California Agricultural Commissioners Launch Emergency Response to Contain Dangerous Plant Pest

Public urged to report and safely surrender potentially infested grapevines and citrus trees purchased at Northern California Costco locations

Sacramento, CA – Agricultural Commissioners in several California counties have launched emergency efforts to identify nursery plants purchased at Northern California Costco Wholesale locations that may be infested with the glassy-winged sharpshooter — a destructive invasive pest that poses an immediate threat to the state’s grape and tree fruit industries.

“Controlling the spread of this pest is the top priority for Agricultural Commissioners across the state,” said Lindsey Carter, Executive Director of the California Agricultural Commissioners and Sealers Association (CACASA), which represents Agricultural Commissioners in all 58 California counties. “Agricultural Commissioners in all affected counties are increasing inspections within their counties to address the spread and working closely with the public to locate, remove, and safely destroy infested plants before the pest can become established.”

Counties with Costco locations suspected to have received shipments of potentially infested nursery plants include: Alameda, Butte, Contra Costa, Humboldt, Marin, Merced, Napa, Placer, Sacramento, San Mateo, Solano, Sonoma, Stanislaus and Yolo.

“We are asking for the cooperation of anyone who purchased grapevines or citrus trees between April 21 and May 20 from Costco Wholesale warehouses located in any of these counties,” Carter said. “We understand that people may be reluctant to part with these plants, but it is critically important that the spread of this devastating pest is contained quickly.”

Carter noted that preventing the pest from becoming established will significantly reduce the need for future pesticide applications and costly eradication programs – another important reason for public cooperation.

The glassy-winged sharpshooter damages plants primarily by spreading Xylella fastidiosa, a deadly bacterium that causes Pierce’s disease in grapevines. In addition to grapevines, the pest attacks hundreds of plant species including almonds, citrus, stone fruit, alfalfa, and ornamental plants.

Public Guidance

Residents who purchased potentially affected plants are being asked to take the following steps immediately:

• For grapevines: Place two garbage bags securely over the plants and seal them tightly.
• For citrus trees: Contact your local County Department of Agriculture/Weights & Measures to schedule an inspection.
• Do not place plants in household trash or compost bins.
• Contact your local County Department of Agriculture/Weights & Measures for guidance on preventing further spread of the glassy-winged sharpshooter.

Costco Wholesale has been cooperative in assisting officials with tracing plant shipments and identifying affected retail locations. The chain has issued a notice to customers who purchased plants associated with this incident stating they are eligible to receive a full refund.

Because the glassy-winged sharpshooter thrives in both agricultural and urban environments, local agricultural departments actively monitor its spread throughout California. When dangerous invasive pests or diseases are detected, County Agricultural Commissioners play a central role in every phase of response, including detection, containment, eradication, enforcement, and public outreach.

“Agricultural Commissioners are the experts when it comes to local agricultural conditions, crop locations, pest pathways, seasonal conditions, and high-risk sites,” Carter explained. “The role they play is critical to protecting our nation’s food supply, a significant portion of which is produced in California.”

Carter added that the scale and complexity of invasive pest threats facing California have increased dramatically over the past three decades due to expanding global trade and travel.

“California’s pest prevention system has been strained by budget cuts, staffing shortages, and outdated infrastructure and technology,” Carter said, referencing a recent report issued jointly by CACASA and the California Department of Food and Agriculture. “An emergency involving a pest capable of damaging multiple major crops only underscores the importance of strengthening these systems.”