• PD/GWSS Board News

PD/GWSS Board to Refocus Research Efforts

Sacramento, Calif., September 6, 2007 – Significant advances have been made in Pierce’s disease/glassy-winged sharpshooter (PD/GWSS) research since last reviewed in 2004, but gaps in  knowledge still need to be addressed, according to the PD/GWSS Research Scientific Review released last week by the California Department of Food and Agriculture (CDFA) Research Scientific Advisory Panel (RSAP).

            The PD/GWSS Board commissioned a program review to gain a better understanding of research progress made, anticipated timelines toward achieving sustainable solutions and strategies that address Pierce’s disease (PD) in commercial vineyards, and a strategy for optimizing research activities to accelerate development of viable solutions for disease control, prevention and elimination.

            “The recommendations put forth by the RSAP give us a clear picture of what has been accomplished since the last review in 2004 and what tools the industry may have to work with in the future to control Pierce’s disease,” said CDFA Secretary A.G. Kawamura.

The RSAP, made up of six individuals representing the breadth of technology and scientific disciplines that encompass the current CDFA PD/GWSS research program was appointed by Secretary Kawamura and has since reviewed 146 research projects. Projects were assessed on whether or not they address a recommended research category, its stage in the research pipeline and timeline for providing a viable control strategy.

            According to the RSAP, significant progress in research had been made since a similar review was undertaken in 2004 by the National Academy of Sciences (NAS). Particularly noteworthy advances, as identified by the RSAP, include: identification of Xylella fastidiosa (Xf) factors that mediate virulence on grape; development of strain-specific genetic markers; potential for using transgenic rootstocks, insecticidal-based control of GWSS, epidemiology of GWSS, taxonomy and general biology of parasitoids; breeding for resistance/mapping resistance genes; and grape genomics.

            The RSAP also identified target research areas for the short-term (two to five years) and the long-term (five to 10 years). Short-term target areas include: expansion and enhancement of the GIS database and PD resistance in existing commercial grape varieties. Long-term target areas include: diffusible signal factor, transgenic expression of polygalacturonase inhibiting proteins, targeting other Xf proteins required for virulence; parasitoids; and marker assisted selection-based breeding for resistance.

            In addition to refocusing the program’s key research objectives, the RSAP also identified perceived gaps in knowledge. The RSAP recommended the further exploration of the following issues: economic analyses, the interaction of Xf with GWSS, an integrated GIS-based database and a mechanism allowing growers to quickly access current information.

            Final recommendations included the assembly of an additional group of experts to evaluate potential hurdles associated with the development of various PD control approaches and the expansion of the current research database. According to the RSAP, the utilization of the database as a universal reporting system for all PD/GWSS-related research would promote communication among researchers.

The full report and RSAP member biographies are available online from the CDFA Web site at http://cdfa.ca.gov/pdcp/Research.html. The report will be discussed at the annual PD Research Symposium, December 12 – 14, 2007.  


The PD/GWSS Board was established in July 2001 to support scientific research to find a cure for Pierce’s disease. An annual assessment paid by winegrape growers supports its research efforts.  The PD/GWSS Board also advises the California Department of Food and Agriculture on a variety of other issues pertaining to Pierce’s disease and the glassy-winged sharpshooter.

The work of the Board is underlined by the fact that Pierce’s disease has no known cure and, left unchecked, could be devastating to the grape industry and several other California crops. A study released in 2006 by the Wine Institute and the California Association of Winegrape Growers showed that the total annual economic impact of California’s winegrape industry is estimated at $51.8 billion.

California Department of Food and Agricu