August 2026

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• Response Teams Work to Prevent GWSS Spread from Nursery Shipments

• New Glassy-Winged Sharpshooter Infestation in Sacramento County

•  GWSS Control Efforts Shift North as Infestations Grow

• PD/GWSS Winegrape Assessment Holds at $1.25 for the 2026 Harvest

Response Teams Work to Prevent GWSS Spread from Nursery Shipments

GRAPEVINES

State and county agriculture officials continue working to track down the nearly 10,000 grapevines that may have carried the glassy-winged sharpshooter (GWSS) into 40 Northern California counties from a Fresno County nursery.

So far, county officials have contacted more than 3,100 customers, inspected and/or destroyed more than 2,900 plants and placed more than 2,700 additional GWSS traps. As of Aug. 18, GWSS has been found on the grapevines in 22 counties. Finds are largely eggs or young insects, though 14 adults have been found in 10 counties.

Trapping at grapevine trace-forward sites will continue through September. If funding is secured for enhanced monitoring, detection trapping could resume as early as February 2027. Routine GWSS detection trapping will continue through the fall and resume in summer 2027 as part of counties’ regular pest surveillance.

The initial response cost an estimated $3.2 million. The California Department of Food and Agriculture estimates another $8.2 million will be needed for the first 12 months of continued response work and has requested state and federal funding. The PD/GWSS Board has committed $820,000 of winegrape grower funds to help continue the response.

DESERT WILLOWS

Officials are continuing to investigate desert willow plants shipped from Texas that also carried GWSS into California. The plants reached 87 Costco stores across the state, with customers purchasing 376 plants in 18 counties. Costco has contacted nearly 300 customers to help locate the plants.

As of Aug. 11, officials had confirmed 330 GWSS egg masses on plants from these shipments. No GWSS nymphs or adults have been found in the samples, but officials did find one egg mass of broad-headed sharpshooter, another invasive insect that can spread Pierce’s disease.

CDFA and its partners are continuing to investigate the situation, and the Texas nursery cannot ship plants to California until the pest problem has been addressed.

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

New Glassy-Winged Sharpshooter Infestation in Sacramento County

A new GWSS infestation has been declared in Folsom in Sacramento County. Since June, officials have found 20 adults, but no other life stages.

Officials are investigating the extent of the infestation through trapping and visual surveys, and plan to treat properties and release biological control wasps to eliminate the pest.  

Although GWSS have been found on Sacramento County plants linked to the Fresno nursery shipment, there is also an existing infestation in neighboring El Dorado County. Eradication efforts have been underway in El Dorado Hills since October 2024.

This new infestation is especially concerning as Sacramento County is close to many Northern California wine-growing regions. The invasive pest feeds on hundreds of plants, including many used in landscaping, and spreads Pierce’s disease, which is deadly to grapevines. When it spreads to new areas, GWSS can cause major damage to the environment, agriculture and the economy.

There are currently 523 Sacramento grape production properties vulnerable to this infestation. A total of 37,173 acres of grapes, collectively valued at $167,905,000, were grown in Sacramento County in 2024.

GWSS eradication projects can take several years. The Pierce’s Disease Control Program is currently overseeing projects in five counties and has successfully eradicated 18 GWSS infestations since 2001, including two in Sacramento County in 2009.

GWSS Control Efforts Shift North as Infestations Grow

The Pierce’s Disease Control Program’s primary goal is to contain the spread of the glassy-winged sharpshooter, keeping the pest out of the state’s major winegrape-growing regions.

To stop the GWSS from spreading beyond the infested areas of Southern California and the southern San Joaquin Valley, PDCP uses nursery inspections, trapping and treatment, bulk citrus inspections, area-wide treatment programs and biological control. It also responds quickly when GWSS is identified in new areas.

PDCP currently oversees GWSS eradication projects in five counties: El Dorado, Sacramento, Santa Clara, Solano and Stanislaus. With new infestations increasing and response funding limited, the program is prioritizing these Northern California projects. It ended the Kings County eradication project and urban treatments in Fresno, Madera and Tulare counties, but will continue other GWSS prevention and control work in infested areas.

PDCP and county agricultural commissioners are also investigating several recent GWSS finds in additional counties and determining next steps. The finds are in:

• Oakley, Contra Costa County
• New Cuyama, Santa Barbara County
• Santa Clara/Cupertino, Santa Clara County
• Waterford, Stanislaus County

Eradicating a new GWSS population can take several years and cost about $3.5 million per year. Since 2021, PDCP has spent more than $10 million on multiple eradication projects, including the five currently underway. Learn more about GWSS control projects.

PD/GWSS Winegrape Assessment Holds at $1.25 for the 2026 Harvest

The PD/GWSS Board has set the 2026 winegrape assessment rate at $1.25 per $1,000 of crop value, marking the fifth consecutive year at this level.

The grower-led Board weighed the need for continued investment in vineyard protection against the serious financial pressures facing California winegrape growers.

"As growers ourselves, we understand the challenges facing the industry," said Trey Irwin, PD/GWSS Board Chair. "The Board remains committed to investing assessment funds wisely and supporting research that helps protect vineyards while being mindful of the financial pressures many growers are experiencing. We believe maintaining the current assessment rate strikes the right balance."

Assessment funds support research and response efforts focused on Pierce’s disease, glassy-winged sharpshooter, grape viruses and the insects that spread them. Since 2001, the Board has invested $62.1 million in more than 320 research projects to help protect California vineyards from pests and diseases.

cdfa.ca.gov/pdcp | pdcpinfo@cdfa.ca.gov | (916) 900-5024