EPIDEMIOLOGY OF PIERCES DISEASE IN SOUTHERN CALIFORNIA: IDENTIFYING INOCULUM SOURCES AND TRANSMISSION PATHWAYS

• Author(s): Cooksey, Donald; Costa, Heather;
• Abstract: Previous studies on the epidemiology of Pierces disease (PD) of grape in Northern California have described systems dealing with different primary vector species and different alternate host plants than those that are found in the Southern California systems. Understanding the role that other plant species in the Temecula area may play in spread of Pierces disease of grapes could be critical to management decisions. In addition to dealing with different host plants, the feeding habits and host range of the primary vector of the pathogen in Southern California differ from other primary vector species in Northern California. Studies with the insect vector species present in Northern California suggest that the pathogen was primarily spread by vectors moving into vineyards from outside habitats, rather than spreading from vine to vine. There is little information available on the relative ability of the glassy-winged sharpshooter to acquire or transmit the Pierces disease pathogen from vine to vine, or from alternate hosts to grape. Because in many cases the vineyards of the Temecula area are in close proximity to citrus groves, it is critical to know the relative inoculum pressure that citrus and other plant hosts may provide in that area. Knowledge of the source of disease inoculum from vectors, whether from inside or outside the vineyard, will be critical to development of management strategies for disease control, such as the choice and management of plant species surrounding vineyards. Results of these studies, combined with data on seasonal fluctuations of sharpshooter populations, will also allow us to estimate the time of year and the regions where pathogen pressure is the greatest, and management strategies can be adjusted appropriately.
• Publication Date: Dec 2001
• Journal: 2001 Pierce's Disease Research Symposium