USDA grant funds sharpshooter research

USDA is throwing money at a small pest traveling with a microscopic lethal weapon. The agency awarded a $1.75 million to University of California-Riverside and professor Leonard Nunney to study glassy-winged sharpshooter and Xylella, the pathogen responsible for severe damage to grape, nut and ornamental crops.

There are four main Xylella subspecies -- three in North America and one in South America. The South American variety feeds on citrus but it has not crossed the U.S. border, Nunney said.

Among the North American varieties, the subspecies fastidiosa -- the one that causes Pierce’s disease -- is found on grapes and almonds. The subspecies sandyi infects oleanders, daylilies, magnolias and jacarandas. Subspecies multiplex’s hosts are almonds, brittlebushes, sages, olives, oaks, plums and peaches.

New Xylella strains are evolving, thus complicating the research being done on the bacterium. Each of the new strains of Xylella identified so far attacks different plants than the original Xylella subspecies.

“That’s worrisome. Clearly, we need to know more about the genetic basis of host specificity,” he said.

In the next four years, Nunney and his research group will develop a nationwide map of different subspecies of Xylella, and an effective monitoring system both to catch foreign forms introduced into the United States and new forms evolving within the country.

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For more: Leonard Nunney, University of California-Riverside, (951) 827-5011; leonard.nunney@ucr.edu.