economic thresholds, nor are there complete data on the effects of area wide management programs (Gleeson et al., 2004). The gaps in knowledge about prevention and cure are substantial. Given the short period of intense study, however, and the complexity of the challenges presented by PD, the insect vectors, the host plants, and the California agricultural landscape, those gaps are not unexpected.

Although most of projects funded over the past 3 years are only now beginning to yield results, current federal and state fiscal challenges are likely to reduce the amount of funding available for agricultural research, outreach, and management programs. That fiscal reality and the economic consequences of PD provide the context for the Committee on California Agricultural Research Priorities: Pierce’s disease deliberations: the need to focus priorities for research on the biology and management of the PD–GWSS problem.


The California Department of Food and Agriculture has divided the current PD–GWSS program into nine areas of basic research (Gleeson et al., 2004):

  • crop biology and ecology ($1.34 million)

  • vector basic biology ($692,000)

  • insect–plant interactions and vector population ecology ($1.09 million)

  • genetics of Xf ($930,000)

  • Xf––host plant–insect interactions ($3.2 million)

  • Xf disease epidemiology ($1.26 million)

  • vector monitoring and action thresholds ($1.38 million)

  • Xf monitoring and action thresholds ($1.56 million)

  • economics ($100,000)

The program also supports development of applied strategies for managing PD–GWSS:

  • biological control of Xf and vector ($3.0 million)

  • chemical control of Xf and vector ($3.68 million)

  • cultural, physical, and behavioral control ($435,000)

  • resistance to Xf diseases ($1.07 million)

Basic research accounts for just over half of the funding, with projects that examine interactions between the host, the insect vector, and the pathogen receiving the largest share. Most of the funding for applied research has been spent on studying chemical controls of the vector. Economics studies are noticeably under funded.

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