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

• Author(s): Chen, Jianchi; Groves, Russell; Bigham, Daniel; Civerolo, Ed; Daane, Kent; Johnson, Marshall; Lin, Hong;
• Abstract: The primary objective of this research was to characterize the seasonal abundance, dispersal, and overwintering biology of the glassy-winged sharpshooter (GWSS), a primary vector of Xylella fastidiosa (Xf). Moreover, to estimate the incidence of Xf detected from GWSS collected in different perennial cultivated and non-cultivated plant species. Based on results of seasonal plant utilization 2004-05, we conclude that host plant species significantly influences 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. Perennial crop species examined included sweet cherry, navel orange, Spanish lemon, olive, avocado, plum, and pomegranate. Dispersing populations of adult GWSS were highest in citrus (lemon and navel) and pomegranate. Adult GWSS were also regularly collected from and observed feeding upon a wide range of non-crop weed species within and surrounding orchard crops. Overwintering adult GWSS were regularly collected in relatively low population densities on citrus (navel and lemon), pomegranate, avocado, plum, and non-crop annual weed species. Spatial patterns of adult GWSS capture within survey orchards varied among perennial crop species. Random distributions of adult GWSS were often observed in reproductive hosts including navel orange and Spanish lemon compared to population aggregates observed in avocado and olive. The presence of Xf in a subsample of GWSS collected among different perennial crops and on non-crop species was determined for collections in 2004 using PCR formats and the frequency of Xf detection in populations of GWSS varied among season in 2004.
• Publication Date: Dec 2005
• Journal: 2005 Pierce's Disease Research Symposium