Grower Alert: Glassy-Winged Sharpshooter Detected on Grapevines Sold at Napa Costco

Between April 21 and May 26, 2026, the Napa Costco Wholesale location received multiple shipments totalling 220 grapevines from Burchell Nursery, Inc. in Fresno County. All life stages of GWSS have been detected on plants from these shipments across multiple California counties, and one GWSS egg mass was found among the Napa shipment. Of the 220 grapevines delivered, 157 remain unaccounted for and may be in the possession of community members who purchased them this spring.

GWSS is a serious invasive pest that spreads Pierce's disease, a bacterial infection that is frequently fatal to grapevines and can also damage citrus, almond, and ornamental plants. Early detection and rapid response are essential to protecting Napa Valley's vineyards and agricultural resources.

If you or anyone you know purchased a grapevine, citrus tree, or other fruit tree at Napa Costco (or a neighboring Costco location) in April or May, please take the following steps immediately:

• Keep the plant isolated in its original pot or container. Do not plant it if you have not already done so.​
• If possible, place the plant in two secured trash bags, sealed closed.
• Do not return, transport, relocate, trash, or compost the plant.
• Contact the Napa County Agricultural Commissioner's Office at 707-253-4357 or [email protected]. An inspector will be dispatched the same day.

For identification tips and photos, visit BUGSPOT.ORG or the California Department of Food and Agriculture website. The attached flyer also includes helpful images of what GWSS adults, nymphs, and egg masses look like.
We know our growers are the first and best line of defense for Napa Valley agriculture. Please share this alert widely with neighbors, colleagues, and anyone in your network who may have purchased plants at Costco this spring. Together, we can keep our vineyards protected.

Identifying the glassy-winged sharpshooter

read more