Agricultural inspectors have trapped three more European grapevine moths in Sonoma County, resulting in quarantines on 9,000 acres of vineyards near Kenwood and Sonoma.
The quarantines are the first caused by insects found here rather than in moth-infested Napa County.
The new moths include one found near Kenwood, where another such pest was discovered three weeks ago, and two on agricultural lands east of Sonoma.
"It's serious, because where you have two, you have more," said county Agricultural Commissioner Cathy Neville.
As called for by state rules, all lands within three miles of the moths, or about 9,000 acres of vineyards near Kenwood and Sonoma, will be quarantined.
While some smaller areas of the county face quarantines due to moths found in Napa Valley vineyards, these are the first from moths found in Sonoma County. The exact boundary lines have yet to be established.
The affected growers can still ship their grapes to market, but they must agree to inspections or to rules that ensure they don't help spread the moth. Those rules have yet to be formalized.
Nick Frey, president of Sonoma County Wine Grape Commission, said the new quarantines and ongoing quarantines for the light brown apple moth are "bad things" confronting his industry.
"It's going to affect a lot of growers in the county," he said.
Grapevine moths, native to Mediterranean Europe, were first confirmed in the U.S. in September, when they were spotted in Napa Valley. They destroyed the crop in one Oakville vineyard and damaged other vineyards, state officials said.
They attack the berries and can infect them with botrytis, or bunch rot.
Neville reported to county growers last week that 6,000 moths had been trapped in Napa County. On Tuesday, Chief Deputy Agricultural Commissioner Stefan Parnay revised that count to more than 10,000 moths.
Napa growers are gearing up to fight back with pesticides, including those approved for organic operations. They're working with UC Cooperative Extension specialists to identify the best time to spray their vineyards.
Sonoma growers are likely to follow suit, Frey said.
Unlike the apple moth, native to Australia, grapevine moths feed primarily on grapes and appear to confine themselves to vineyards and nearby farmlands.
"We don't expect it to be a city issue like the (apple moth)," Frey said.
The quarantine boundaries for Napa are likely to expand again. Last week, a state official estimated that about 300 square miles are affected by moths in Napa's vineyards, including an area east of Glen Ellen and about 1,000 acres in Sonoma County's Knights Valley near Calistoga.