Asian Gypsy Moth Detected Within the City of Sunnyvale in Santa Clara County

SANTA CLARA COUNTY, CALIF. – The County of Santa Clara Agricultural Commissioner, in cooperation with the California Department of Food and Agriculture (CDFA) and the United States Department of Agriculture (USDA), are beginning an extensive survey in response to the detection of a single Asian gypsy moth (AGM) within the City of Sunnyvale.

The detection was made as part of our coordinated pest prevention system that protects our agriculture and natural resources from non-native invasive species. In keeping with Integrated Pest Management principles, early detection and delimitation play key roles to determine control and containment options.

The extensive survey, also known as a delimitation survey, is triggered after a moth is detected. Traps (see photo) are placed over an 81-square mile area (with up to 36 traps per square mile), within a 25-square mile core area around the initial detection site. There will be approximately 2,300 traps placed in the general vicinity. Traps will be visually inspected weekly.

The traps are designed to determine the presence and extent of any infestation. If an infestation was to develop in the Sunnyvale area, Asian gypsy moth caterpillars would threaten our nearby forests and local oaks as well as many other hardwoods, evergreens, manzanita, cottonwood, willow, and other species. Asian gypsy moths are also a threat to our local agricultural crops such as fruit trees.

Female Asian gypsy moths can fly up to 25 miles and lay up to 1,500 eggs, making early detection of an infestation especially important. Each caterpillar can eat up to one square foot of leaves per day and can feed on hundreds of tree species. The long hairs of the caterpillars (see photo) can cause skin irritation or allergic reactions in some people, including itchy rashes that can last up to two weeks.

The Asian gypsy moth’s egg masses are frequently detected on ships and shipping containers inbound from Asia, Russia, and other infested regions. Eggs are also known to be transported on outdoor furniture, recreational vehicles, firewood, and other portable items. Help protect California’s agricultural and natural resources by learning what you can and cannot bring when traveling with food, plants, or animals. Visit for more information.

Federal, state, and county agricultural officials work year-round, 365 days a year to prevent, deter, detect, and eliminate the threat of invasive species and diseases that can damage or destroy our agricultural products and natural environment. The efforts are aimed at keeping California’s natural environment and food supply plentiful, safe, and pest-free.

Residents with questions are encouraged to call the County of Santa Clara Agricultural Commissioner’s office at 408-918-4600 or the CDFA Pest Hotline at 800-491-1899. 

For more information on the AGM, please visit

If you have seen a new or unusual plant or pest in your area, report it by visiting


The County of Santa Clara government serves a diverse, multi-cultural population of 1.9 million residents in Santa Clara County, California, making it more populous than 14 states in the U.S. The County provides essential services to its residents, including public health protection, environmental stewardship, medical services through the County of Santa Clara Health System, child and adult protection services, homelessness prevention and solutions, roads, park services, libraries, emergency response to disasters, protection of minority communities and those under threat, access to a fair criminal justice system, and many other public benefits.

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Media Contact: Joe Deviney, Consumer & Environmental Protection Agency,    

(408) 642-0440,[email protected]

Posted: July 22, 2020


News Release


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