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European Grapevine Moth Eradication to Start in Gilroy

Open House Meeting Scheduled for Residents

SANTA CLARA COUNTY, CALIF. – The Santa Clara County Department of Agriculture and the California Department of Food and Agriculture (CDFA) are taking steps to eradicate the European Grapevine Moth (EGVM) from an infested area near the intersection of Day Road and Watsonville Road in Gilroy. Eradication activities focus on intensive trapping in vineyards and the treatment of backyard grapevines.

Approximately 90 properties are within the designated treatment areas. Only properties with grapevines will be treated. Flower/fruit removal activities are scheduled to begin in the Gilroy area as early as next week. An informational open house to discuss the eradication program is scheduled for Tuesday, April 12, 2011, from 5:00-7:00 p.m. at the San Martin Lions Club, 12415 Murphy Avenue, San Martin, CA.

The EGVM larvae, not the adult moths, are responsible for the damage to grapes. Larvae (worms) emerge early in the spring and feed on grape bud clusters or flowers. The larvae then spin webbing around them before pupating inside the web or under a rolled leaf. If heavy flower damage occurs during this first generation, the affected flowers will fail to develop and yield will be reduced. Second-generation larvae chew into the grapes to feed before pupating in the clusters or in leaves. Larvae of the third generation, the most damaging generation, feed on multiple ripening grapes and expose them to further damage from fungal development and rot. These larvae overwinter as pupae in protected areas such as under bark, and emerge as adults the following spring.

CDFA’s first choice for treatment is flower and fruit removal from backyard grapevines within 500 meters of where EGVM was found. If property owners prefer otherwise, the second choice is ground treatment with the organic compound Bt, or bacillus thuringiensis, a naturally-occurring extract from bacteria. The treatment options will be provided at no cost to the homeowners. Both options will help to eradicate EGVM and greatly reduce the risk of spread to commercial vineyards.

To date, EGVM has been detected in ten California counties: Fresno, Merced, Monterey, Napa, San Joaquin, Santa Clara, Santa Cruz, Sonoma, Solano and Mendocino. The pest is known to occur in southern Asia, Japan, Europe, and North and South America. EGVM primarily damages grapes, but is also known to feed on other crops and plants.

EGVM was first detected in Santa Clara County when three adult moths were trapped in September 2010. This led to the establishment of a regulatory quarantine extending from Morgan Hill to Gilroy. Earlier this month, three additional EGVM were trapped within the quarantined area.

For more information on EGVM, visit CDFA’s website at: http://www.cdfa.ca.gov/phpps/egvm/index.html.

Media Contact: Kevin O’Day, Director, Agriculture and Environmental Management, (408) 918-4622 / (408) 690-6962; Steve Lyle, CDFA Information Officer, (916) 654-0462 / slyle@cdfa.ca.gov
Posted: February 11, 2010