Grapevine Moth Eradication May Begin Next Week

Eradication efforts to rid Gilroy and surrounding areas of the European grapevine moth will begin as early as next week in an area near the intersection of Day and Watsonville roads, officials announced Monday.

The free process is limited to those properties with grapevines, of which there are about 90, and will start with flower or fruit removal within 500 meters of where the moth was found. More information on the eradication program will be available at an open house Tuesday, from 5-7 p.m. at the San Martin Lions Club, 12415 Murphy Ave. in San Martin.

Three adult moths were trapped in September, the first finding of the moth in Santa Clara County, and resulted in a quarantine that extended from Gilroy to Morgan Hill. Three more moths were trapped within this quarantined area earlier this month, officials said.

The larvae of the moth, not the adult, is the real culprit that wreaks havoc on grapes and other crops and plants. In early spring, the destruction begins on the bud clusters or flowers, then larvae spin a web around the buds or flowers and pupate inside, or under a rolled leaf.

Second- and third-generation larvae are even more damaging by feeding on grapes and exposing the grapes to rot or fungal development, which causes additional damage. The larvae develop during winter under bark or other protected areas then emerge the following spring as adults.

California Department of Agriculture's choice of attack begins with flower and fruit removal, but property owners may opt for an organic compound ground treatment—Bt, or bacillus thuringiensis—which is a naturally occurring extract of bacteria.

In addition to Santa Clara County, nine other California counties have found the moth, including Santa Cruz, Merced, Monterey, Napa, San Joaquin, Fresno, Mendocino, Sonoma and Solano.