What are glassy-winged sharpshooters? Invasive insect sparks Costco recall

A tiny invasive insect is prompting agricultural officials in California to track down and remove thousands of plants sold through Costco, over fears it could threaten vineyards, farms and the state’s multibillion-dollar wine industry.

The pest, known as the glassy-winged sharpshooter (GWSS), is a large leafhopper—which are plant-eating insects, known for their ability to jump long distances—which is native to the southeastern United States and northeastern Mexico and became established in California during the 1990s. The U.S. National Invasive Species Information Center believes it was likely introduced through the movement of nursery stock.

While the insect itself doesn’t harm humans or animals, agricultural experts consider it to be dangerous because it can spread Xylella fastidiosa, the bacterium responsible for Pierce’s disease, a potentially fatal infection in grapevines. The sharpshooter feeds on plant fluids and can transmit the bacterium as it moves between plants.

“There is no treatment for Pierce’s disease,” according to the U.S. Department of Agriculture (USDA). Once an infected grapevine develops symptoms, it typically must be removed and destroyed to prevent further spread.

Newsweek has reached out to the California Department of Food and Agriculture via email for comment but hasn’t received a response by the time of publication.

Why Is The Insect Dangerous?

The immediate concern is the potential spread of Pierce’s disease into vineyards and residential gardens. The disease blocks the plant’s water-conducting system, causing leaves to discolor, grapes to shrivel and vines to eventually die, says the USDA.

The long-term implications could be far more significant.

California produces over 90 percent of US grapes, making its vineyards especially vulnerable to pests that can spread Pierce’s disease. According to recent California Department of Food and Agriculture (CDFA) reports, the direct value of the state’s grape crop, including wine and table grapes, is estimated at roughly $5 billion to $5.6 billion.

Broader estimates, including the wider economic impact of California’s grape and wine industries, have placed the figure much higher, with Farm Together citing an economic contribution of around $44 billion.

The pest has already demonstrated its destructive potential. A major Pierce’s disease outbreak in Temecula Valley in 1999 destroyed more than 300 acres of vineyards and helped trigger a statewide response program, according to the Los Angeles Times.

Beyond grapes, the insect can also affect citrus trees, almonds, oleander and various landscape plants by spreading related plant diseases.

Which Costco Plants Have Been Recalled?

The current alerts involve two categories of plants sold at Costco stores in California.

The CDFA says glassy-winged sharpshooters were found on the following plants, sold at selected Costco stores across the state:

• Grapevines sold between April 21 and May 21, 2026
• Desert willow plants sold between June 24 and July 3, 2026

Santa Clara County officials say more than 1,300 grapevine plants were sold to customers there alone, with approximately 1,180 still unaccounted for as of mid-July.

This has prompted county agriculture workers to go door-to-door delivering collection kits and arranging pickups.

Costco customers who purchased affected plants have been urged to report them immediately so agricultural inspectors can examine and, if necessary, safely remove them.

Who Is Affected?

Currently, the Costco plant recall effort is focused on California and is not nationwide.

The CDFA has identified that the affected plants were sold in numerous counties, including:

• Santa Clara
• Alameda
• Contra Costa
• Marin
• Napa
• Placer
• Sacramento
• Solano
• Sonoma
• San Mateo
• Stanislaus
• Yolo
• Yuba

What Should Consumers Do?

The CDFA is advising anyone who has purchased the affected grapevines or desert willows to:

• Keep the plant isolated from other vegetation.
• Leave it in its existing container if possible.
• Double-bag the plant if instructed.
• Avoid transporting, composting, relocating, or disposing of it independently.
• Contact their local county agricultural commissioner’s office for inspection and guidance.

Agricultural authorities say rapid reporting is critical to preventing the insect from becoming more widespread.

Early detection and removal remain the primary ways to stop the pest from establishing new populations and threatening California’s vineyards and plant industries.

Contact Newsweek editors on this story: John Fitzpatrick and Cristina Diciu.