Invasive Pest Found on Grapevines Sold at Richmond Costco and Other Bay Area Stores

The Contra Costa County Department of Agriculture is warning consumers about an invasive insect, the glassy-winged sharpshooter, discovered on grapevines sold at five Costco stores across the county, including the Richmond location. The insect, a leafhopper native to the southeastern United States and Mexico, was first detected in California in the 1990s and has since established populations in central and southern parts of the state.

It feeds on over 300 plant species, including grapevines, citrus, almonds, and ornamental plants. In grapevines, it transmits the bacterium Xylella fastidiosa, which causes Pierce's disease, a condition that weakens and can kill vines, threatening Contra Costa County's wine industry and agriculture.

The insect poses no danger to humans or pets.

"The glassy-winged sharpshooter poses an immediate and serious threat to grapevines and agricultural landscapes throughout Contra Costa County," said Matt Slattengren, the county's agricultural commissioner. The infestation is part of a broader statewide incident involving shipments from Burchell Nursery, Inc.

in Oakdale, distributed to multiple counties. According to the Sacramento Bee, the University of California reported that Pierce's disease destroyed more than 1,000 acres of grapevines in Northern California from 1994 to 2008, causing $30 million in damage.

The glassy-winged sharpshooter is described as a "voracious eater" that consumes massive quantities of plant sap, draining nutrients and weakening plants. It also excretes copious amounts of watery, sugary liquid that leaves a sticky white residue, damaging fruit and blemishing cars or patio furniture.

An estimated 200 plants were sold in Contra Costa County before the insect was detected, with distribution in Danville, Concord, Brentwood, Antioch, and Richmond. Unsold inventory was destroyed after most plants were confirmed to have multiple life stages of the insect.

Officials urge anyone who bought a grapevine at an affected Costco after April 21 to contact the county immediately and not move or discard the plant. Costco is also contacting customers.

To prevent spread, keep the plant in its original pot away from other plants, place it in two sealed trash bags, and do not return, transport, or dispose of it in trash or compost bins. Call the Contra Costa County Department of Agriculture at 925-608-6600 for pickup and guidance.

In Napa County, 220 grapevines from the same nursery were sold, with only 63 destroyed and 157 unaccounted for. Marin County officials have also surveyed plants from earlier Novato Costco shipments and increased trapping efforts.