fruit fly

California Fruit Fly Quarantines Expanded Again

Daniel CooperCalifornia Corner, Pests, Regulation

fruit fly
Mediterranean Fruit Fly

Agriculture officials expanded the Oriental fruit fly (Bactrocera dorsalis/OFF) quarantine in California’s San Bernardino and Riverside counties on Dec. 22, 2023. On Dec. 27, 2023 and Jan. 17, 2024, they expanded the Mediterranean fruit fly (Ceratitis capitata/Medfly) quarantine in Los Angeles County. The actions were taken by the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (USDA APHIS) and the California Department of Food and Agriculture (CDFA). USDA APHIS announced the expanded quarantines on Feb. 28. 


The expansion of the OFF quarantine is in response to the confirmed detection of a male OFF on Dec. 15 from a trap in a residential area of the city of San Bernardino. As a result of that detection, the Redlands area quarantine increased by 1 square mile to 554 square miles. APHIS and CDFA established the original OFF quarantine on Sept. 27 and expanded the quarantine on Oct. 3 and 12, Nov. 3, 9, 17 and 28, and again on Dec. 5. There are approximately 6,500 acres of commercial agricultural production in the quarantine area.


The expansions of the Medfly quarantine are in response to the confirmed detections of seven wild adult flies between Dec. 6 and 18 from traps in fruit trees in residential areas of the city of Los Angeles. As a result of these detections, on Dec. 27, the Leimert Park area quarantine increased by 17 square miles to 158 square miles.

On Jan. 10, CDFA confirmed the detection of one female Medfly from a McPhail trap in a residential neighborhood, resulting in a 1 square mile expansion to 159 square miles, effective Jan. 17.

USDA APHIS and CDFA established the original Medfly quarantine on Oct. 18 and expanded the quarantine on Nov. 1, 7 and 15, and again on Dec. 5. There is no commercial agriculture in the quarantine area.


USDA APHIS is applying safeguarding measures and restrictions on the interstate movement of regulated articles to prevent the spread of OFF and Medfly to non-infested areas of the United States, as well as to prevent the entry of these fruit flies into foreign trade. USDA APHIS is working with CDFA and the agricultural commissioners of Los Angeles, San Bernardino and Riverside counties to respond to these detections following program guidelines for survey, treatment and regulatory actions.

The expansion of these quarantine areas is reflected on the APHIS fruit fly website, which contains a description of all current federal fruit fly quarantine areas.

Additional information on the quarantine areas is available from USDA APHIS Fruit Fly National Policy Manager Richard Johnson at 301-851-2109 or

See a previous report on these quarantines.Source: USDA APHIS

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