In California, the problem was that rootstock believed to be resistant to phylloxera turned out to be ineffective against a new breed of the insect. In Oregon, the problem is that at least 70 percent of Oregon's 9,000 vineyard acres are planted on their own roots, which lack any kind of phylloxera resistance.
At Rex Hill Vineyards, for example, president and winemaker Lynn Penner-Ash has been tracking one vineyard for several years. In 1995, she counted 60 vines with phylloxera in 1995. In 1998, the pest had spread to 500 vines. "We're actively replanting on rootstock," said Penner-Ash.
Other vintners are taking a somewhat less aggressive approach. "Some of us have had [phylloxera] for years without any big problems," said Adam Campbell, winemaker for Elk Cove Vineyard in Gaston. "We're just doing about one-third of our new plantings on rootstock, so that when we are hit with phylloxera we can replant without it being devastating."
"That's not what I would do," warned Jim Fisher, research entomologist with the U.S. Department of Agriculture research lab in Corvallis, Ore. "I wouldn't plant a vine on its own roots here."
Phylloxera burrows into the soil and attacks a vine's roots, eventually killing the plant. Until the vine dies, its grapes can make sound wine that is perfectly safe to drink. While native American vine varieties have a natural resistance to the louse, the European varieties from which most wines are made do not.
Nonetheless, Oregon vintners are optimistic that the spread will be slow and containable for several reasons. Unlike Napa and Sonoma counties in California, where vineyards carpet the landscape, Oregon vineyards tend to be scattered. To spread, the insect must travel much farther. Also, Oregon also has a cooler climate, which apparently slows the reproductive pace of the insect.
So far, phylloxera has advanced more slowly in Oregon than it did in California. Up to 1998, Fisher said, "the average vineyard where it appeared was 10 to 15 years old, and some were as much as 18 years old. And my suspicion is that it came in with the vines. So it took a while."
Fisher explained that the louse's breeding rate has averaged only two to two-and-a-half generations a year in Oregon, compared to six to seven generations a year in California. He added, "You don't just dig into the ground and come up with a shovel full of phylloxera, like they did in California. I have to dig around for four or five hours to find it."
Some vintners are exploring new theories of composting in the vineyard that claim to stop phylloxera from breeding. "It sounds like a lot of biodynamic mumbo -jumbo, but it looks promising," said Laurent Montalieu, winemaker for WillaKenzie Estate, part of a group of small wineries looking into composting. "With the right mix in the compost, it seems to keep the insect from reproducing, and improve yields in underproducing vineyards. One of our growers is trying it this year."
Well aware of the problems that California experienced, Oregon vintners know they are in for a long battle. "Whether they want to admit it or not, everybody's got phylloxera here," sighed Craig Broadley, whose 15-acre vineyard in Monroe has phylloxera, even though it is miles from the nearest vineyard. "You see a lot more interplanting [replacing of vines one by one] than you used to. We're going to be dealing with this for years."
For more on the effects of phylloxera:
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