06/03/2026
The Tuolumne County Agricultural Commissioner is asking the community for help after a nonnative, invasive insect, the glassy-winged sharpshooter (GWSS), was recently found on Burchell Nursery grapevines, citrus, and fruit trees delivered to Costco stores across California.
GWSS can spread Pierce’s disease, a bacterial infection that can significantly impact vineyard production, be fatal to grapevines, and can attack hundreds of plant species, including ornamental species used in landscaping. Costco took immediate action upon learning of the infestation and has been a cooperative partner with County Agricultural Commissioners. Although Costco directly
contacted members who purchased plants, hundreds of potentially infested plants had already been sold.
No Costco store locations are in Tuolumne County; however, it is possible infested plant material purchased in neighboring counties was transported here. Early detection and containment are critical to protecting Tuolumne County and California’s agricultural resources.
If you purchased a grapevine, citrus tree, or other fruit tree at a neighboring Costco location between April 21 and May 21, 2026, please:
• Keep the plant isolated in its original pot or container.
• If possible, place the plant(s) in two secured trash bags, one inside the other, and seal them closed.
• Do not place the plant in the trash or a compost bin.
• Immediately contact the Tuolumne County Agricultural Commissioner’s Office at:
(209)533-5691 -or- [email protected]
• An agricultural inspector will be dispatched to examine the plants and nearby host plants.
• As a precautionary measure, GWSS monitoring traps may be placed on the property.
For more information, visit the California Department of Food and Agriculture.
