Calif. lawmakers ask for emergency funds after dangerous pest spotted at Costco

Just a month after glassy-winged sharpshooters were discovered on grapevines sold at Northern California Costco stores, the wholesale retail giant has made headlines again for selling plants that showed signs of carrying the invasive pest. 

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Last week, Costco stores in Sacramento and Marin counties received desert willow plants that had egg masses from glassy-winged sharpshooters, or GWSS, an invasive pest known to kill plants and spread disease. The Sacramento County Agricultural Commissioner’s Office told the Sacramento Bee that the plants were shipped from a nursery in Tyler, Texas. 

“The counties are being very diligent in trapping and trying to alert our nurseries to give us calls,” Chrisandra Flores, the Sacramento County agricultural commissioner, told the outlet. “… We do not want this stuff getting out.” 

GWSS, which were first discovered in California in 1989, pose a significant threat to plants when they feast on them and introduce diseases and bacteria. California’s wine industry is particularly at risk of GWSS because the pest can infect grapevines with Pierce’s disease, which causes the vines to dry up. Earlier this month, California lawmakers asked the federal government for $32 million in emergency funding to battle the pest, fearing that GWSS would create a “potentially catastrophic threat” and a financial loss of $104 million to the wine industry, according to Bay City News. 

In May, the California Department of Food and Agriculture urged Costco consumers to call their local county agricultural commissioner’s office when the invasive pest was found in grapevines sold at Northern California stores between April 21 and May 21. According to Bay City News, the grapevines, which originated from a Fresno County nursery, were sold to Costco and shipped around Napa, Sonoma, Marin, Solano and Yolo counties. 

It’s unclear when Costco discovered it had plant shipments with GWSS eggs. SFGATE reached out to Costco and the Sacramento County Agricultural Commissioner’s Office for comment but did not hear back by publication. Flores told the Bee that the plant shipments to Costco did not have inspection notices when they arrived at Costco stores, and that her team later destroyed 209 of 215 infested plants at multiple Costco stores, but they are still searching for six missing plants. Flores urged anyone who purchased a desert willow from Costco to call her office. The plants were expected to be sold at more than 85 Costco stores across the state, according to the Sacramento Bee. 

Joe Deviney, agricultural commissioner for Marin County, told the Sacramento Bee that Costco asked his office to inspect the plants that likewise did not have proper inspection paperwork. His team found six egg masses, including two egg masses that showed the pest had emerged. According to the Bee, Deviney’s office destroyed 24 desert willows in shipment before any were sold and also helped alert other California counties. 

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Mark Hoddle, director of UC Riverside’s Center for Invasive Species Research, told SFGATE that Northern California already has its own native sharpshooter bug, but the non-native GWSS is harder to kill because it’s larger, can penetrate deeper into plants and spread Pierce’s disease further.

“The issue is that there are now more,” Hoddle said. “You’re going from small native sharpshooters to these non-native sharpshooters that are great at spreading this disease.” 

Hoddle said that GWSS are easy to identify, but finding the egg masses is a “daunting problem.” Following plant inspections, egg masses could be overlooked if they’re located on a single leaf within the plant. He added that it’s “remarkable” Costco discovered GWSS given the hundreds of plants moved into California from out of state every year.