Invasive Insect Discovered in California Grapevines
An emergency alert issued on Tuesday by the Napa County Agriculture Commission raised alarms throughout California after an invasive insect linked to a serious vineyard disease was detected in grapevines sold at Costco Wholesale, affecting several counties.
It was confirmed that the grapevines shipped from Burchell Nursery in Fresno County made their way to Costco locations serving Napa, Sonoma, Marin, Solano, and Yolo counties.
In total, 220 vines were shipped between April 21 and May 26, including some that ended up at Costco in Napa.
The main concern here is the glassy-winged sharpshooter (GWSS), an insect resembling a cricket that poses a significant risk to California’s agricultural landscape.
While this pest doesn’t harm humans or pets, it can severely damage plants by spreading Pierce’s disease, a bacterial infection that disrupts water flow, eventually leading to the drying out of the vines.
Unfortunately, there isn’t a cure for this disease.
Tracy Cleveland, Napa County Agriculture Commissioner, noted that inspectors have already destroyed some of the affected shipments upon finding GWSS.
Out of the 220 vines that went to Napa Costco, 63 were destroyed, and one egg mass of the GWSS was identified. The remaining 157 vines may be in the hands of local residents who bought them at the store.
Costco is reaching out to impacted members to address the issue and is collaborating with county agriculture officials.
Cleveland emphasized the need to monitor potentially affected plants brought into Napa County. She expressed confidence in the community’s ability to work together to reduce risks to local agriculture. Keeping vigilant and reporting any concerns quickly is essential.
Typically, vines bloom and produce small fruit in May, but the infection can hinder their growth. Surprisingly, signs like “burnt” leaves may not show up until late summer, complicating early detection.
Officials are concerned that if the GWSS becomes established, it could lead to long-term consequences. They pointed out that eliminating the pest is challenging and costly, and the potential losses from Pierce’s disease could be devastating for vineyards, wineries, and even the tourism industry.
Historical data suggests the gravity of this threat. A study from 2008 by the University of California found that between 1994 and 2000, Pierce’s disease resulted in nearly $30 million in losses and decimated over 1,000 acres of vines in Northern California.
In 2019, a previous outbreak was contained in Sacramento County thanks to strict quarantine measures.
The glassy-winged sharpshooter was first identified in California back in 1994.
