Bay Area/ San Jose

Santa Clara County Expands Medfly Quarantine Zone in San Jose Amid New Detections

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Published on November 14, 2025
Santa Clara County Expands Medfly Quarantine Zone in San Jose Amid New DetectionsSource: Scott Bauer, U.S. Department of Agriculture, Public domain, via Wikimedia Commons

The battle against the invasive Mediterranean fruit fly, commonly known as the Medfly, continues in Santa Clara County, with agricultural officials expanding the quarantine zone. According to a recent announcement from the Animal and Plant Health Inspection Service (APHIS) and the California Department of Food and Agriculture (CDFA), two expansions occurred shortly after more flies were detected on residential properties in San Jose.

On October 21, two mated female Medflies were found in a San Jose fig tree, leading to the expansion of a quarantine to under one square mile on October 30. Just a few days later, last Monday, the quarantine grew by seven square miles after the discovery of another female Medfly in a fig tree, and a mated female in a persimmon tree. The total quarantine area now spans 205 square miles, encompassing 47 acres of commercial agriculture; however, no additional commercial areas have been included, according to APHIS.

The main goal of these measures is to prevent the critters from reaching non-infested parts of the United States and to avoid impacting foreign trade with the introduction of these pests. APHIS and CDFA, along with local Agricultural Commissioners, are following established protocols for surveying, treating, and implementing regulatory actions against the Medfly invasion. Affected crops within the quarantine area include grapes, olives, oranges, peppers, stone fruits, and tomatoes, as noted on the APHIS website.