California State Seal

News Release

California Department of Food and Agriculture

Media Contacts: Steve Lyle (CDFA), 916-654-0462 ,

California Department of Food and Agriculture
Release #23-181
Print This Release




SACRAMENTO, October 24, 2023 – Portions of Ventura and Los Angeles Counties have been placed under quarantine for the Queensland fruit fly (QFF) following the detection of two adult QFFs within the City of Thousand Oaks, in Ventura County.  The quarantine area in Ventura and Los Angeles Counties measures 76 square miles, bordered on the north by Tierra Rejada Golf Club; on the south by Las Virgenes Reservoir; on the west by Wildwood Park; and on the east by Agoura Hills.  A link to the quarantine map may be found here:

The Queensland fruit fly (Bactrocera tryoni), native to Australia, is a serious pest to the State’s agriculture and natural resources, and is known to target over 175 different fruits, vegetables, and plant commodities.  Important California crops at risk include numerous fruits (including grape, strawberry, fig, citrus, avocado, apricot, peach, cherry, nectarine, plum, pear, and apple) and vegetables (including tomato and sweet pepper).  Damage occurs when the female fruit fly lays her eggs inside the fruit.  The eggs hatch into maggots, which tunnel through the flesh of the fruit, making it unfit for consumption.  

“This has been a record year for fruit fly detections,” said CDFA Secretary Karen Ross.  “The stakes are high. Help us protect our commercial and backyard gardens from invasive fruit flies – please ‘Don’t Pack a Pest’ when you travel, and don’t mail packages carrying unmarked fruits and vegetables to California.”

To prevent the spread of fruit flies through homegrown fruits and vegetables, residents living in the Queensland fruit fly quarantine area are urged not to move any fruits and vegetables from their properties.  Fruits and vegetables may be consumed or processed (i.e. juiced, frozen, cooked, or ground in the garbage disposal) at the property where they were picked. If they are not consumed or processed, please dispose of them by double-bagging in plastic bags and putting the bags in the garbage bin for collection, not green waste.

Following the principles of Integrated Pest Management (IPM), the California Department of Food and Agriculture, working in cooperation with the United States Department of Agriculture, the Ventura County Agricultural Commissioner, and the Los Angeles County Agricultural Commissioner will utilize a multi-tiered approach to eliminate QFF and prevent its spread to new areas.  On properties within 200 meters of detections, staff will cut host fruit to inspect for any fruit fly larvae that may be present.  If larvae or mated adult females are found, agricultural officials will hand remove QFF host material (fruits and vegetables) within 100 meters to remove eggs and larvae from the area.  Additionally, properties within 200 meters of detections will be treated with a naturally derived, organic-approved material known as Spinosad, which will help remove any live adult fruit flies and reduce the density of the population. Finally, traps that incorporate a pheromone lure and insecticide targeted for exotic fruit flies to attract and eliminate adult male Queensland fruit flies will be utilized.

The most common pathway for these invasive species to enter our state is by “hitchhiking” in fruits and vegetables brought back illegally by travelers as they return from infested regions around the world or from packages of home grown produce of foreign origin sent to California.  The vast majority of invasive species infestations in California occur not on farms, but in our urban and suburban residential areas.  Consumers are encouraged to refrain from transporting or mailing fruit or other agricultural products into the United States of America and California – Help us protect our agricultural, natural resources, and unique biodiversity from invasive fruit flies - Please Don’t Pack a Pest (

Federal, State and County agricultural officials work year-round to prevent, deter, and eliminate the threat of invasive pests and diseases that can damage or destroy our agricultural products, natural environment, resources, and unique biodiversity.  The efforts are aimed at keeping California’s food supply plentiful, safe, and pest-free.  

Residents with questions about the project may call CDFA’s Pest Hotline at 1-800-491-1899.  Photos and additional information may be found here:



CDFA Protects
Follow CDFA News on Twitter and Facebook
California Department of Food and Agriculture Office of Public Affairs
1220 N St., Ste. 214, Sacramento, CA 95814