Attention Stanislaus Sprout readers!
An invasive insect called the glassy-winged sharpshooter (GWSS) has been found on grapevine shipments sold at select Costco locations in Northern California between April 21 and May 19, 2026.
If you or someone you know has recently purchase a grape plant at Costco please read this article to know what to do, what NOT to do, and help spread the word to limit the spread of the insect and the disease it carries.
GWSS is an invasive insect pest that spreads a bacterium which causes a fatal grapevine disease (called Pierce’s disease), potentially affecting 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.
State and local agricultural officials identified the issue quickly and immediately began response and containment efforts. The infested nursery stock came from a 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.
Costco has been cooperative in notifying customers, issuing refunds and helping connect purchasers with local county agricultural commissioner offices for inspection and disposal guidance.
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Officials are still evaluating additional suspect samples from several other counties, including:
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WHAT TO DO IF YOU PURCHASED A PLANT
People who purchased a grapevine from Costco in an affected county between April 21 and May 19, should 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(s) in 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:
- An agricultural inspector will come to look at the plant and other nearby host plants.
- If inspectors find GWSS on the grapevine, they will safely remove and dispose of the plant.
- GWSS monitoring traps may be placed on the property.
- Please cooperate with local inspectors if they need to investigate plants on your property.
HOW CAN YOU HELP?
Please help spread the word. Share this notice on your social media, local networks, or simple talk to your neighbors and friends.
For more information visit the California Department of Food and Agriculture.
Reblogged from Pests in the Urban Landscape