California Ag Network

Tag: Glassy Winged Sharpshooter

  • Funding Committed to Fight Pierce’s Disease

    The Consolidated Central Valley Table Grape Pest and Disease Control District Board of Directors authorized the use of up to $1.7 million in district reactionary funds, generated through the California table grape industry, to support CDFA activities related to the prevention and control of Pierce’s Disease (PD) and the Glassy-Winged Sharpshooter (GWSS).

    The action was taken during the district’s board of directors meeting on Friday, August 21, 2026, in response to an approximately $1.7 million funding shortfall associated with current PD/GWSS program activities.

    The district recognizes continued GWSS surveillance, treatment, and suppression as critical to limiting the spread of Pierce’s Disease and protecting California’s table grape, wine grape and raisin industries. Since there is currently no cure for Pierce’s disease, preventing the movement of the disease and controlling populations of GWSS remain essential to protecting California vineyards.

    Background

    The Consolidated Central Valley Table Grape Pest and Disease Control District was formed pursuant to Article 8.7 of Chapter 9 of Division 4 of the California Food and Agricultural Code.

    Under California Food and Agricultural Code Section 6047.87, the district is authorized to take actions necessary to control, eradicate, remove, or prevent the spread of GWSS, Pierce’s Disease and other designated pests and diseases injurious to table grapes. GWSS presents a significant threat because it can spread the bacterium that causes Pierce’s disease as it feeds on grapevines.

    Historically, USDA and CDFA have provided funding for the GWSS Area-Wide Treatment Program. Due to federal and state funding shortfalls, the funding toward the GWSS program has been cut year-over-year. The district’s board of directors is providing emergency industry funding to prevent disruption of the program while longer-term state and federal funding solutions are pursued.

    Protecting Kern and Tulare Counties

    GWSS and Pierce’s Disease do not recognize county, crop, or district boundaries. A

    coordinated, area-wide approach to surveillance and treatment is critical to reducing GWSS populations and limiting the potential movement of the pest into vineyards and other agricultural areas.

    Citrus plays a particularly important role in GWSS management because citrus trees serve as a primary year-round host for the pest. Area-wide programs use trapping and monitoring to identify areas with elevated GWSS populations and coordinate treatments in citrus and other host areas when necessary.

    The funding commitment from the district will help support continued CDFA-coordinated PD/GWSS activities, including area-wide efforts that provide resources for eligible citrus growers to conduct approved treatments designed to suppress GWSS populations. These activities complement trapping, monitoring, and other preventative measures intended to reduce the movement of GWSS and protect nearby vineyards.

    By committing up to $1.7 million from accumulated district reactionary funds, the board is

    investing industry-generated funds directly into efforts intended to protect table grape

    growers. For growers in Kern and Tulare counties, there will be no assessment change.

    The district remains committed to working collaboratively with CDFA, county agricultural

    commissioners, growers and other agricultural partners to protect California’s grape industry from Pierce’s Disease and Glassy-Winged Sharpshooter.

    For additional information, please contact the Consolidated Central Valley Table Grape Pest and Disease Control District at 559-210-0118. — Story contributed by the Consolidated Central Valley Table Grape Pest and Disease Control District

  • This Week In Ag

    This Week in Ag: Five stories you need to know from across California agriculture.

    This week, we’re covering new funding to stop the spread of glassy-winged sharpshooter, a potential new tool for fighting navel orangeworm, free business training for producers, a USDA trade mission to Singapore, and a $2 million investment aimed at helping the tree nut industry overcome trade barriers.

    Stay informed on the issues and opportunities shaping California agriculture.

    For more news impacting the California ag industry, follow California Ag Network.

  • Wine Grape Industry Commits Additional Funding to Stop GWSS

    To stop the glassy-winged sharpshooter from spreading a fatal grapevine disease into Northern California, the Pierce’s Disease and Glassy-Winged Sharpshooter (PD/GWSS) Board at the California Department of Food and Agriculture committed $820,000 to the ongoing emergency response.

    Preventing the glassy-winged sharpshooter from becoming established in new areas protects winegrapes and other agricultural and landscape plants. California’s wine industry generates about $73 billion in annual economic activity and supports more than 422,000 jobs statewide. A 2025 economic study estimated that if glassy-winged sharpshooters spread unchecked, outbreaks of Pierce’s disease could cost winegrape growers an additional $56 million a year in lost production and vine replacement.

