continued "These [sharpshooters] end up consuming more food per body weight than any other terrestrial animal on earth. Up to 1000 times their weight a day in food," says Purcell. "They insert a sort of hypodermic needle into the xylem. Like into a vein." Because the xylem-sap they feed on is so nutrient-poor, they have to drink enormous amounts of it to survive. Once the Xylella bacterium enters the vine's "bloodstream" and starts to block the movement of water from the roots up to the leaves, Purcell says, the vine's fate is sealed. "They multiply like crazy. One billion bacteria per gram is not uncommon."
Yet it may be two years, he says, before a grower even knows that a vine is stricken. The prospects for fall 1999 don't look good, he believes, because there's bound to be an exploding population of sharpshooters this El Niño spring.
Vince Lazaneo agrees. "Insect populations go through cycles in relation to the temperature, and to the luxuriance of the vegetation that's out there," he says. "So during wet seasons, there's more likely to be more vegetation, and more insects reproducing. And with our natural dry cycle during the summer and fall, as that native vegetation dries down, these insects like to migrate to nearby irrigated vegetation, and thus can transmit whatever [bacterium] they might contain. It's [tough] to control, because you only have to have one insect feed one time on a plant to transmit it."
Pierce's Disease used to be thought of as a "Southern California" disease. No more. According to Purcell, it's now approaching epidemic proportions in the great northern wine-growing areas of Napa and Sonoma. "Napa and Sonoma Valleys lost $33 million last year to this disease. That's just the loss to the grower of the value of the land for three years -- the time it would take you to replant."
The disease has already eliminated a few small vineyards in the Santa Cruz mountains, and it's threatening to do that to some small vineyards in the Napa Valley too. According to Ben Drake, president of the Temecula Valley Wine Grape Growers Association, the disease has been in Temecula for "a couple of years" already. He told a local paper the owner of one small vineyard plans to destroy the current crop and won't bother replanting.
Leon Santoro does not want his vineyard to become a statistic. Orfila already has had an uphill battle fighting the inevitable image problems of being a San Diego, and not a Napa or Sonoma, winery. "It's such an irony," says Santoro, who used to co-own a Napa Valley winery, Quail Ridge, himself. "San Diego is the original California wine country. This is where Father Serra planted California's first grapes. This is the ideal Mediterranean climate."
Santoro has prizes to back his claim: since 1994, his Orfila wines have garnered a couple of dozen gold medals and three double golds in international competitions. His Syrah and Sangiovese wines have been recommended in the Wine Spectator.
"We have won 202 medals in four years," he says, standing among his threatened Chardonnay vines, which produced the grapes that won seven of those medals. "We're fighting two things: Pierce's Disease and people's perception that real wines come from Northern California. Winemaking demands a combination of climate, soil, and luck. We have the climate and soil. We just need a bit of luck."
The latest piece of bad luck is news that the blue-green sharpshooter's bigger cousin, the glassy-winged sharpshooter, is now spreading through the area. All Santoro can do is what Professor Purcell tells him to. Spray if necessary, get rid of nearby ornamental plants that might be good reproduction hosts for the sharpshooters, and change to reds, such as Syrah and Sangiovese, which appear to be tougher.
He's also following a few of his own ideas.
"I have about 15 owls who hunt voles at night, and hawks who hunt by day. I try to be as organic as possible, to encourage birds and other creatures that like to feed on sharpshooters. These are things my grandmother did in her vineyard in Italy when I was a boy. I never thought I'd be looking to her for help."
Professor Purcell says Santoro can't do much more until the day vines can be genetically altered to become resistant. And that's years -- maybe decades -- away.
"If he holds at 5 percent average losses, that's not too bad," says Purcell. "He can keep going with those kinds of annual losses, although he's taking a beating."
Leon Santoro lifts up a slightly scorched leaf of one of the sick plants. "A vine is like a person," he says. "Disease doesn't have to be fatal."