If you have any connection to the Northern California wine industry, you know that glassy-winged sharpshooters (GWSS) were found on grapevines sold at Costco locations in Northern California between April 21 and May 21 of this year. The most recent press release from the California Department of Food and Agriculture (CDFA) is available here.
This is a serious development. These tiny leafhoppers efficiently spread the bacterium Xylella fastidiosa, which is deadly to grapevines, as well as citrus, landscape plants, and many other plant species. The bacterium invades the plant’s xylem (water transport system), is fatal to the plant, and has no known cure. When it infects grapevines, it is called Pierce’s Disease.
If you or someone you know purchased a grapevine, citrus tree, or other fruit tree from a Costco in one of the 24 affected counties (consult the CDFA’s alert page for the county list), follow the instructions from the CDFA, available here, and contact your local County Agricultural Commissioner’s Office promptly. Early detection and rapid response are critical to prevent further spread.
There are online resources to help identify GWSS in its various life stages. However, especially if you live in a wine-producing region, suspected GWSS should be reported promptly to your local County Agricultural Commissioner rather than handled individually, and California has a robust program in place to keep GWSS out of vineyards.
With that in mind, this is an opportune time to highlight the legal framework California has maintained since 2000 to combat this risk to the wine industry, the public–private collaboration that has mitigated past outbreaks, and the tools that enable an effective response when incidents like the recent Costco breach occur.
California’s Pierce’s Disease Control Program (PDCP)
California established the Pierce’s Disease Control Program (PDCP) by legislation (SB 671) signed into law in May 2000, following widespread grapevine deaths in Southern California during the summer of 1999. (Source)
PDCP’s mission is to prevent and contain GWSS and Pierce’s Disease through coordinated statewide and county efforts, including diagnostics, biological control, and research. PDCP brings together CDFA and USDA personnel; County Agricultural Commissioners; growers and wineries represented on the Pierce’s Disease and Glassy-winged Sharpshooter (PD/GWSS) Board; vineyard managers; universities and other researchers; and the nursery and citrus industries. The program is led by a statewide coordinator and supported by staff throughout California. Counties carry out local activities under county work plans submitted to CDFA for approval. PDCP is funded by USDA Animal and Plant Health Inspection Service (APHIS), an assessment on California winegrape growers, and, at times, the State General Fund.
PD/GWSS Board and the Assessment Fund
Assembly Bill 1394 (July 2001) established an annual, value-based assessment on crushed grapes to fund PD/GWSS research and related activities, and also established the PD/GWSS Board of representatives from the winegrape industry to advise the CDFA Secretary on use of the funds raised by the assessment. The funds primarily support research on Pierce’s Disease, as well as other pests and diseases that affect vineyards.
The grower assessment is currently $1.25 for every $1,000 of the value of grapes delivered for crushing, and it is owed entirely by the grape grower. Although the grower bears the cost, the purchaser of the grapes is responsible for collecting the assessment and remitting it to CDFA, with payment due by January 31 each year for the previous year’s harvest. In practice, many purchasers withhold the assessment from amounts otherwise payable to the grower, while others may choose to absorb the cost. To avoid confusion, grape purchase agreements often include a clause authorizing the purchaser to withhold the assessment from grower payments and remit it to CDFA. Processors crushing under 100 tons are not exempt from these requirements.
Every five years, grape growers vote on whether to continue the assessment. In the most recent referendum, 76.56% of eligible grape growers voted in favor, extending the program through 2031. The next vote is scheduled for Spring 2030, and ballots will be sent to every producer who paid the 2029 assessment.
Elena Moreno is an Associate Attorney in DP&F’s Business group. If you have legal questions about this topic or would like assistance with a grape purchase agreement, please contact us.