The Crush - February 2020 - 1

Volume 47 Issue 2 February 2020


Pierce's Disease Assessment Referendum Coming
By Ted Rieger
California winegrape growers will vote this spring on whether
or not to continue the assessment they have paid annually since
2001 to fund the California Department of Food and Agriculture's
(CDFA) Pierce's Disease/Glassy-winged Sharpshooter (PD/
GWSS) Board's programs.
The 15-member board advises CDFA on the use of assessment
funds for research and outreach designed to prevent grapevine
losses and control the spread of PD and its primary vector, the
glassy-winged sharpshooter. Approval of the referendum will
extend the assessment and board five years, until March 1, 2026.
Legislation has required grape growers to vote to continue
the assessment every five years, which they have previously
done in 2005, 2010 and 2015. Legislation authorizing this year's
referendum (SB 449) was enacted in 2019 and supported by
CAWG, Family Winemakers of California and Wine Institute.
When the invasive GWSS was identified in the late 1990s as an
aggressive new vector of PD that rapidly killed hundreds of
acres of vineyards in the Temecula region of Riverside County,
little was known about the vector or the disease, caused by the
bacterium Xylella fastidiosa.
The PD/GWSS Board has invested $45.4 million since 2001 for
research and outreach, with $34.3 million specifically for PD
and GWSS research that has provided better understanding
and knowledge about the GWSS as a vector, and about
the mechanisms of disease development and resistance in
grapevines. This research has enabled the development of new
PD-resistant grapevine cultivars and promising new
methods and materials to prevent and
combat PD.

The Pierce's Disease Control Program's mission is to minimize the impact of
Pierce's disease and its vectors in California. Photo: University of California

CAWG member Steve McIntyre of Monterey Pacific Vineyards
serves on the PD/GWSS Board and chairs the Research Screening
Committee. "In just 20 years, the research supported by the board
has built a strong foundation of knowledge from which several
solutions are being developed and commercialized against
Pierce's disease, a threat that could have ruined our livelihoods,"
he said. "Likewise, our investments in research on other pests
and diseases will help us learn how to manage these other
Five new traditionally-bred winegrape varieties with PDresistant genes - that range from 94 to 97 percent Vitis vinifera
parentage - were developed by Dr. Andy Walker, viticulture
professor at the University of California, Davis (UCD). They are
expected to be available from the UCD Foundation Plant Services
this year. Additional sources and mechanisms of PD resistance
are being studied with the goal of breeding grapevines with
multiple forms of genetic resistance for commercial use in the

The Crush - February 2020

Table of Contents for the Digital Edition of The Crush - February 2020

The Crush - February 2020 - 1
The Crush - February 2020 - 2
The Crush - February 2020 - 3
The Crush - February 2020 - 4
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The Crush - February 2020 - 6
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