An unwelcome intruder has arrived in the Walla Walla wine region.
Phylloxera, the notorious plant louse that lives on and attacks the roots of grapevines, famously brought on the near decimation of French vines about 150 years ago and in more recent times cost California growers a reported $1 billion to rip out and replant almost three-quarters of the vineyards in Napa and Sonoma in the 1990s. Now it has been discovered here.
Grape, wine and other industry experts aren’t exactly hitting a proverbial panic button. Phylloxera is not a complete stranger to Washington state.
But its previous detections have been contained through the years, leading many to believe the local vines would remain free from its damage. Given though that the majority of the world’s wine regions have been touched by it, the odds were not in Walla Walla’s favor, said Vicky Scharlau, executive director of the Washington Winegrowers Association.
“It’s the nature of agriculture,” she said. “It’s always some disease. It’s always something. Mother Nature has her way with us.”
Years of history with phylloxera in other wine regions and their experiences overcoming it bring comfort that neither the vines nor the wine itself — the latter of which is not at all affected by the microscopic insects — are in immediate danger.
Phylloxera doesn’t kill the vines. Often described similarly to aphids, the insects puncture the root surfaces and feed off the sap. They don’t suck the vines dry themselves. Instead, the open wounds they leave allow other pathogens in while also making it difficult for the vines to absorb water and necessary nutrients. This leads to the slow death of the plants as grape production slows to a halt.
Grape quality is unaffected, as is the wine produced, experts say. So this isn’t an issue that directly affects consumers.
What it could mean, however, is a long-term shift in rootstock for a wine region that has been reputed, by some, for being “own rooted,” or growing grapes on their original root systems.
“I think there are many people who use that as a point of differentiation from other wine regions,” Scharlau said. “Will that change immediately? No. No, no, no. Will that change over time? Likely. But we have a lot of time.”
With the breadth and width of the phylloxera presence yet unknown but believed to be limited, one of the initial steps for the industry is working to keep it from spreading.
Discussed in local wine industry circles since late last month, the industry has been working together to share information and practices, said Liz Knapke, marketing manager for the Walla Walla Valley Wine Alliance.
“The industry here is being really proactive and sharing information to face the challenge” in unity, she said. “I think Walla Walla has proven it’s the community that can do that over and over and over again.”
The Washington Winegrowers Association and Washington State Wine, which represents every licensed winery and wine grape grower in the state, have been distributing recommendations for best sanitation practices.
Grape phylloxera can be spread from site to site through soil. As harvest begins, that means the bugs can travel on everything from tractor wheels to shoe treads.
Consequently, wine and viticulture experts urge sanitation procedures to help reduce insect movement.
Among recommendations: controlling access to the vineyards, clearly labeling bins, loading and unloading trucks on a paved or gravel roadway outside of the vineyards, and restricting vehicles to paved areas and delivery trucks to sanitation pads.
Phylloxera has long been present in Washington vineyards, experts say. Steve Warner, president and CEO of Washington State Wine, said phylloxera was first detected around 1910. It was also detected about 60 years ago in concord vineyards. That’s been relatively contained.
“We’ve been somewhat lucky in a sense that we’ve known it’s been around,” he said.
“We need to continue surveillance. We need to do what we should be doing, which is best management practices in the vineyard. That applies to any types of pests.”
Why it’s here on a broader level and how that became known is not quite clear, but it’s visible signs reveal themselves in the vineyards, experts say.
Whitman College Director of Geology Kevin Pogue counted himself among those surprised by its discovery.
He offers a whole session on phylloxera and its history as part of his autumn lessons.
“I’ve been teaching that class at Whitman for 10 or 12 years,” he said. “Whenever I’ve taught it, I would always say, ‘And we don’t have it here.’”
Although the louse is native to North America, the sandier and siltier soils of the Walla Walla Valley are not typically conducive to its spreading, Pogue said.
In other wine regions — including the French and California vineyards where the devastation had previously taken place — the solution to vine longevity came from replanting or grafting healthy plants onto roots of American vine.
Replanting entirely may be cost prohibitive and unnecessary, Pogue said. But a transition to grafted vines appears to be on the long-term horizon. In that, lies opportunity to thoughtfully strategize around rootstock.
“Just as there are different varieties grafted on and cloned, there are many, many different rootstocks,” he said.
“There’s some positive opportunities that could present themselves.”