PARASITIC WASPS ON THE JOB AGAINST GLASSY-WINGED SHARPSHOOTER
Limited Releases Underway

A tiny, stingerless parasitic wasp that was imported from Mexico and bred at the University of California, Riverside, is now being released in limited numbers in Riverside County by UCR, working together with the California Department of Food and Agriculture(CDFA). Additional releases are planned soon in Ventura, Kern, Tulare and Fresno Counties.

The wasp is another tool in the fight against the glassy-winged sharpshooter and Pierce's Disease, which have already wiped out $40 million in grapevines in the Temecula-area and are threatening a region in Central California that produces $2.8 billion each year in wine, raisin and table grapes.

The glassy-winged sharpshooter, which carries Pierce's Disease from plant to plant, has infested Riverside, San Diego, San Bernardino, Ventura, Orange, Santa Barbara, Los Angeles, Kern, Fresno, Sacramento and Tulare counties. Governor Gray Davis signed legislation in May providing $6.9 million to fight the sharpshooter, with a similar amount earmarked for the following budget year. Also, the Governor pursued federal assistance, bringing an additional $22 million. The governor's funding effort is a primary reason why the parasitic wasps are being put into service so quickly.

"This is a critical piece of the Davis Administration's action plan against the glassy-winged sharpshooter, said CDFA Secretary William (Bill) J. Lyons, Jr. " We intend to use the wasps along with other control programs to try to control the sharpshooter's movement."

Entomologists from UCR and the CDFA found and identified a natural enemy of the glassy-winged sharpshooter called Gonatocerus triguttatus. The wasp is successfully parasitizing the sharpshooter in Mexico and Texas, by laying its eggs inside those of the larger sharpshooter. Professor Mark Hoddle of UCR led a seven-month breeding and quarantine program, funded by the CDFA and the USDA.

These first official releases will be followed by an ongoing breeding and release program in grape-growing areas infested or threatened by the glassy-winged sharpshooters, including Bakersfield, Fresno and the Napa Valley.

UCR will continue to monitor how well the wasp does in the dry heat of California, how successfully it reproduces, and how well it is able to find and parasitize the eggs of the glassy-winged sharpshooter.

"Our primary goal is to set up stable populations of the wasp in California," Morgan said.

For more information, visit the Internet at www.cdfa.ca.gov, or at danr.ucop.edu/news/mediakit/gwss.shtml.