California agricultural officials are urging customers to isolate and report plants purchased from Costco after the discovery of the invasive glassy-winged sharpshooter (GWSS), a leafhopper that spreads Pierce's disease, a fatal infection in grapevines. The insect, native to the southeastern U.S. and northeastern Mexico, was found in desert willow plants sold at select Costco locations from June 24 to July 3, following an earlier detection in grapevines earlier this year.
Immediate Action & Core Facts
The California Department of Food and Agriculture (CDFA) has issued warnings to customers who bought desert willows from Costco, advising them to isolate the plants and contact local agricultural officials. The GWSS can transmit Xylella fastidiosa, the bacterium causing Pierce's disease, which blocks a plant's water-conducting system, leading to vine death. There is no treatment for infected grapevines, which must be removed to prevent further spread.
Deeper Dive & Context
Economic and Environmental Impact
California's $73-billion wine industry is particularly vulnerable, as the state produces over 90% of U.S. grapes. The GWSS also threatens citrus trees, landscape plants, and other crops. Early detection and rapid response are critical to limiting its spread, according to the CDFA.
Historical Context
The GWSS was first detected in California in 1999, likely introduced through nursery stock. The U.S. National Invasive Species Information Center and the USDA have emphasized the need for vigilance to protect agricultural sectors.
Public Response
Costco has not yet responded to requests for comment, and the CDFA has not provided additional details beyond its initial warnings. The USDA states that once symptoms appear, infected grapevines must be destroyed to prevent further contamination.