WSU’s First Certified-Organic Wine Grape Vineyard Harvests First Study on Weed Control
As vineyard acreage in western Washington continues to increase, more farmers seek strategies for controlling weeds, especially in new vineyards. Heightened interest in organic wine grape growing on the west side also has growers looking for certified-organic weed control methods. Researchers Carol Miles and Tim Miller and graduate student Callie Bolton from WSU’s Northwestern Washington Research and Extension Center in Mount Vernon completed a two-year trial of sustainable weed control management on WSU’s first certified-organic vineyard.
The 2.5-acre vineyard was planted in 2009 in order to conduct research in organic wine grape production and disease management for local growers considering an organic operation. But weed control eclipsed other concerns, according to WSU Extension vegetable specialist Miles.
“Weed management in new wine grape vineyards was identified by local growers and winemakers as the primary constraint to establishing organic production in the region,” Miles said.
Two early ripening wine grape varieties, Pinot Noir Precoce and Madeleine Angevine, grow at the Mount Vernon vineyard. There, Miles, Miller, and Bolton studied several weed-control treatments recommended by local growers and winemakers: rototilling and mowing; in-row cultivating with a Wonder Weeder, a new vineyard cultivator produced in Burbank, Washington; and planting in-row and between-row cover crops of winter wheat and winter peas, and a combination of the two.
Preliminary results showed that the cover crops were perhaps too effective because they not only competed against the weeds, but also with the young grape plants, Miles said. “All cover crop treatments tended to reduce shoot growth (new vine length), vine pruning weights, and change in vine diameter of both grape cultivars.”
When a vineyard is being established in the first three years, this competition is undesirable. Later, however, it’s important for maintaining a healthy balance between fruit load and vine growth, said Miller, a WSU Extension weed scientist. Grape vines tend to grow too thickly—at the expense of the grape clusters. “De-vigoring,” or slowing down excessive vine growth, helps keep that balance.
“In western Washington vineyards, cover cropping might be an excellent tool to use for weed management once vines start to produce fruit,” Miller said, “but probably not early in the life of a vineyard, when one wants fast establishment and lots of vine growth.”
Miles added that while it is likely best not to have in-row cover crops for a newly established vineyard, a comparison with cover crops planted only between rows was not included in their study. “So we cannot say that cover crops overall should be avoided during the establishment years.”
Rototilling and mowing between rows and hand weeding within rows were still the best weed control strategies for the vineyard, according to Miles and Miller. The Wonder Weeder provided good in-row weed management, but it may also cause significant damage to first-year vines, whose thinner trunks can’t withstand the cultivator’s tripping mechanism. Miller noted that the Wonder Weeder would probably work better when the vineyard’s plants are mature, with thicker trunks and well established root systems.
Others participating on the weed management study were research associate Jonathan Roozen and technical assistant Jacqueline King, both from WSU Mount Vernon NWREC; and Mercy Olmstead, assistant professor of ag-horticultural sciences at the University of Florida in Gainesville.
Starting this year, Miles and her colleagues are fielding two more studies on organic wine grapes. The first, being conducted at a commercial vineyard, will evaluate the cost effectiveness of four newer organic fungicides for control of grape powdery mildew. The second will explore whether replanting or retraining is a better recovery method in a severely injured young vineyard after freezing, an apt trial considering that the Mount Vernon vineyard lost 30 percent of its plants due to freezing last November.
– Nella Letizia
Learn more about WSU’s West Side research and extension by visiting http://bit.ly/wsumtv.
Scientist Discovers New Horizons… Just across the Parking Lot
Climb a tall mountain, hike a long trail, move to a different part of the world–these are a few of the ways people commonly make major changes in their lives. Not Richard Larsen. He walked across the parking lot.
Larsen is the recently hired research winemaker at Washington State University’s Irrigated Agriculture Research and Extension Center in Prosser. After 21 years a virologist with the U.S. Department of Agriculture, based on the Prosser campus across from the WSU facilities, Larsen crossed the parking lot to work for WSU. For the USDA, he studied viral pathogens of important legume food crops, including beans, peas and chick peas, and lentils, as well as studying soil-borne pathogens of alfalfa.