    Since May, county agriculture officials have been tracking down nearly 10,000 grapevines from a Fresno nursery that may have carried the invasive pest into 40 counties. The Board’s special emergency funding is intended to support those efforts. Officials have contacted more than 3,100 customers who purchased the grapevines, inspected and/or destroyed more than 2,900 plants and set more than 2,700 additional insect traps.

    Glassy-winged sharpshooters have been found on customer plants in 23 counties. Inspections and trapping must continue for at least three years to track if the pest spreads beyond customers’ properties.

    “California’s winegrape industry is facing some of the hardest economic times in a generation, but we recognize what is at stake if this destructive pest becomes established in Northern California,” said Board chair Trey Irwin. “Putting $820,000 from the Board’s limited reserves toward this effort is a major commitment for our industry and shows how seriously we’re taking this threat.”

    The funding comes from assessments paid by California winegrape growers to support pest and disease research and prevention. Since 2001, the Board has invested $99 million in research, outreach, prevention and control for Pierce’s disease, grapevine viruses and the insects that spread them.

    “It is important that we continue with inspections and trapping to closely monitor the situation,” said Michelle Pham, response lead with the CDFA Pierce’s Disease Control Program. “This effort depends on close coordination among growers and county, state and federal agencies. For 25 years, that partnership has helped keep the glassy-winged sharpshooter from spreading throughout California.”

    People who suspect they have found a glassy-winged sharpshooter should contact their local agricultural commissioner’s office (bit.ly/CountyAg). For pictures of the pest and for more information, visit bit.ly/GWSS-Costco.

  • CAWG Presses Federal Agenda

    The California Association of Winegrape Growers (CAWG) led a delegation of growers to Washington, D.C., June 1-3 to advance a federal policy agenda aimed at restoring competitiveness, strengthening risk management tools and supporting the long-term viability of California vineyards.

    Over three days, CAWG representatives met with more than 20 offices, including those of California’s two U.S. senators and eight members of the U.S. House of Representatives, along with senior staff on the Senate Agriculture and Finance Committees and the House Agriculture Committee. The delegation also met with officials from the Office of the U.S. Trade Representative, the White House Office of Public Liaison, the USDA Risk Management Agency and USDA’s Research, Education and Economics mission area.

    Growers advocated for a broad set of federal priorities, including closing a narrow excise tax loophole that subsidizes imported bulk wine and addressing a labeling gap that allows foreign wine to be blended into bottles labeled “American.”

    The delegation also engaged in a broader trade discussion about the competitive disadvantages California growers face from subsidized and cheaper foreign wine, and continued to push for closing a Canadian classification gap that allows non-grape, bulk “wine” to enter the U.S. classified and taxed as wine. Growers also pressed for improvements to federal crop insurance programs, both emergency response and sustained funding for recent glassy-winged sharpshooter outbreaks in California, protection of critical USDA crush and acreage reports, and continued investment in wildfire smoke research.

    “California winegrape growers are facing one of the most difficult periods in recent history, but there are tangible steps policymakers can take to strengthen the industry’s future,” said CAWG President Natalie Collins. “We’re pursuing every available avenue to ensure growers can compete on a level playing field and that federal policies support domestic agriculture, strengthen rural communities, and enhance the competitiveness of California wine.”

    The delegation emphasized that California winegrape growers have endured years of declining crush volumes, contract cancellations, vineyard removals, and historically high levels of unharvested fruit, placing significant economic strain on farming families, agricultural workers and rural communities across the state.

    “There’s no substitute for growers sitting across the table from policymakers and explaining how these issues affect their operations, employees, and communities,” said Tom Merwin of Merwin Vineyards and chairman of CAWG’s Federal Issues Committee. “At this critical time for growers, these conversations matter more than ever.”

    — Story Contributed by the California Association of Winegrape Growers

  • CDFA Urges Immediate Reporting of Grapevines Purchased at Costco

    The CDFA is urging anyone who purchased grapevines from Costco stores in Northern California between April 21 and May 21 to contact their local agricultural commissioner after an invasive pest was discovered among the 13,000 vines shipped during that period.

    Grapevines from a Fresno nursery shipped to California Costco stores in April and May were found to be carrying the glassy-winged sharpshooter (GWSS), an insect capable of spreading a potentially lethal vine disease.

    On May 19, the first glassy-winged sharpshooter was detected on vines sold at the warehouse retailer, triggering an immediate and widespread containment effort by CDFA, agricultural commissioners and winegrape growers throughout Northern California. Officials are responding to public reports, conducting inspections and public outreach and trapping near stores and locations where purchased vines were taken. They are also ensuring that potentially infested plants are safely contained and disposed of.

