Wednesday, 20 November 2002 - 8:36 AM

This presentation is part of : Ten-Minute Papers, Subsection Cc. Insect Vectors in Relation to Plant Disease, Cf. Quantitative Ecology

Spatial and temporal distribution of sharpshooter vectors of Pierce's disease in the Coachella Valley, California

Charles A. Farrar1, Thomas M. Perring1, and Carmen Gispert2. (1) University of California, Department of Entomology, Riverside, CA, (2) University of California, Cooperative Extension, 82-675 Highway 111, Indio, CA

To study sharpshooter distibution, traps were placed every square mile throughout the Coachella Valley, a 99,000 acre agricultural valley where 14,000 acres of table grapes are grown. These 163 traps were changed each week and the numbers of glassy-winged sharpshooter and the related smoke-tree sharpshooter were counted. Sampling started on May 14, 2001 and traps have been collected weekly to the present. Counts showed that average numbers of GWSS were low throughout the Valley and over the time period that we have sampled. Many of the traps had no sharpshooters on them. There were substantially more GWSS than STSS on most dates. When we looked at vegetation and ecological types surrounding the traps, we found some interesting relationships. We determined that traps next to urban landscapes (residences, edge of communities, etc.) had similar numbers of sharpshooters as did traps not adjacent to these areas. Second, we found that traps adjacent to grapes had no more sharpshooters than did traps not adjacent to grapes, thus it does not appear that vineyards are contributing to sharpshooter numbers at this time. Third, we found that traps adjacent to citrus caught significantly higher numbers of sharpshooters than traps not adjacent to citrus. This suggests that citrus contributed to the sharpshooter abundance in the Coachella Valley. Our recommendation at this time is to monitor citrus carefully, and implement management strategies only where sharpshooters reach high numbers.

Species 1: Homoptera Cicadellidae Homalodisca coagulata (glassy-winged sharpshooter)
Species 2: Homoptera Cicadellidae Homalodisca lacerta (smoke tree sharpshooter)
Keywords: Geographic Information Systems, Epidemiology

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