Population dynamics and feeding preference of the glassy-winged sharpshooter (Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), vector of Xylella fastidiosa, on southern highbush blueberry

 

Abstract: Bacterial leaf scorch, caused by the xylem-limited bacterium Xylella fastidiosa, is a new disease of southern highbush blueberry in Georgia and Florida. The bacterium is transmitted by xylem-feeding leafhoppers in other crops such as grape or peach. The seasonal variation of leafhopper species was studied on blueberry cultivars with different levels of field resistance to bacterial leaf scorch (Emerald, Star, and FL 86-19 having low, moderate, and high susceptibility, respectively) at two sites in southern Georgia in 2009 and 2010. Sampled on plants, leafhoppers were first detected in May with greatest abundance from June through August and early September. The glassy-winged sharpshooter (GWSS), Homalodisca vitripennis, was the most abundant vector species on all cultivars. GWSS numbers on Emerald were higher than on FL 86-19 or Star, an observation that was confirmed in greenhouse choice tests investigating the feeding and settling preference of field-collected GWSS adults on caged, potted plants of the three cultivars. Thus, field resistance to bacterial leaf scorch appears to be independent of GWSS feeding preference, suggesting that resistance is mediated via the pathogen rather than the vector.