EPIDEMIOLOGY OF PIERCES DISEASE IN THE CENTRAL SAN JOAQUIN VALLEY OF CALIFORNIA: FACTORS AFFECTING PATHOGEN DISTRIBUTION AND MOVEMENT

• Author(s): Chen, Jianchi; Groves, Russell; Daane, Kent; Johnson, Marshall;
• Abstract: The overall goal of this project is enhance our present understanding of the epidemiology of Pierces disease (PD) in the central San Joaquin Valley (SJV) of California by elucidating factors that influence its geographical distribution and movement. The objective of this research will be to characterize the seasonal abundance and dispersal biology of the glassy-winged sharpshooter (GWSS), a primary vector of Xylella fastidiosa (Xf), to identify where the vector(s) acquire the pathogen, to determine when vectors move into vineyards and transmit the pathogen to grapes, and to genetically characterize the populations of Xf isolated from GWSS collected in different perennial cultivated and non-cultivated plant species compared to strains present in PD- affected vineyards. Based on preliminary results of seasonal plant utilization by GWSS, we conclude that host plant species can significantly influence GWSS population biology. GWSS adult, nymph, and egg mass densities varied among perennial, cultivated crop plant species and non-cultivated weed species examined in this study including sweet cherry, navel, lemon, olive, avocado, plum, pomegranate, pistachio, and grape. Temporal patterns of GWSS capture, representing dispersal activity of both overwintered and first generation adult GWSS, varied among the perennial crop species examined. Moreover, patterns of adult GWSS capture among the distances sampled along linear transects extending into perennial crops were dissimilar among perennial crops.
• Publication Date: Aug 2003
• Journal: 2003 Pierce's Disease Research Symposium