Agricultural operations across Northern California had to mobilize over the past week after discovering a Fresno nursery had shipped hundreds, if not thousands of staked grapevines to Costco warehouses without noting the plants originated from an area that has been infested by the glassy-winged sharpshooter, an insect with the potential to devastate vineyards.
On Tuesday, May 26, multiple counties — including Sonoma and Napa — acknowledged that agricultural inspectors had found sharpshooters “in multiple life stages” at Costco outlets in their jurisdictions.
Those life stages include egg masses, juvenile nymphs and fully developed adult insects, according to Sonoma County Deputy Agricultural Commissioner Pierpaolo Aymar, who is in charge of quarantine programs at the agency.
The glassy-winged sharpshooter is known to spread Pierce’s disease, which can be a death sentence for grapevines. Because of that danger, any nursery shipping vines from an area of infestation is supposed to put a hold requirement on those deliveries, so the receiving party can notify local agricultural authorities and schedule inspections.
That didn’t happen in this case, Aymar told The Press Democrat.
He said that Burchell Nursery in Fresno shipped a total of 634 plants to the Costco warehouses in Santa Rosa and Rohnert Park. Inspectors were able to destroy 241 of those plants, but 393 remained unaccounted for at midday Tuesday.
The Napa Costco received 220 grapevines from Burchell, according to a Napa County press release; 63 of them were destroyed, leaving 157 unaccounted for. Inspectors found one egg mass at Napa Costco.
Napa Valley Grapegrowers executive director Caleb Mosley called the shipment of infested vines “a major breach,” and an immediate challenge for an industry already facing economic headwinds.
“Overall, Napa County growers have done a fantastic job. And Pierce’s disease seems to be less of an imminent threat these days,” Mosley said. “But that could all change in an instant if this sharpshooter gains a foothold in the county. To say we’re concerned is an understatement.”
The glassy-winged sharpshooter “is a devastating pest for our local vineyards, and it is critical for us to track down any potentially affected plants purchased at Costco or brought into Napa County,” Napa County Agricultural Commissioner Tracy Cleveland said in the press release.
Marin, Mendocino and Solano County Costco outlets also received suspect plants from the San Joaquin Valley nursery.
“All affected counties are responding with enforcement actions and seizing and destroying the infested plants,” according to a Sonoma County press release.
Burchell Nursery, which is based in Oakdale, did not respond to an email. The Press Democrat was unable to reach Costco corporate representatives.
The big-box wholesaler is working closely with county officials across the affected area to identify as many of the remaining plants as possible. One Bay Area Reddit user posted a notice they had received from Costco on Friday, alerting the customer that records indicated they’d purchased Item #197266 – Staked Grape Vine – between April 21 and May 21.
Those are roughly the dates mentioned in the county releases as well.
“Costco has been a tremendous help with us,” Aymar said. “They’re done everything we’ve asked them to do. They sent notices to their members to reach out to our department if they bought one of these plants. That’s already happened – we’ve received a bunch of phone calls (Tuesday).
“This is not a Costco problem, it’s a nursery problem,” Aymar said.
On May 19, according to officials in the Sonoma County Agricultural Commissioner’s Office, the Costco store in Santa Rosa notified the agency that it had received a shipment of grapevines originating from Burchell Nursery.
After visiting the Costco and finding evidence of sharpshooter infestation, the Sonoma County office contacted Burchell to determine additional drop-off points. Staff was informed that the same truck had delivered vines to the Costco warehouses in Rohnert Park and Novato; inspectors found additional evidence of glassy-winged sharpshooter infestation at the Rohnert Park outlet.
County staff informed the California Department of Food and Agriculture and notified other counties of the at-risk deliveries.
Officials are requesting that anyone who purchased citrus plants from the impacted Costcos also contact local agricultural offices. The glassy-winged sharpshooter is attracted to citrus, too, though it generally doesn’t harm those species.
As pests go, this one is likely Public Enemy No. 1 for grapegrowers.
Several species of sharpshooter can spread the bacterium that causes Pierce’s disease. “The difference with the glassy-winged sharpshooter is that it’s considerably larger, and able to travel further distances,” said Cindy Kron, an advisor with UC Cooperative Extension’s integrated pest management team for the North Coast.
For those reasons, the ag department has 400 sharpshooter traps placed around Sonoma County. Once in a while, Aymar said, staff will find “a one-off hitchhiker.”
Exposure on this scale, he said, is a different matter altogether.
Sonoma and Napa counties posted similar advice to residents who may have purchased a grapevine, citrus tree or other fruit tree from a local Costco in April or May:
• Keep the plant isolated in its original pot or container.
• Do not plant the grapevine or tree if you have not already done so.
• If possible, place the plant in two secured trash bags, one inside the other, and seal them closed.
• Do not attempt to return, transport, or relocate the plant.
• Do not place the plant in the trash or a compost bin.
• In Napa County, immediately contact the Agricultural Commissioner’s Office at 707-253-4357 or agcommissioner@countyofnapa.org; in Sonoma County, contact the Department of Agriculture/Weights and Measures at 707-565-2371 or sonomaag@sonomacounty.gov.
The pest can also damage almond and citrus plants, as well as various ornamentals, though it isn’t considered as lethal to those species.
You can reach Staff Writer Phil Barber at 707-521-5263 or phil.barber@pressdemocrat.com. On X (Twitter) @Skinny_Post.
You can reach Staff Writer Edward Booth at 707-521-5281 or edward.booth@pressdemocrat.com.
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