Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2005
Publication Date: August 2, 2005
Citation: Baumgartner, K., Warren, J.G. 2005. Role of xyllela fastidiosa populations in systemic riparian hosts and the spread of pierce's disease to grapevines in northern california. American Phytopathological Society Annual Meeting. Technical Abstract: We examined the potential of five riparian hosts (California blackberry, California grapevine, elderberry, Himalayan blackberry, and periwinkle) to serve as important sources of inoculum of a Pierce's disease (PD) strain of the pathogen, Xylella fastidiosa (Xf) to vineyards on California's North Coast. For each host, replicate potted plants infected with Xf and noninoculated controls were maintained in screenhouses at two locations (Mendocino, Napa), and were assayed repeatedly from 2003-2004, by culturing and real-time PCR, to quantify seasonal Xf populations. Periwinkle, Himalayan blackberry, and California grapevine harbored Xf populations above the vector acquisition threshhold at two of four sampling intervals (autumn and summer) at both locations, suggesting that the presence of these species in proximity to vineyards may increase the risk of PD. In contrast, the extremely low detection frequency of Xf in California blackberry and elderberry indicates that these hosts may add little risk of the disease in adjacent vineyards; therefore, efforts expended in removing them may not be repaid with a reduction in disease incidence. The only Xf-positive plants detected in spring at both locations were perwinkle and Himalayan blackberry, suggesting that these invasives may contribute to long-term survival of Xf in areas with low overwinter survival of the vector.