    In addition to destroying infested stock still in Costco warehouses, CDFA is working with agricultural commissioners and conducting public outreach to locate vines sold to consumers across 24 counties, as well as neighboring at-risk counties.

    “While many vines have been intercepted and destroyed, locating the thousands that may still be in customers’ hands remains our top priority,” said California Ag Secretary Karen Ross. “Anyone who purchased these vines should contact their local agricultural commissioner immediately.”

    Costco is offering a full refund to anyone who purchased these vines. Customers do not need to return the vines to receive a refund.

    To prevent the potential spread of the pest, CDFA officials urge customers to:

    •Immediately contact your county agricultural commissioner

    •Keep the plant in its original pot or container and away from other plants

    •If possible, place the plant inside two trash bags, one inside the other, and seal them closed

    •Do not place the plant in the trash or compost bin

    •An agricultural inspector will come, inspect the vine for GWSS and — if necessary — remove and dispose of the vine

    Winegrapes are one of California’s largest cash crops, generating approximately $73 billion annually in economic activity and supporting more than 422,000 jobs statewide. A 2025 economic study estimated that Pierce’s disease, which is spread by the glassy-winged sharpshooter, could cost California approximately $166 million annually if left unchecked.

    California first recognized the full threat of the glassy-winged sharpshooter in 1999, when a major Pierce’s disease outbreak in the Temecula Valley led to the destruction of more than 300 acres of vineyards. Winegrape growers quickly responded by working with the CDFA to create the Pierce’s Disease Glassy-Winged Sharpshooter Board to control the pest and find solutions to the disease it carries. The program has successfully contained GWSS for over 25 years. Visit cdfa.ca.gov/pdcp/PD_GWSS_Board.html. — Story Contributed by the California PD/GWSS Board

  • Glassy-Winged Sharpshooter Outbreak in Turlock has Regional Grape Growers on High Alert

    A Glassy-Winged Sharpshooter find in Turlock back in August 2024 has led to an expanding quarantine in Stanislaus County. The primary vector for the grapevine-killing Pierce’s Disease, this insect pest is a top concern for the regional grape industry and the Stanislaus County Ag Department. At Malcolm Media’s Tree & Vine Expo in Turlock and in an interview with Matthew Malcolm on California Ag Network, Stanislaus County Ag Commissioner Linda Pinfold shared the details of the quarantine and their efforts with the community in eradicating this invasive pest from the county. Watch this brief interview and read more about it in the January issue of American Vineyard Magazine.

  • Why this Grape Grower Urges a Yes Vote on the Pierce’s Disease Glassy-Winged Sharpshooter Referendum

    California wine grape growers have the opportunity to vote on whether to continue assessments to support the Pierce’s Disease Glassy-Winged Sharpshooter (PD/GWSS) Board. Ballots are being sent in the mail this month. Administered by CDFA and led by the wine grape industry for the last 25 years, this program funds research and activities to lessen the impact of threatening vineyard pests & diseases. Watch this brief interview with Lodi wine grape grower Aaron Lange as he shares with Matthew Malcolm on California Ag Network why he is voting “yes” on the referendum and explains what the Board has been working on that he finds so critical to the future of the industry.

    Please thank this video’s sponsor SIPCAM AGRO USA for their industry support.

  • Pierce’s Disease Investment Saves Wine Grape Growers $56M Annually

    According to a new economic impact study, the California Department of Food and Agriculture’s Pierce’s disease (PD) and glassy-winged sharpshooter (GWSS) prevention, control and research efforts save California winegrape growers $56 million annually by reducing losses from the fatal grapevine disease. Without the program’s efforts, growers’ losses would more than double from $48 million to $104 million. The study found that if GWSS spread unchecked, outbreaks of PD could cost winegrape growers an additional $56 million a year in lost production and vine replacement.

    The Costs of Pierce’s Disease in the California Grape and Wine Industry

    “This study highlights the serious threat Pierce’s disease and the glassy-winged sharpshooter pose to our industry and reinforces the importance of grower-funded research,” said Randy Heinzen, a Paso Robles winegrape grower on the Pierce’s Disease and Glassy-Winged Sharpshooter Board. “The public-private partnership led by the Pierce’s Disease Control Program is vital, allowing grower assessment funds to drive research that improves pest and disease management and to develop practical, sustainable solutions for the long-term viability of our industry.”

