First Ever Tau Fruit Fly Quarantine in Western Hemisphere Imposed in Los Angeles County

In an unprecedented event, a quarantine affecting over 79 square miles of Los Angeles County has been imposed following the discovery of approximately 30 invasive Tau fruit flies. This measure has been taken to prevent the spread of the invasive species and to protect California’s lucrative fruit and vegetable industry. This is the first ever quarantine for the Tau fruit fly in the Western Hemisphere.

The fly, native to Asia, was discovered on June 6 in the unincorporated area of Stevenson Ranch, about 30 miles north of downtown Los Angeles. Officials believe it was likely introduced into California by a traveler carrying uninspected produce.

The California Department of Food and Agriculture announced the quarantine last week. Ken Pellman, spokesperson for Los Angeles County’s Agricultural Commission, emphasized the need to prevent such incidents. Pellman said, “We want to keep an eye out and prevent stuff from coming here in the first place, and if it comes here, to eradicate it quickly before it spreads.” The fly is known to infest around 100 types of fruits including avocados, tomatoes, and watermelons. If the Tau fruit fly continues to spread, it could result in the destruction of crops and the increased use of pesticides to maintain yields.

According to Jason Leathers, Environmental Program Manager at the California Department of Food and Agriculture, the fly’s ability to evade human detection and reproduce faster than other fruit flies present significant risks. “What’s really insidious about it is they use an egg-laying organ to insert the eggs under the skin of fruit, so people don’t realize that their fruit is infested and it looks just fine,” Leathers said.

For now, the infestation has been contained, but officials are urging residents not to move their produce, either home-grown or bought from a market, beyond their homes. Farmers market vendors have started using netting systems to catch the flies and protect their produce.

Traps have now been set up throughout the area, and any produce or plants within 200 meters of a detected Tau fly will be inspected for larvae. “It’s an ounce of prevention versus a pound of cure,” Pellman said.

Brian Brown, Curator of Entomology at the Los Angeles Natural History Museum, warned that if the fruit flies get out of control, they could severely impact California’s produce exports on both a national and global scale. He said, “Once these things get going in a large area they’re almost impossible to eradicate.”