Differences in stylet penetration behaviors of glassy-winged sharpshooters (Auchenorrhyncha: Cicadellidae) on Xylella-resistant Vitis candicans vs. susceptible Vitis vinifera cv. ‘Chardonnay’

Tuesday, December 15, 2009: 2:59 PM
Room 207, Second Floor (Convention Center)
Elaine Backus , USDA - ARS, Parlier, CA
Andrew Walker , Viticulture and Enology, University of California-Davis, Davis, CA
Electrical penetration graph (EPG) monitoring was used to compare stylet penetration behaviors of glassy-winged sharpshooter (GWSS), a vector of Xylella fastidiosa (Xf), on Xf-resistant Vitis candicans grape vs. susceptible V. vinifera cv. ‘Chardonnay.’ Frequency of occurrence of X waves (representing the putative inoculation behavior) was significantly reduced on V. candicans compared with Chardonnay. In addition, both duration and frequency of ingestion from xylem were significantly lower on V. candicans. Results suggest that reduced inoculation efficiency by GWSS vectors may be one mechanism of Xf resistance in V. candicans. These results support that EPG could be used as a tool for screening host plants for resistance to vector inoculation of Xf.