MONDAY, MARCH 17, 2025. BY PIERCE’S DISEASE/GLASSY-WINGED SHARPSHOOTER BOARD.
FEATURED IMAGE: Symptoms of Pierce’s Disease on a leaf. Photo by University of California.
California winegrowers should keep an eye on their mailboxes because they will vote in April on extending the Pierce’s Disease and Glassy-Winged Sharpshooter (PD/GWSS) Assessment for another five years through 2031. Results are expected in June. The annual value-based assessment on winegrapes, set at $1.25 per $1,000 of value for the past three years, powers research and solutions to fight pests, prevent disease and protect vineyards. Last conducted in 2020, the referendum passed with 78% approval.
Through the renewal of the assessment, grower’s continued commitment to the industry and government partnership, led by the statewide Pierce’s Disease Control Program, leverages funding for essential activities, including:
• Researching nine pests and diseases, as directed by the PD/GWSS Board
• Maintaining and monitoring GWSS traps
• Eradicating new GWSS infestations
• Inspecting nursery stock shipments and overseeing nursery treatments
• Controlling GWSS using area-wide management programs
• Operating a biological control program to suppress GWSS populations
The threat of pests and diseases is a constant battle for growers, but research driven by the PD/GWSS assessment and directed by the grower-led PD/GWSS Board remains the cornerstone for developing effective management and long-term solutions to Pierce’s disease, GWSS and other pests and diseases. The PD/GWSS Board ensures that industry dollars are spent on practical, relevant research aligned with growers’ needs. Having Aaron Lange of LangeTwins Family Winery & Vineyards as a Board member brings the unique concerns and needs of Lodi growers to the table.
“The PD/GWSS program is much more than critical research into Pierce’s Disease and viruses like leafroll 3. PD/GWSS funds and efforts go towards waging war against glassy-winged sharpshooter infestations in the South Valley – some as close as Fresno – and they are successfully holding them in check from moving to other grape growing regions like ours.”
– Aaron Lange, LangeTwins Family Vineyards and Winery, PD/GWSS Board Member
WHO VOTES?
Every winegrape producer who paid the 2024 assessment will receive a ballot to vote. Growers who operate multiple entities will receive separate ballots for each entity. Each ballot should be completed and returned by mail as soon as possible.
WHAT ARE THE PASSAGE REQUIREMENTS?
To pass, at least 40% of ballots must be returned. Additionally, either:
(a) at least 65% of voters, representing a majority of assessments paid, vote “yes” OR
(b) a majority of voters, representing at least 65% of assessments paid, vote “yes.”
RESEARCH AT WORK FOR YOU
The PD/GWSS Board advises the California Department of Food and Agriculture (CDFA) on using assessment funds to find solutions to winegrape pests and diseases, such as red blotch, leafroll and mealybugs.
Thanks to the ongoing support of California’s winegrowers, the PD/GWSS Board has accelerated focused, groundbreaking research to advance knowledge, improve management practices and rapidly respond to emerging threats.
Since 2001, the PD/GWSS Board has invested $57.7 million in 298 research projects, with $14.2 million dedicated to viruses and vectors research. The PD/GWSS Board currently supports 35 multi-year projects and will evaluate new research proposals at its April meetings.
Field trials of biopesticides for managing Pierce’s disease.
Pierce’s Disease Research Highlights
- Filling Pierce’s disease and GWSS knowledge gaps
- Studying how Pierce’s disease spreads in vineyards
- Investigating genetic resistance to Pierce’s disease
- Developing and testing Pierce’s disease-resistant winegrapes
- Evaluating wine quality from Pierce’s disease-resistant grapes
- Using biological controls to protect vineyards
- Managing GWSS resistance to insecticides
Breeding Pierce’s disease-resistant winegrapes.
Other Pest & Disease Research Highlights
- Helping to eradicate the European grapevine moth
- Identifying insect vectors of grapevine viruses
- Studying how grapevine viruses spread
- Understanding virus impacts on vine health and grape quality
- Developing management strategies for brown marmorated stink bugs and mealybugs
- Exploring resistant grape cultivars and rootstocks for vine mealybug
- Grapevine virus outreach projects, such as the Lodi Winegrape Commission’s book What Every Winegrower Should Know: Viruses
Processing samples for virus testing at Foundation Plant Services.
Learn more about PD/GWSS Board-funded research HERE.
QUESTIONS?
If you have questions, contact the CDFA Marketing Branch at 916.900.5018, email Miranda Townsend at Miranda.Townsend@cdfa.ca.gov or email Denise Sanchas at Denise.Sanchas@cdfa.ca.gov.
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