Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Other
Publication Acceptance Date: 12/1/2009
Publication Date: 12/10/2009
Citation: Backus, E.A., Walker, A. 2009. Feeding Behaviors That Promote Inoculation Of Xylella fastidiosa Are Performed Less By Glassy-winged Sharpshooters on Resistant Vitis Candicans Than On Susceptible V. vinifera cv. ‘Chardonnay’. CDFA Pierce's Disease Control Program Research Symposium, Dec 9-11, 2009, Sacramento, CA. Available:. http://www.cdfa.ca.gov/pdcp/Documents/Proceedings_2009/2009_Program.pdf Interpretive Summary:
Technical Abstract: Development of grape varieties resistant to Pierce’s Disease, caused by the lethal bacterium Xylella fastidiosa (Xf), is considered the most sustainable, long-term solution to the disease. Grape breeders are working to develop varieties resistant to multiplication and spread of the bacterium, by introducing genes from wild grape relatives such as Vitis candicans. However, it is presently unknown whether any grape variety or relative might also be resistant to the feeding of the most economically important vector of Xf, glassy-winged sharpshooter (GWSS). Therefore, electrical penetration graph (EPG) monitoring was used to compare stylet penetration behaviors of GWSS on Xf-resistant V. candicans grape vs. susceptible V. vinifera cv. ‘Chardonnay.’ Frequency of occurrence of X waves (representing the putative Xf 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 an additional mechanism of Xf resistance in V. candicans. This study supports that EPG could be used as a tool for screening host plants for resistance to vector inoculation of Xf, an added resistance trait that could improve the degree of resistance to Xf.