While Napa Valley officials investigate a possible glassy-winged sharpshooter infestation, neighboring Sonoma County is also facing a possible invasion of the vine-killing pest.
So far, there have been two cases of sharpshooter egg-mass findings this year--one on Feb. 17 and another on March 8--at two different nurseries in the city of Petaluma, in Sonoma County. Both shipments, like those found in Napa County, originated at nurseries in Southern California.
Both shipments were discovered by county agricultural inspectors doing routine inspections of shipments from Southern California. According to Sonoma County assistant agricultural commissioner Mike Smith, both shipments were immediately reloaded and sent back to southern California on the trucks that brought them. "We went for two years without finding anything, knock on wood," Smith said. "It may just be the warm winter in Southern California."
Unlike Napa County, Sonoma County does not inspect nursery shipments coming from counties considered to be uninfested, such as the recent shipment received in Napa from San Joaquin County.
San Joaquin County agriculture officials are currently inspecting the county looking for possible sharpshooter infestations or sources of last week's nursery shipment to Napa. While it was first believed that the eggs where on nursery stock when it arrived from southern California, agricultural officials said that that shipment arrived in Lodi over a month ago and that while sharpshooter eggs generally hatch within three weeks of being laid.
"There is a possibility that the [sharpshooter] eggs came from Southern California. However, they were in the Lodi nursery for five weeks before being shipped to Napa," said Vicki Helmar, assistant agriculture commissioner in San Joaquin County, implying that there is a possibility that the eggs may have been laid by a female sharpshooter already present in Lodi itself.
Helmar said the hunt for more sharpshooter evidence in San Joaquin County will continue. "We've done a thorough investigation of the lot and other lots in that nursery and we've put out hundreds of traps around the area. Since last Friday, we've found nothing."