Official Pest Report

Official Pest Reports are provided by National Plant Protection Organizations within the NAPPO region. These Pest Reports are intended to comply with the International Plant Protection Convention's Standard on Pest Reporting, endorsed by the Interim Commission on Phytosanitary Measures in March 2002.

Zeugodacus tau: APHIS Removes the Quarantine in Los Angeles County, California

Country: United States


Zeugodacus tau: APHIS Removes the Quarantine in Los Angeles County, California

Richard Johnson, Fruit Fly National Policy Manager, at (301) 851-2109 or and Avraham Eitam, Assistant National Policy Manager, at (614) 205-4565 or


On June 28, 2024, the USDA’s Animal and Plant Health Inspection Service (APHIS) and the California Department of Food and Agriculture (CDFA) removed the Zeugodacus tau quarantine in Los Angeles County, California, after three generations elapsed with no additional detections in this area. This action releases the 128 square miles of the Stevenson Ranch quarantine, which contained no commercial agriculture.

APHIS and CDFA established the quarantine on July 11, 2023, following the confirmed detections of nine adult male Z. tau from various sites in Stevenson Ranch between June 7 and July 6, 2023, and expanded the quarantine on August 15, September 14, October 3, and November 15, following detections of additional flies. APHIS and CDFA selected the quarantine release date based on a degree-day model from the date of the last detection, which was December 8, 2023. APHIS restricted the interstate movement of regulated articles from this area to prevent the spread of Z. tau to non-infested areas of the United States. APHIS has worked cooperatively with CDFA and the Los Angeles County Agricultural Commissioner to eradicate this transient Z. tau population through various control actions per program protocols.

The removal of this quarantine area is reflected on the APHIS exotic fruit flies website, which contains a description of all current federal fruit fly quarantine areas. APHIS will publish a notice of this change in the Federal Register.

Under IPPC standards, Zeugodacus tau is considered to be a pest that is absent and eradicated from the United States.

Posted Date: July 5, 2024, 2:07 p.m.