NEW ALLY IN THE FIGHT AGAINST THE GLASSY-WINGED SHARPSHOOTER

“Winterized” wasp is sharpshooter’s natural enemy

SACRAMENTO  - The California Department of Food and Agriculture’s (CDFA) Glassy-Winged Sharpshooter/Pierce’s Disease Control Program has received approval from the U.S. Department of Agriculture (USDA) to import, breed and release a tiny, stingerless wasp that is a natural enemy of the glassy-winged sharpshooter.

Brought in from Minnesota, Anagrus epos is capable of surviving winter weather—an advantage that allows it to lay in wait in early spring and parasitize sharpshooter eggs as soon as the pest’s breeding cycle begins. Other parasitic wasps utilized in the program are dormant during that period. The new wasps will be released as part of the department’s ongoing efforts to limit the spread of the sharpshooter, which can spread the fatal Pierce’s disease in grapevines and similar diseases in other crops and plants.

“Agriculture is an industry whose success depends on continuous, incremental improvements,” said CDFA Secretary A.G. Kawamura. “A discovery like this one gives our growers an important tool that is relatively inexpensive, environmentally benign, and proven effective.  That’s progress, and it gets us one step closer to success in our fight against the glassy-winged sharpshooter.”

Parasitic wasps seek out sharpshooter eggs and lay its own eggs inside them. The emerging wasps eat through the sharpshooter eggs on their way out, and can serve as a remarkably effective method of reducing the number of sharpshooters that emerge during any given breeding cycle.

As an added advantage, Anagrus epos produces as many as 10 offspring per sharpshooter egg, compared to just one from other wasps. It is capable of building up large populations more rapidly than other parasitic wasps, so it can more thoroughly seek out and control sharpshooter populations.

“We have spent the past five years working to limit the spread of the glassy-winged sharpshooter,” said Pierce’s Disease Program Statewide Coordinator Bob Wynn.  “During that time, our scientists have worked with the USDA and researchers in our universities to give us new alternatives such as this tiny wasp.  This discovery will aid our efforts to control this pest until researchers can arrive at a long-term solution to the problem of Pierce’s disease.”

The sharpshooter biocontrol program began in 2000 at U.C. Riverside, with scientists there producing and releasing wasps. The Arvin Field Station near Bakersfield and the Mount Rubidoux Field Station in Riverside have greatly expanded production, and the program released its one millionth wasp in 2004.

Pierce's disease is caused by the bacterium Xylella fastidiosa, which sharpshooters spread as they feed. The bacterium causes similar diseases in almonds, stone fruits and other crops and plants.  For additional information on the glassy-winged sharpshooter and Pierce’s disease, please visit www.cdfa.ca.gov/phpps/pdcp.

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