Los Angeles County quarantine in place to halt spread of invasive fly

A roughly 79-square-mile area of Los Angeles County remains under quarantine after 20 invasive Tau fruit flies were detected in an area of Stevenson Ranch, near Santa Clarita, Calif. This the first Tau fruit fly quarantine ever in the Western Hemisphere.

"The fly is native to Asia and is a serious pest for agriculture and natural resources, with a very wide host range, including numerous fruits and vegetables as well as a select range of native plants in California," the California Department of Food and Agriculture said in a news release. 

It’s believed the fly was introduced into the state by travelers bringing produce that was not inspected — a common pathway for invasive species, the release said. 

Preventing spread of the invasive fly

The Tau fly is quite small, measuring about 7 millimeters in length, like that of a housefly. The body is yellow with black markings, with clear wings that have two dark stripes: one along the front margin that ends in a dark spot and one about half as long running diagonal from the wing base, according to the California Department of Food and Agriculture.

To prevent the spread of the invasive species, residents living in the quarantine area are urged not to move any fruits and vegetables from their property. Fresh produce may be consumed or processed at the property where it was picked. Otherwise, fresh produce should be disposed of by double-bagging in plastic and placing the bags in a bin specifically for garbage, the release said.

A strategic approach to eliminate the Tau fruit fly and prevent its spread to new areas is being set into motion by the California Department of Food and Agriculture, along with the USDA and Los Angeles County Agricultural Commissioner.

On properties within 200 meters of detections, that includes inspecting fresh produce for fruit fly larvae. Additionally, properties within 200 meters of detections will be treated with a naturally derived, organic-approved material called Spinosad, which will help remove any live adult fruit flies and reduce the density of the population, according to the release.

Finally, fly traps that incorporate a pheromone lure and a minute amount of pesticide will be used in a wider part of the treatment area, the release said.

Learn more and track the quarantine on the California Department of Food and Agriculture website.