    The unique funding partnership the winegrape industry forged between growers, the state and federal government and industry fuels the essential research and control operations that have significantly blunted the most severe impacts of PD and GWSS. Even with these efforts, PD still costs an estimated $110 million annually in California, including $45 million for control, prevention and research, $48 million in lost winegrape production and vine replacement and $17 million in lost table and raisin grape production and vine replacement. Without these critical programs, the industry’s losses in production and vine replacement would be even higher, putting greater financial strain on growers and threatening the long-term stability of California’s vineyards.

    With industry and government support keeping PD and GWSS in check, grower-funded research continues to drive advancements in pest and disease management while supporting field trials for promising solutions. According to the study’s authors, the economic burden of PD and GWSS could decrease as this research yields practical, vineyard-ready innovations.

  • Harnessing the Power of Natural Volatile Compounds in Grapevines that Thwart Sharpshooters

    Grapevines have a natural defense mechanism against Glassy-winged sharpshooter, a notorious vector for Pierce’s disease, that researchers are trying to learn more about. Watch this brief interview with Julie Pedraza from the Fresno State Viticulture & Enology Research Center and read more about it n American Vineyard Magazine.

    Please thank this video’s sponsor Suterra for their industry support.

  • Growers Petition for a Sonoma County Winegrape Pest & Disease Control District

    Over the course of more than 18 months, a group of viticulturists and vineyard owners have been working together to research both the benefits of, and the process for establishing a Winegrape Pest and Disease Control District in Sonoma County. They have engaged in research and discussed an effort with elected and appointed Sonoma County Officials, University of California Cooperative Extension & UC-ANR, Napa County Agricultural Commissioner’s Office, Napa County Winegrape Pest and Disease Control District Board of Directors, State Legislators, and other Pest Control Districts throughout California.

    The California Winegrape Pest and Disease Control District Law enables owners of wine grape acreage within Sonoma County to petition the Sonoma County Board of Supervisors to acknowledge and establish a Wine Grape Pest and Disease Control District. The Sonoma County Winegrape Pest & Disease Control District Coalition is organizing this petition effort for the Sonoma County Board of Supervisors.

    Included is a petition of support and frequently asked questions about the functionality of the Special District. Please take a moment to read through the benefits of such a district, visit https://sonomacountypcd.org, review what Napa’s WGPDCD has been working on for the last 20 years, and give your support in petitioning the Board of Supervisors to allow the formation of one in Sonoma County, which would allow collaboration in ongoing pest control efforts, not only with each other, but with neighboring districts to form area wide protection from harmful pests.

    Coalition member and Grower Relations Manager at Jordan Vineyard & Winery Dana Grande shared, “I have been a part of the group working on this for the last 24 months. A Pest and Disease Control District (PCD) for Sonoma County winegrapes is something that I have thought we needed for a very long time. When I heard about the opportunity to assist in the exploratory committee, I jumped in… Ultimately, the dollars spent will be up to the discretion of the PCD Board, but we envisioned that those funds would be used for local research, augmenting pest monitoring, pest mitigation and exclusion, and mobilization of efforts should an exotic pest be discovered in our County. Our neighbors in Napa County have had a PCD for the last 20 years. We can look to their model to envision what might be funded in Sonoma County.

    Bryon Sheets from Doc’s Ranch Vineyard added, “With all the challenges us growers face, it just makes sense to have this additional community resource to help us fight the important battle against invasive pests.”

    Karina Maher, a grower and doctor in Glen Ellen shared her support of the district as well, quoting Benjamin Franklin, that “An ounce of prevention is worth a pound of cure.” She continued, “As a pediatrician, I know this to be true for human health. Similarly, the time to prevent and recognize wine grape pest and disease infestations is before they get out of control. The Winegrape Pest and Disease Control District in Sonoma County will help do just that. The time is now.”

    Sonoma County growers are invited to Download and sign the petition HERE. “Please return your completed petition to us as soon as possible,” requests Jason Saling, grower and leader of the Sonoma County Winegrape Pest Control District Coalition. ” Your support is appreciated. It is through this effort that winegrowers of Sonoma County can secure and protect their agricultural interests now and into the future.”

    Don’t hesitate to reach out to Jason Saling at 707-328-5290 or SonomaCountyPCD@gmail.com for more information.

    FREQUENTLY ASKED QUESTIONS

    What is a Winegrape Pest & Disease Control District?

    A Pest & Disease Control District (PCD) is a grower funded, grower run Board serving the needs and priorities of the agricultural commodity that funds it.

    How is a PCD funded?

    As defined in the California Food and Ag Code, Section 6200-6290, funding is generated by a minor per planted wine grape acre assessment. The assessment is collected annually by the County Assessor as part of property taxes, and 100% of those funds are placed into a trust account specific for Pest & Disease Control District. The assessment is capped by State law at $5.00 per planted acre of wine grapes.

