As the 2001 growing season opens under the shadow of glassy-winged sharpshooter, University of California Cooperative Extension is offering an overview of the pest and the diseases it spreads from 8 a.m. to 3 p.m. April 19 at the Visalia Airport Holiday Inn, 9000 W. Airport Dr., in Visalia.
The new pest threatens the San Joaquin Valley's $2.8 billion raisin, table and wine grape industries. If it spreads further north, California's renowned wine industry will be in jeopardy.
At the meeting, noted UC Davis plant pathologist Bruce Kirkpatrick will describe what many believe to be the most promising prospect for the grape industry in the presence of glassy-winged sharpshooters. Kirkpatrick is conducting experiments to determine whether Pierce's disease can be prevented by boosting grapevines' levels of essential plant micronutrients.
"We've already established in the laboratory what concentrations are toxic to the bacteria," Kirkpatrick said. "What we need is to develop a system that gets those nutrients into the grapevine to protect it from infection."
Glassy-winged sharpshooter is established in the Southern San Joaquin Valley, where the entire city of Bakersfield and an area known as the "citrus belt" are heavily infested. Although Kern County was thought to be free of the bacterium that causes Pierce's disease, near the end of last summer 16 infected vines were found.
In Fresno and Tulare counties, small glassy-winged sharpshooter infestations in urban areas were sprayed with insecticides. Those areas are being closely monitored for recurrences and so far appear to be free of glassy-winged sharpshooters.
At the Visalia meeting, UC Cooperative Extension farm advisors will present information about the bacterium that causes Pierce's disease, Xylella fastidiosa, and give the local history of the condition and information on identification and management.
Other diseases caused by strains of X. fastidiosa, including almond leaf scorch and citrus variegated chlorosis, and information on the biology and control of glassy-winged sharpshooters in citrus orchards and vineyards will be covered.
After lunch, the agricultural commissioners from Tulare, Fresno and Kern counties will explain the local distribution of glassy-winged sharpshooters, management measures being taken and regulatory issues involved.
The registration fee is $25, including lunch. To register, send a check payable to "UC Regents" to UC Cooperative Extension, Tree & Vine School, 2500 W. Burrel Ave., Visalia, CA 93291-4584. The registration deadline is April 16.
For more information contact Kevin Day or Bill Peacock at (559)733-6363.