Infection of Blueberry Cultivar ‘Emerald’ with a California Pierce’s Disease Strain of Xylella fastidiosa and Acquisition by Glassy-Winged Sharpshooter

Abstract

Bacterial leaf scorch disease caused by Xylella fastidiosa occurs in southern highbush blueberry varieties in the southeastern United States. Susceptibility to X. fastidiosa varies by blueberry cultivar, and these interactions are often strain-specific. Xylella fastidiosa subsp. fastidiosa is the causal agent of Pierce’s disease in grapevines, and it has been problematic in the San Joaquin Valley of California since the introduction of the glassy-winged sharpshooter (Homalodisca vitripennis). The glassy-winged sharpshooter is known to feed on blueberry, a crop that is expanding in the San Joaquin Valley. Currently, little is known about the potential for the spread of X. fastidiosa between grape and blueberry in this region. The ability of a Pierce’s disease strain of X. fastidiosa from the San Joaquin Valley to cause disease in southern highbush blueberry and the potential for the glassy-winged sharpshooter to transmit X. fastidiosa between blueberry and grapevine were investigated. Experimental inoculations showed that the X. fastidiosa subsp. fastidiosa strain Bakersfield-1 can cause disease in blueberry cv. Emerald, and that the glassy-winged sharpshooter can acquire X. fastidiosa from artificially inoculated blueberry plants under laboratory conditions. Understanding the possibility for X. fastidiosa strains from the San Joaquin Valley to infect multiple crops grown in proximity is important for area-wide pest and disease management.