Humans love California Cabernet and Merlot, but unfortunately, a leafhopper insect called the sharpshooter has a taste for the stuff as well. When it nibbles on vines, it infects them with a bacterium that causes Pierce’s disease, a huge problem in the vineyard. The disease, which can cost California’s grapegrowers more than $100 million per year, can kill a vine in as little as two years and has no known cure. Scientists and growers have been trying to do something about it for decades, and now, Napa winery Whitehall Lane, along with some top viticulture experts in the state, may have a solution: Entirely new grapes.
Dr. Andrew Walker of the University of California at Davis has been experimenting for two decades to develop new grape varieties that are highly resistant to the disease; he's been joined by Dr. Paul Skinner of Vineyard Investigations in Napa Valley. They thought they found two winners in Camminare Noir and Paseante Noir, and the Whitehall team joined forces with them, planting them in 2016.
"Mainstream grape varieties like Cabernet and Merlot are slowly being decimated along riparian areas," explained Katie Leonardini, Whitehall Lane vice president of operations; numerous wineries in prime areas such as Napa and Sonoma have such land along a river or stream. "Our Oak Glen vineyard borders a creek in the Oak Knoll AVA. Pierce’s disease has affected yields and overall vine health [here], eventually killing some vines"—between 50 and 100 vines each year, on average. "We have 165 vines to replace in 2021 due to Pierce’s disease."
The disease blocks water flow to leaves and stresses the vines until they die. Most growers must rely on insecticide to manage the sharpshooters, but Leonardini’s father, Tom, wanted to go a different, more ecologically friendly route. New varieties, if successful, could be planted as a buffer zone in the vineyard for Cabernet. They could also be tasty enough to blend and bottle themselves, which is exactly what Whitehall has done with its 2019 Camminare Noir and 2019 Paseante Noir.
Camminare Noir is a cross of Petite Sirah and Cabernet Sauvignon, while Paseante Noir is bred from Zinfandel, Petite Sirah and Cabernet Sauvignon. Winemaker Jason Moulton reports positive results, both in the vineyard and bottle, comparing both to Cabernet in terms of taste. "The tannin profile and extraction is quite impressive when comparing [them] to mainstream varieties," he said. He found some other fascinating qualities too, like the ability to develop high sugar levels during ripening while still maintaining ideal physical structure. "Some Cabernet Sauvignon or Merlot will call it quits early and start to turn to raisins, while these varieties continue to ripen with very little raisining or breakdown," he said. "They can get up to 28 to 30 Brix and taste like honey as a flavor profile, yet still sit on the vine looking vibrant and plump."
For now, there are fewer than 25 cases of each of the new wines, but Leonardini is thinking big-picture in terms of innovation, vineyard health and sustainability in the state. "Our hope is that this catches on in Napa Valley and other areas that suffer from Pierce’s disease."
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