TRANSMISSION OF XYLELLA FASTIDIOSA TO ALMONDS BY THE GLASSY-WINGED SHARPSHOOTER

• Author(s): Purcell, Alexander;
• Abstract: The glassy-winged sharpshooter or GWSS (Homalodisca coagulata) is a newly introduced vector of Xylella fastidiosa, the causal agent of almond leaf scorch (ALS) and Pierces disease (PD) of grapes (Blua et al. 1999, Purcell and Saunders 1999). GWSS and ALS now occur in Kern, Tulare, and Fresno counties. The introduction of GWSS is expected to dramatically increase ALS from its very low levels currently in the southern Central Valley over the coming years. Our experiments are designed to determine the efficiency of transmission (acquisition and inoculation) of X. fastidiosa to almond by GWSS to new growth and to mature ( 1 year) woody tissues of almond and to estimate natural populations of this bacterium within almonds at different times during the growing season. Population densities of X. fastidiosa are important in how efficiently vectors of X. fastidiosa can acquire the bacterium from plants. Pruning branches on trees with early symptoms was promising for control of ALS (Mircetich et al., unpublished progress reports to Almond Board in 1970s), but feeding of GWSS on larger branches may defeat the effectiveness of pruning and increase the importance of almond to almond transmission of X. fastidiosa (Purcell and Saunders, 1999).
• Publication Date: Dec 2001
• Journal: 2001 Pierce's Disease Research Symposium