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POSTERS: Pathogenicity and host specificity

Infection of blueberry cultivar Emerald with a California grapevine strain of Xylella fastidiosa and acquisition by glassy-winged sharpshooter
Michael O'Leary - USDA-ARS. Lindsey Burbank- USDA-ARS, Mark Sisterson- USDA-ARS

Bacterial leaf scorch disease caused by Xylella fastidiosa (Xf) occurs in southern highbush blueberry varieties in the southeastern United States. However, blueberry cultivar susceptibility to Xf is variable and these interactions are often specific to the pathogen strain. In the San Joaquin Valley of California where Pierce’s disease in grapevines caused by Xf subsp. fastidiosa has been problematic over the last twenty years, blueberry acreage of southern highbush cultivars is expanding, but little is known concerning the potential for spread of Xf from grape to blueberry in this area. Glassy-winged sharpshooter (Homalodiscus vitripennis), a major vector of Xf in the San Joaquin Valley is known to feed on blueberry suggesting potential for emergence of bacterial leaf scorch in California if susceptible blueberry cultivars are planted near Xf infected grapevines. Experimental inoculations showed that a California Pierce’s disease strain of Xf subsp. fastidiosa (Bakersfield-1) causes disease in blueberry cultivar Emerald, and glassy-winged sharpshooter was able to acquire Xf Bakersfield-1 from artificially inoculated blueberry plants under laboratory conditions. The possibility for spread of Xf between blueberries and nearby vineyards has implications for area-wide disease and vector control in the San Joaquin Valley and other regions where these two crops are grown.