Attack Of The Wine Bugs

Vineyard manager Dave Pirio scans the perimeter of the 53-acre PlumpJack Winery in Napa Valley, Calif., looking for the enemy. Kneeling low to the ground, he flips over big, shiny grape leaves one by one, hunting for the dreaded glassy-winged sharpshooter. The half-inch-long, muddy-brown insect has single-handedly decimated 30 percent of the wine crop in southern California's Temecula Valley over the last four years, and now threatens to wreak similar havoc here in the nation's premier wine region. "It would be absolutely devastating to our industry if that bug got in here," says Pirio's boss, PlumpJack general manager John Conover. "Our economy would tank."

To grape vines, the glassy-winged sharpshooter is as deadly as a malarial mosquito. The bug spreads a fatal bacterium called Pierce's disease that chokes off a vine's circulation, making it impossible for water to circulate and nourish the plant. The bacterium itself is present in small amounts in almost every vineyard, but infected plants can usually be identified and plucked out since Pierce's disease grows slowly. Throw the sharpshooter into the mix, however, and the disease spreads like wildfire as the insect inserts its stylus into the woody grapevine and then jumps from plant to plant.

The sharpshooter first hitchhiked a ride west about a decade ago on ornamental nursery plants from its native Florida. In Florida it had plenty of natural predators, which kept the population in check. But in California it has no natural enemy--except man. So when the glassy-winged sharpshooter started populating southern California's wine-growing region four years ago, unsuspecting farmers there lost about $14 million of vineyards before they knew what hit them. One Temecula winery, Calloway Coastal, has been forced to buy 60 percent of its grapes from independent growers outside the area.

But the real feast awaits. The sharpshooter is moving northward, up the California coastline and inland to ever richer vineyards. Already the bug is threatening about 60 wineries in Santa Barbara County. At Lafond Winery, vintner Bruce McGuire has set hundreds of sticky pest strips to catch the bugs, which are lurking just a few miles to the south. "We're all trapping up here," McGuire says. The Santa Ynez Valley is the geographic door to an enormous agricultural region spreading north through central California that produces $2.8 billion annually in wine, raisin and table grapes.

Luckily, vintners like McGuire don't have to take aim alone against the glassy-winged sharpshooter. Each day hundreds of inspectors with the California Department of Food and Agriculture examine tens of thousands of nursery plants destined for retail stores around the state in an effort to ensure that sharpshooters aren't hitching a ride. Government scientists are also breeding tiny wasps imported from Mexico that have a taste for the sharpshooter's larva; every other week about 10,000 of the little stingers are sent into battle in California's fields. The state and federal governments have spent $40 million on the eradication efforts over the last 18 months. This week state lawmakers will consider two bills to boost funding by at least an additional $5 million annually; in this case, the winemaking industry would be taxed to pay the tab. Entomologist David Morgan, in charge of the wasp program, says the extra money can't come too soon: he worries about what will happen during the hot summer months ahead, when the sharpshooters hit peak maturity and develop an acute case of the munchies. "It looks like there will be quite a few this season," he says. "If that's true, we'll have to be even more alert."

With the most to lose, Napa's growers are on high alert. Were the glassy-winged sharpshooter to get a winghold in any of the Valley's 30,000 planted acres, it could mean the end to some of the world's best wines and a blow to the region's $2.2 billion industry. That's especially true in the exclusive Oakville appellation of Napa, where so-called cult wineries like Harlan Estate, Screaming Eagle, Opus One and PlumpJack maintain some of the most coveted vineyards in the world. "We've got posters of that bug in our tasting room and in our offices. Our vineyard workers have little cards with pictures that show what the thing looks like," says PlumpJack's Conover. "We'll be ready, because it's tough to imagine that the agricultural inspectors can look at every leaf to catch every bug." Advice to the oenophile: stock up on your favorites now. They could become quite rare.