Invasive fruit fly outbreak prompts agricultural quarantine in Santa Clarita Valley

Helena Staszower sprays her horse outdoors.
Helena Staszower, 16, sprays off the dust, and at the same time, cools off her horse Ember, a 7-year-old thoroughbred, at the Oak Canyon Equestrian Center in Santa Clarita in early July.
(Mel Melcon/Los Angeles Times)
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California agricultural officials have placed a 79-square-mile area in Los Angeles County under quarantine because of the presence of an invasive fruit fly.

Residents in and around Stevenson Ranch in the Santa Clarita Valley are urged not to move any fruits and vegetables off their property in the hopes of containing the Tau fruit fly, described by the California Department of Food and Agriculture in a press release earlier this week as a “serious pest for agriculture and natural resources with a very wide host range.”

Agriculture officials have detected more than 20 flies, which are native to Asia, in the area. They described the quarantine as the first of its kind in the Western Hemisphere. It’s believed that the fly was introduced to the region by travelers bringing uninspected produce into California.


Stevenson Ranch residents may still consume or process fruits and vegetables at the property where they are picked, but are asked to throw out any leftover produce in double-bagged plastic bags placed in garbage bins.

Federal, state and local agricultural officials plan to eradicate the fly, which is about the size of a housefly with black and yellow markings. Officials will inspect fruit and vegetables where the fly has been present or nearby for larvae, properties will be treated with Spinosad, a natural insecticide, and will set fly traps in a broader area.