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Oriental Fruit Fly Quarantine Declared in Portion of Santa Clara County

A 112-square-mile area that includes the cities of Santa Clara and Sunnyvale and parts of seven other cities will remain under quarantine into 2024 as state authorities work to eliminate the invasive pest

SANTA CLARA COUNTY, CALIF. – The California Secretary of Agriculture has placed a 112-square-mile portion of Santa Clara County under quarantine for the oriental fruit fly following the detection of eight flies in the cities of Santa Clara and Sunnyvale. The quarantine area includes all of Santa Clara and Sunnyvale and portions of Campbell, Cupertino, Los Altos, Milpitas, Mountain View, San José and Saratoga.

These areas will likely remain under quarantine until June 1, 2024. The California Department of Food and Agriculture (CDFA) will treat the area near where the flies were trapped to eliminate the insects – likely through early March 2024.


To prevent the spread of oriental fruit flies, the County of Santa Clara Division of Agriculture urges residents in the quarantine area not to move homegrown fruits and vegetables from their property. These fruits and vegetables may, however, be consumed or processed (e.g., juiced, frozen, cooked or ground in the garbage disposal) on the property where they were grown. Affected residents may also dispose of homegrown fruits and vegetables by double-bagging and sealing them and placing them in their regular trash bins, not in bins designated for organic material and food scraps.

The oriental fruit fly is an invasive pest that poses a significant threat to California’s multibillion-dollar agricultural industry. It is native to Asia and has spread to multiple Pacific Islands, including Hawaii. It is known to infest more than 230 types of fruits and vegetables, including such valuable California crops as avocados, apples, stone and citrus fruits, tomatoes and peppers. The value of California crops threatened by the fruit fly in 2020 was $19.3 billion, according to the CDFA.

The most common ways for the oriental fruit fly to enter California are when:

  • Residents accidentally bring prohibited fruits and vegetables back from their travels or receive packages of homegrown produce through the mail.
  • Smugglers intentionally circumvent agricultural checks to bring tropical fruit into the state.

County of Santa Clara Agricultural Commissioner Joe Deviney said it’s critical for county residents to follow federal and state laws governing what they are allowed to bring home when traveling.

Map of the area in Santa Clara County under quarantine for the oriental fruit fly in August 2023.

As a consumer, if you notice that someone is selling tropical fruit online at high prices and you don’t see that type of fruit displayed prominently in local stores, that should be a red flag that something isn’t right. If you have any questions about what items are permitted to bring into California, or if you happen to buy tropical fruit and find insects or larvae inside, please call the CDFA Pest Hotline at (800) 491-1899.

“It would be disastrous for the oriental fruit fly to get established in Santa Clara County and California,” Deviney said. “We all need to be vigilant in protecting our agricultural and natural resources. Please do not bring or ship any fruits, vegetables or plants into California without ensuring they are permitted by law.”

Some businesses will be affected by this quarantine, which took effect on Sept. 1. There are only a few farms in the quarantine area, but there are many plant nurseries, businesses that sell fruits and vegetables outdoors, farmers markets and street vendors. The County will enter into compliance agreements with these entities to ensure no infested plant material leaves the quarantine area and spreads the infestation.

The CDFA will work to eradicate the fruit flies by applying bait high on street trees, utility poles and other surfaces within a roughly 1.5-mile radius of the spots where the flies were discovered. The bait contains a natural compound called methyl eugenol, which attracts the flies, and an organic pesticide known as spinosad, which kills them. The small splotches of bait are applied eight to 10 feet off the ground using a pressurized gun. This approach has successfully eliminated dozens of fruit fly infestations from California over the last several decades.

Oriental fruit flies are larger than common houseflies. They lay eggs under the skin of host fruits. When the eggs hatch into larvae, they tunnel through the flesh of the fruit, making it unfit for human consumption.

Because the larvae can remain hidden within the fruit for up to 10 days, they can “hitchhike” into California undetected. That’s why it’s important for the public to remember not to pack any pests when traveling or mailing packages. Visit the Don’t Pack a Pest website for more information. If you come across produce that looks like it may be infested, or if you have any questions, you can also contact the County of Santa Clara Division of Agriculture at [email protected] or (408) 918-4600.

Residents with questions about the eradication project may call CDFA’s Pest Hotline at (800) 491-1899. The CDFA has additional information on its oriental fruit fly webpage.

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The County of Santa Clara government serves a diverse, multicultural population of 1.9 million residents in Santa Clara County, Calif., making it more populous than 14 states in the United States. The County provides essential services to its residents, including public health protection, environmental stewardship, medical services through the County of Santa Clara Health System, child and adult protection services, homelessness prevention and solutions, roads, park services, libraries, emergency response to disasters, protection of minority communities and those under threat, access to a fair criminal justice system, and many other public benefits.

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Media Contact: María Leticia Gómez / Aaron Kinney, Office of Communications and Public Affairs, (408) 299-5119, [email protected]

Posted: Sept. 6, 2023