Phylloxera comes to Colorado, and the wine industry holds its breath

By Bart Taylor | Dec 11, 2016

The wine sector is the crazy old uncle of Colorado's prolific beverage industry. A wealthy uncle to be sure, with fertile bottomland, magnificent crops and impressive factories. Eccentric to the point of being a bit standoffish, miffed by the sudden success of brewing and distilling nephews, his mood's improved lately. A burst of creativity -- ciders and canned wines -- has captured the public's imagination.

But a new development threatens the good vibe. Phylloxera, killer of grape vines and destroyer of industries, has been found in Mesa County, center of Colorado's wine kingdom. Suddenly the industry is holding its breath.
Phylloxera's an aphid-like insect, a pest, native to North America but most famous for decimating French vineyards in the mid-nineteenth century and laying waste to Europe's wine industry as a result. No one's sure how it got to Europe, but it's certainly made its presence felt in America as well. In 1992, phylloxera ravaged 50,000 acres in Napa Valley, half the total vines in the region. As the New York Times described:

In 1992, the scene across the Napa Valley was desolate. In what had been some of the most beautiful vineyards in the world, piles of dead vines pulled from the soil were being burned. The pall of black smoke mirrored the mood of winemakers, who watched grimly as their lifeworks went up in flames.

Is it possible Colorado vineyards might suffer the same fate? I had a lengthy conversation with Dr. Horst Caspari, CSU State Viticulturist, about the discovery of phylloxera and its possible impact on the sector. Caspari and I have spoken before. When I reached him on the phone, he chuckled. "I guess I know why you're calling." A scientist, Caspari measured his assessment.

"It could be very very serious, or not, depending on what we find in the coming days and weeks. Is it a single incident, involving one or two vineyards that we can quarantine, or, do we find as we look at other vineyards that it's widespread? We simply don't know." Regarding the offending vine, he was quick to note, "Of course, it's been pulled and burned." Visions of Napa.
Or not. "Phylloxera has been found in the wild grapes of Colorado's canyons -- it's native to North America," said Caspari, but the recent development is jarring. "It's the first time it's been found inside a viticultural area, within a commercial vineyard in our main production area." Caspari speculated it might have been introduced from vines coming from out-of-state nurseries, from new plantings of "cold-hardy" varieties growers and winemakers here favor for their resistance to Colorado's intense weather. But it's impossible to be sure, at least today.
The million-dollar question is what impact a widespread outbreak would have on grape production. Caspari is confident that even in a worst case scenario, where the aphid has spread to vineyards outside the current location, the damage can be limited. "There may be only a small reduction in overall output, if any," he says. Lessons from past outbreaks help. Rootstocks today are generally more disease resistant, as are younger vines, and this spring new plantings from recent years will be coming online.
Growers are also better equipped to deal with an outbreak today than in years past. "We simply have much better chemistry," said Caspari. "We'll be able to get insecticides into the root systems next spring, and if there's more infestation than we know of now, and again we don't know, we can also set traps that will catch the insects as they emerge in the spring to let us know where those infestations are."
But even though the probability of an industry-wide calamity is "very, very low", vineyard owners and wine brands that grow grapes stand to be affected -- if the phylloxera outbreak is more widespread than currently known. For an industry comprised of lot's of small operators, even a 15 to 20 percent hit to production for vineyards and brands across the valley could be devastating. Today any financial liability would be "on the grower's backs," suggested Caspari, "even though they didn't do anything wrong."
We'll know more soon. Caspari's team is gathering more samples this week in an effort to assess the problem before ground freezes. Vineyard owners are wary. "They're understandably nervous about bringing contaminated objects into their vineyards from our shoes, or whatever, but we're obviously taking every precaution," he emphasizes. "Plus there's no reason to go into a vineyard that's thriving."
If there's a silver lining, even from a small outbreak, it's that Colorado's industry may benefit long-term, from best-practices and new vines. In California, wineries "benefited from the disaster by rectifying errors they had made and by taking advantage of the latest research on new grape clones, planting density and the compatibility between rootstocks and the vines grafted to them," the New York Times reported. "They learned about new kinds of vine trellises and how to orient the vines to get the best combinations of sun and irrigation."
Asking wineries to consider the upside of an industry-changing event, is too much, today. Isolating the pest and the problem and limiting the financial hit to Colorado operators is the outcome Caspari and industry allies are working toward this winter.
Bart Taylor is publisher of CompanyWeek. Contact him at