    Who forms the PCD Board? How do Growers/Owners know where the assessment dollars are spent?

    Wine grape landowners or their duly authorized representatives serve on the PCD Board. Meetings of the Board must comply with the Brown Act. Meetings are open to the public and agendas are posted ahead of the meeting. Agenda and non-agenda items can be addressed by growers at each meeting. Budgets are formed annually and formally presented at Board meetings. Directors, appointed by the Board of Supervisors serve a three-year term. The district is re-authorized by the BOS for 5-year terms.

    Why do we need a PCD now, can’t we wait until we discover a new pest threat in our vineyards?

    No. A PCD serves to manage both established pests, and works to avoid the establishment of new pest threats. A PCD is funded for a cohesive and coordinated system for detection and eradication. Without a PCD, individual expenses could be very high, and isolated eradication efforts may not banish the pest from our industry. Long-term effects could include increased costs for insecticides, increased labor costs for monitoring, establishment of new pest control compliance agreements, organic growers losing certification due to use of non-certifiable insecticides, fruit quality issues, and tarping/monitoring grape loads at harvest.

    A Sonoma County PCD will serve to promote and protect the long-term sustainability of our industry by ensuring that our integrated pest management activity remains resilient, protecting both our agricultural interests and our natural resources.

    How does a Sonoma County Wine Grape PCD add value to my vineyard?

    Over the last 20 years, Sonoma County wine grape growers have seen the introduction and establishment of Vine Mealybug (VMB.) Additionally, Light-Brown Apple Moth (LBAM), Virginia Creeper Leafhopper, Glassy-winged Sharpshooter, and European Grapevine Moth (EGVM) have all threatened the integrity of wine grape production in the County.

    A PCD will ensure that early activities for eradication of an invasive pest will be coordinated and can use funds to ensure that those costs don’t fall squarely on individual landowners.

    The PCD will:

    • – Establish a pool of funding dedicated solely for early detection, monitoring, and mitigation of wine grape pests and diseases

    • – Create an open forum and dedicated grower board to respond to grower / owner input to determine areas of greatest need, focusing on localized research and education/outreach

    • – Coordinate with UCCE / UC ANR, Sonoma County Ag Commissioner to leverage funding and labor resources

    • – Coordinate with neighboring regions, i.e. Napa, Mendocino, Lake, Marin and Solano Counties to extend a buffer zone around Sonoma County’s high value wine growing region

    • – Communicate, coordinate, and cooperate in establishing local research priorities to the UCCE / UCANR

    • – Establish a Board with a County level voice for requesting co-funding as required from Sonoma County BOS, and State and Federal Grant opportunities.

      Does Napa County have a Pest and Disease Control District?

      Yes. On January 4, 2022, the Napa County BOS renewed the NCPCD for its fifth consecutive 5-year term since its inception in 2002, when GWSS was first identified as an impending threat to the industry. The District was in place and ready when European Grapevine Moth was discovered, and quickly mobilized trapping efforts to successfully delimit and restrict the migration, and, within two years, eradicate the pest by working in tandem with and resources provided by the UCCE, Napa County Ag Commissioner, and CDFA.

      Additional examples of work funded by the NCPCD:

    – Vine Mealybug mapping identifying hotspots and published a GIS web map,
    o Public, Grower, and Field worker training and education on VMB,
    o Coordinated mating disruption to decrease insect population, and
    o Funded and Coordinated Anagyrus wasp release to augment biological control;

    – Glassy-Winged Sharpshooter (GWSS) –
    o Supplementing funding to ensure that 100% of nursery shipments are inspected,
    o Increasing trapping and seasonal monitoring now that GWSS is established in Solano County

    – Pest Identification workshops for all manner of pests, new and exotic threats to the industry

    But our Agricultural Commissioner already does plant inspections. Why do we need a PCD?

    The Sonoma County Department of Agriculture administers exclusion programs to keep invasive and injurious pests out of Sonoma County. In 2020, staff inspected 1069 nursery stock shipments for GWSS. Additionally, they deployed trap programs for other invasive insects and those 6531 traps were serviced 52,721 times. As robust as our AC’s programs are, their priorities are directed at specific pest species and ratings as defined by CDFA. As State and County funding for specific pest management/exclusion programs diminishes over time, PCD’s can step in to further fund prevention and monitoring for a wine grape specific pest, disease, or research not addressed by State or County priority.