SANTA ROSA, Calif. -- Vintners in Sonoma and Napa counties are on alert for infestations of a Mediterranean insect that attacks roots, leaves and grapes.
Winemakers worry they'll have to spray harsh pesticides over delicate crops to eradicate the vine mealybug -- the latest nonnative insect to invade America's premier wine growing region.
Sonoma County already spends more than $200,000 per year to keep out the glassy-winged sharpshooter, an aggressive, disease-spreading insect that has ruined vineyards in Southern California. Sonoma and Napa counties are also fighting the olive fruit fly, Japanese beetle, Oriental fruit fly, gypsy moth, and mosquitoes that could carry the West Nile virus.
"It's a constant barrage," Sonoma County Agricultural Commissioner John Westoby said. "On any given day an exotic pest could be introduced into Sonoma County from anywhere in the world. Modern transportation and widespread travel are speeding things up."
Agricultural biologists first identified the mealybug in August at a Santa Rosa vineyard. Since then, mealybugs have infected a second Santa Rosa vineyard and seven in Napa County.
Biologists traced the Northern California mealybug outbreaks to a grapevine nursery stock in Southern California. The mealybug is a native of the Mediterranean coast, common in Europe, North Africa and the Middle East.
Individual mealybugs aren't as destructive as other pests that have invaded the region, including the Mediterranean fruit fly and phylloxera, a root louse. Vintners vanquished those pests more than a decade ago, but only after aerial spraying of malathion, which sparked a showdown between farmers and environmentalists.
Vintners -- particularly those with organic farms -- hope to stem mealybug infestations without resorting to chemicals. But because the mealybug comes from the Mediterranean and has few natural predators in California, small populations could mushroom.
"For several years now, the trend has been to manage pests with no pesticides or reduced levels of pesticides," said Nick Frey, executive director of the Sonoma County Grape Growers. "The vine mealybug could have an impact on those efforts."