforts in the southeast portion of the county in response to the July 19 detection, according to a Sacramento County news release.

Widespread throughout the mainland of southern Asia and neighboring islands, the oriental fruit fly is known to target over 230 different types of produce, including pome, stone fruits, citrus, dates, avocados, peppers and tomatoes, according to the release. The female Bactrocera dorsalis lays eggs inside the fruit, which hatch into maggots that tunnel through the fruit’s flesh, rendering it unfit for consumption.

The 8-millimeter yellow insects are considered an invasive species, and typically enters the state by “hitchhiking” on produce sent to California or brought back illegally by travelers visiting infested regions, according to the release. The insects can do significant damage to agricultural and natural resources but do not pose threats to humans, officials say.

Sacramento County Agricultural Commissioner Chris Flores urged residents to be “vigilant” when it comes to the transportation of potentially-infected fruit into the state.

“Invasive non-native fruit flies are serious pests for California’s agricultural industry and backyard gardens,” Flores said. “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.”

If more are found, state officials could trigger a quarantine similar the one placed on a 123-square-mile area in Sacramento and Yolo counties in 2019. That effort successfully eradicated the insect nine months after the infestation was first reported.

Male annihilation technique to be deployed

To control the spread of the fruit flies in the area, authorities will launch a delimitation survey, placing fly traps in concentric circles extending 4½ miles in each direction from the area where the four flies were originally detected.

The eradication effort is guided by a “male attractant” technique, according to the release. Workers mix fruit fly attractant with a small dose of organic pesticide and apply them on trees approximately 8 to 10 feet off the ground. Male fruit flies are attracted to the mixture and die after consuming it.

The male annihilation technique (MAT) is typically applied for a period of two life cycles of the fly, approximately 60 days.

That effort is being carried out in an area extending about 1½ miles from the original fruit fly detection site. According to county officials, the male attractant method of eradication has successfully eliminated dozens of potential fruit fly infestations in the state.

Before shipping or traveling with food or plants, make sure to check whether they are legal and safe at dontpackapest.com. Residents with questions may call the Sacramento County Agricultural Commissioner’s office at 916-875-6603.

This story was originally published July 28, 2022 at 12:49 PM.