Parts of California Are Under Quarantine For Invasive Fruit Fly

In July 2023, the California Department of Food and Agriculture (CDFA) placed parts of Los Angeles County under quarantine for the invasive Tau fruit fly. The impacted area of Stevenson Ranch is 30 miles northwest of downtown Los Angeles. 

Stevenson Ranch is just 90 miles from the Central Valley, which grows around 250 different crops, with an estimated $17 billion yearly value. This area also produces 25 percent of the Nation’s food, including 40% of the Nation’s fruits, nuts, and other table foods.

In a statement, the CDFA said:

“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.

“It’s believed the fly was introduced by travelers bringing uninspected produce into the state — a common pathway for invasive species.”

This past month, Santa Clara County stated that “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 two alerts are reminders of the danger that invasive species pose to California’s biodiversity and represent the potential to harm our unique environment.

Western Plant Health members work with farmers and government agencies to preserve California’s delicate ecosystem by implementing responsible pest control programs.

Bactrocera dorsalis fruit fly


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