A quarantine has been put in place in an area of Los Angeles County due to a Tau fruit fly detection. The California Department of Food and Agriculture (CDFA) reported the discovery of 20 flies near the city of Santa Clarita. It marks the first-ever quarantine for the pest in the Western Hemisphere. The Tau fruit fly is native to Asia and poses a serious threat to agriculture as it has a very wide host range with at least 34 hosts in nine plant families. Avocado, citrus, cucurbits, peppers, and tomatoes are among the California crops most at risk.
CDFA has established a 79-square-mile quarantine zone after the discovery was made in an unincorporated area of Stevenson Ranch in the Santa Clarita Valley. The pest is from the Zeugodacus tau group and is similar in size to a housefly. CDFA notes that the body is yellow with black markings and its clear wings have two dark stripes. One stripe is along the front margin that ends in a dark spot and the other is about half as long, running diagonally from the wing base.
CDFA has delineated the quarantine area as being bordered on the north by Castaic Junction, on the south by Oat Mountain, on the west by Del Valle, and on the east by Honby Ave. Federal, state, and local officials will be working to prevent the spread of the pest into other areas. Officials will be inspecting host plants for fruit fly larvae on properties within 200 meters of detections. Properties will also be treated with a naturally derived organic-approved material known as Spinosad to address adult populations. Fly traps with pheromone lures will also be deployed as part of the mitigation efforts.
The recent Tau fruit fly detection is not the only time the pest has been found in California. In 2016, initial detections occurred in San Bernardino County. Three other re-introductions have occurred since then with each resulting in successful eradication.