The U.S. Department of Agriculture Animal and Plant Health Inspection Service (USDA/APHIS) and the California Department of Food and Agriculture (CDFA) expanded the Mediterranean fruit fly (Medfly) quarantine in Alameda and Santa Clara counties in California twice in October.

The expansions are in response to the confirmed detections between Oct. 7 and Oct. 15 of 22 wild female Medflies, 14 of them mated, and 12 wild male Medflies from traps in trees in residential areas.

USDA APHIS and CDFA established the quarantine on Sept. 6, following the detection of a mated wild female Medfly in the city of Fremont in Alameda County on Aug. 28. That Medfly came from a trap in an orange tree in a residential area. The agencies expanded the quarantine on Sept. 11, following the detections of additional flies.

As a result of the latest detections, this quarantine area increased by 38 square miles to 121 square miles. There are 54 acres of 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 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 Alameda and Santa Clara counties to respond to these detections following program guidelines for survey, treatment and regulatory actions.

The APHIS exotic fruit flies website contains a description of the new quarantine area, as well as all current federal fruit fly quarantine areas. USDA APHIS will publish a notice of these changes in the Federal Register.

Additional information on the Medfly quarantine is available from USDA APHIS National Policy Manager Richard Johnson at  richard.n.johnson@usda.gov or by phone at 301-851-2109.