Purchased a Grapevine at Costco? Important GWSS Information
Last updated: May 27, 2026
The California Department of Food and Agriculture (CDFA) is responding after invasive glassy-winged sharpshooter (GWSS) insects were found on shipments of grapevines sold at select Costco locations in Northern California between April 21 and May 19.
GWSS is an invasive insect pest that spreads the bacterium that causes Pierce’s disease, a fatal grapevine disease that threatens California vineyards. The pest can also damage citrus trees, landscape plants and other crops. Early detection and rapid response are critical to preventing the pest from spreading further.
If you purchased a grapevine from Costco in an affected county during that timeframe, contact your local County Agricultural Commissioner's Office right away.
What To Do If You Purchased a Plant
If you purchased a grapevine from Costco in an affected county between April 21 and May 19, take the following steps:
Isolate the Plant
- Keep the plant in its original pot or container and away from other plants.
- Do not put the plant in the ground if you have not already done so.
- If possible, place the plant inside two trash bags, one inside the other, and seal them closed.
- Do not return, transport or relocate the plant.
- Do not place the plant in the trash or compost bin.
Contact Your Local County Agricultural Commissioner’s Office Right Away
Find your County Agricultural Commissioner
- An agricultural inspector will come to examine the plant and nearby host plants.
- If inspectors find GWSS on the grapevine, they will safely remove and dispose of the plant.
- GWSS monitoring traps may also be placed on or near the property.
Affected Counties
Confirmed GWSS Detections
- Alameda or call 510-670-5232
- Marin or call 415-473-6700
- Placer or call 530-889-7372
- Sacramento916-875-6603
- San Mateo or call 650-363-4700
- Solano or call 707-784-1310
- Stanislaus or call 209-525-4730
- Yolo or call 530-666-8140
Additional Counties Under Evaluation
Officials are still evaluating suspect samples from:
- Butte or call 530-552-4100
- Contra Costa or call 925-608-6600
- Humboldt or call 707-441-5260
- Merced or call 209-385-7431
- Napa or call 707-253-4357
- Sonoma or call 707-565-2371
Response and Containment Efforts
The Pierce’s Disease Control Program, county agricultural commissioners and Costco are actively responding to the situation. Early detection and rapid response are critical to preventing the pest from spreading further and protecting California agriculture.
State and local agricultural officials identified the issue quickly and immediately began response and containment efforts. The infested nursery stock came from Burchell Nursery in Fresno, and Fresno County Agricultural Commissioner staff and CDFA personnel have been working on-site since May 19 to stop shipments, investigate the situation and determine corrective actions.
County agricultural commissioners in affected areas are conducting inspections, responding to public reports, coordinating trapping efforts and helping ensure potentially infested plants are safely contained and disposed of.
Costco has been working cooperatively with CDFA to notify customers, issue refunds and help connect purchasers with local county agricultural commissioner offices for inspection and disposal guidance.