Vineyard Pest Makes Fourth Appearance in Napa This Year

Glassy-winged sharpshooter eggs were found on plants shipped to a winery

Lynn Alley
Posted: April 26, 2005

Once again, the dreaded glassy-winged sharpshooter has made another visit--albeit a brief one--to Napa Valley. Averting a potential vineyard disaster, Napa County agricultural inspectors found two viable egg clusters last Friday on a shipment of crape myrtles that had been delivered directly to a winery in Deer Park.

"They hadn't yet finished unloading the truck when we found the egg masses," said Napa County agricultural commissioner Dave Whitmer. "They loaded up the plants they had already unloaded, sealed the truck and the whole thing got shipped back to the nursery of origin right then and there."

The glassy-winged sharpshooter, an insect that feeds on a variety of plants, carries Pierce's disease, which is deadly to grapevines. The pest entered California in the early 1990s and has mostly been confined to Southern California, where it nearly wiped out the Temecula wine industry in 1999. Since then, state and county agriculture officials have made concerted efforts to restrict the insect's spread northward.

This is the fourth time this year that viable sharpshooter egg masses have been found in the county on shipments from Southern California. There were no findings at all in 2003. Neighboring Sonoma County has also made four egg finds since February.

Whitmer said he is concerned that the pest has appeared so frequently this year and that apparently not all wineries in the area are taking the threat seriously.

"It quickens our pulse every time this happens," Whitmer said. "We really rely on everyone in the community understanding the significant risk, not only to themselves, but to everyone else in the wine industry. We would hope in particular that wineries and grapegrowers would understand the situation and not bring in plant materials from outside the county."