Authorities are warning about pests that are invading California's grapevines
A pest considered a major threat to California's vineyards and its $73 billion wine industry was found in grapes sold at Northern and Central California Costco stores between April 21 and May 21, according to authorities.
The glassy-winged sharpshooter, which was first identified and discovered May 19 on vines sold at a Fresno grocery store, is a small invasive insect that can spread a type of bacteria, Xylella fastidiosa, that kills grapevines by “clotting the xylem vessels.” The fatal disease is called Pierce's disease. Many other types of bacteria exist and can infect other host plants, including citrus, stone fruit, almonds, oleander and other shade trees, according to California Pierce Disease Control Program.
If the pest is left unchecked, the disease could cost California's wine industry $166 million a year, California Department of Food and Agriculture officials said in an email.
This insect is characterized by its flat triangular head, large eyes and clear wings. The head is brown to black and has several ivory to yellow spots, which help distinguish it from its native counterpart, the smoke tree shooter. This insect is often found on plant stems and grows to about half an inch when fully grown, according to University of California.
“While many vines are seized and destroyed, getting the thousands that may be in the hands of customers remains our top priority,” California Secretary of Agriculture Karen Ross said in a press release. “Anyone who bought these vines should contact the local agricultural commissioner immediately.”
California's wine grape industry supports more than 422,000 jobs statewide, according to the CDFA.
The glassy-winged sharpshooter was first reported in California in the early 1990s and is native to the southeastern US and northeastern Mexico. This insect was first identified as a threat in August 1999, when more than 300 acres of grape vines in Temecula were attacked by Glass-winged Sharpshooter and Pierce's disease and subsequently destroyed. CDFA reported.
Overall, the disease costs farmers and government agencies about $110 million a year in lost costs and compliance costs, according to a March 2025 report titled. Costs of Pierce's Disease in the California grape and wine industry.
Up to 13,000 potentially infected vines have been sold across 24 Northern and Central California counties, the CDFA said.
“In addition to destroying stock in Costco stores, CDFA is working with agricultural commissioners and doing community outreach to get vines sold to consumers in all 24 counties, as well as neighboring counties at risk,” CDFA officials said in a press release.
“Officials respond to public reports, inspect and contact the public, and close off stores and areas where purchased vines were taken. They also ensure that potentially infested plants are stored and disposed of safely,” said a press release.
Costco also worked with the CDFA to notify customers, provide refunds to those who purchased the vines and helped connect them with local agriculture officials in the affected counties “for inspection and disposal,” the CDFA said in a pest statement.
Authorities are asking residents who bought these vines in affected counties to follow strict guidelines, including separating the plant and wrapping it in two garbage bags and contacting the county's agriculture commissioner, authorities said.
