California winemakers are expressing grave concern after the invasive glassy-winged sharpshooter (GWSS) pest was discovered in plants sold at Costco stores across dozens of counties. This marks the second such incident in recent months and poses a significant threat to the state's vital wine industry.
The GWSS spreads Pierce's disease, an incurable and ultimately fatal condition for grapevines that causes them to dry out. The pest does not pose a risk to humans or animals.
In a recent incident, the Sacramento County Agricultural Commissioner's Office identified GWSS egg masses on desert willow plants sold at Costco locations in Sacramento and Marin counties. These plants originated from a nursery in Texas and were distributed to over 80 counties statewide.
Officials stated that while most of the infected plants were destroyed—209 out of 215 shipments were intercepted—the whereabouts of six plants remain unknown. "The counties are being very diligent in trapping and trying to alert our nurseries to give us calls," said Sacramento County Agricultural Commissioner Chris Flores. "We do not want this stuff getting out."
Marin County Agricultural Commissioner Joe Deviney reported that his office destroyed all 24 desert willow plants they received after discovering various life stages of the pest. These plants had been shipped between April 21 and May 21 to Costco locations serving Napa, Sonoma, Marin, Solano, Merced, Sacramento, Stanislaus, and Yolo counties.
This discovery follows a similar event in May when GWSS eggs were found on grapevines originating from Burchell Nursery in Fresno County. These vines were delivered to Costco stores in several Northern California counties.
"While many vines have been intercepted and destroyed, locating the thousands that may still be in customers’ hands remains our top priority," stated California Secretary of Agriculture Karen Ross. The prospect of eradicating the pest is described as "difficult and costly," with potential losses from Pierce's disease threatening to devastate local vineyard, winery, and tourism industries.
California Congressman Jimmy Panetta highlighted the pest's threat to the state's agricultural economy, estimating potential annual losses exceeding $100 million for wine and table grapes. Panetta and other state lawmakers are urging the federal government to release $32.2 million in emergency funding to combat the invasive species and safeguard agricultural producers.
Historically, Pierce's disease has caused substantial economic damage. A 2008 University of California study indicated that between 1994 and 2000, the disease resulted in nearly $30 million in losses and the destruction of over 1,000 acres of grapevines in Northern California. The GWSS was first detected in California in 1994. In 2019, an outbreak in Sacramento County was narrowly prevented through stringent quarantine measures.
Agricultural officials are advising anyone who purchased the affected plants or vines to contact their local agricultural commissioner's office immediately.