Sonoma County Chief Deputy Agricultural Commissioner Stefan Parnay said one of the moths was found Aug. 10 in a trap on Ramal Road near the counties' border. The find was confirmed Aug. 13.
Assistant Napa County Agricultural Commissioner Greg Clark said the moth in Napa County was found July 23 off Duhig Road in the Carneros wine grape growing region.
The two most recent finds are about 1.3 miles apart and will be included in the same quarantine zone, Clark said. The quarantine will restrict the movement of fruits, vegetables and plants outside the zone. Parnay and Clark said farmers and grape growers will be contacted about the restrictions once the quarantine boundary is set by the state, possibly next week.
A 15-square-mile quarantine zone already exists in Sonoma County outside the city of Sonoma after two /*light brown apple moths*/ were found in February and April. That quarantine zone is seven or eight miles from the zone likely to be established near the Sonoma-Napa counties' border, Parnay said.
Some grape growers will be able to crash their grapes on their vineyard sites, Parnay said.
Clark said he doesn't expect the quarantine restrictions will be "onerous" to grape growers who want to get their crop transported and processed.
"There's nothing to indicate there is a possibility of moths breeding out there. They could possibly have blown in or been transported there another way," Clark said. "Grapes don't pose a significant risk of spreading the light brown apple moth."
Any moths would be removed by the harvesting process itself and it's unlikely they would be transported off the vineyard site during the harvest, he said.
State agricultural officials say 2,000 plants are known to be susceptible to attack by the apple moth they say threatens California's cypress, redwood and oak trees and food supply.
The moth, native to Australia, destroys, stunts or deforms young seedlings, spoils the appearance of ornamental plants and injures citrus, grapes and deciduous fruit tree crops, according to agricultural officials.
The California Department of Food and Agriculture canceled plans in June to aerially spray a mating-disrupting pheromone in the Bay Area this summer to eradicate the moths.
Officials said the state instead will begin to introduce large quantities of sterilized, infertile moths in 2009 so the population cannot reproduce.
Pheromone-laced twist ties have also been applied to trees and plants in areas where moths have been found. That too has met local opposition.