“But I’ve always been fascinated by wine,” Larsen said. When he was a kid in Portland, Oregon, he and his sister would investigate the morning-after remains of dance parties hosted by his parents in the family’s basement. “We went down searching for goodies—chips and such. There were glasses with the dregs of wine, too. In those days, it must have been rosé. In any case, it was disgusting!”
Later, the future scientist attended college at San Jose State University in the San Francisco Bay Area. “I majored in music performance,” Larsen said. Another turn in the research winemaker’s journey: he was a clarinetist and vocalist before turning to what would be his bread and butter, plant pathology.
In San Jose, though, and later at Cal Poly San Louis Obispo, where he earned a master’s degree in agriculture specializing in plant pathology, Larsen discovered California wine. Starting sometime in the late 1960s and developing over the course of the ’70s, Americans discovered they had a taste for premium European-style wines. Sweet, fruity pop wines gave way to big Cabernets and oaky Chardonnays.
Soon after Larsen took the virology position with USDA in Prosser, he met Sara Spayd, who served as WSU’s enology Extension educator for 26 years before returning to her native North Carolina. (In fact, they likely crossed paths, Larsen recollects, when they were both at the University of Arkansas in Fayetteville, where Larsen was earning his Ph.D. in plant science.) “Sarah had sensory experiments going, so she needed trained volunteers for tastings.” Enologists, like other food scientists, train volunteers in order to get a group of tasters whose palates are educated enough to detect small differences in taste in otherwise similar samples.
Through that volunteer training, Larsen discovered that he had a rare gift: he could detect not just small but truly minute differences in wines that most of us would say were from the same bottle. “That really got me going, so I started reading enology research papers.”
When Spayd returned to North Carolina, WSU’s current enologist, Jim Harbertson, joined the wine science team. “We hit it off right away. Jim has an amazing palette, so there is the enological friendship. And then there’s Manchester United… We’re like a couple of kids with baseball cards when it comes to soccer,” Larsen said.
Harbertson and his colleagues designed a 5,000-gallon research winery – the largest in the Pacific Northwest. The project was ambitious, but necessary: in order to serve the burgeoning wine industry, grapes needed to be grown and wine needed to be made under conditions mimicking those encountered by commercial growers and vintners. Even if on a smaller scale, though, the winery is too much to handle for the small group of wine scientists in Prosser. A winemaker was needed to manage the multitude of experiments the team wanted to conduct.
“My plant pathology background was a big help,” Larsen said. “I already knew the importance of sanitation and understood how important the control of variables is in the scientific method.” It’s control of variables that make Larsen’s job even more complicated than a commercial winemaker’s. “There are lots of little iterations in what we do. Instead of a big vat of one thing, we have 10 vats, each one with just one different variable.”
Among the issues being addressed by WSU’s wine scientists are questions of fruit maturity. In a region with a short growing season, knowing with scientific precision what difference the maturity of grapes has on the final product is critical. Likewise, pinpointing the effects of different pH regimes on a wine’s phenolics (its color, aroma and flavor components) is important, as acidity influences the taste of wine. These are just two of the projects the team is working on that have ramifications for wine quality. Others include plant pathologist Naidu Rayapati’s project on Grapevine leafroll virus and its effect on fruit, and a project with viticulturist Markus Keller, who is investigating a variety of water management issues.
“There are some incredible levels of expertise on this team,” Larsen said. “Certainly some of the best in the country – if not the world.” Larsen said he loves coming to work. “I’ve read all those winemaking research papers over the years, but there’s nothing like working side by side with these people and learning by osmosis. It’s stimulating to the mind.”
Larsen’s palate is in big demand, not just at the Prosser campus. Larsen joins Thomas Henick-Kling, director of WSU’s program in viticulture and enology, in offering sensory seminars teaching professionals how to detect faults in the wines they are making, hopefully in time to make corrections. Larsen also sometimes serves as a judge at wine competitions. “When you’re tasting 20 or 30 big Cabs, your palate just gets worn out.” Larsen suggested a bite of roast beef to cleanse the mouth of tannins, or even a swig of beer, which has the same effect.
When asked how an aspiring winemaker might develop such a keen palate, Larsen said, “Drink lots of wine! Seriously, swirl, sniff and sip with others who really enjoy wine–and talk about what you’re tasting.”
– Brian Clark
Time for a career change? Check out WSU’s professional certificate programs in grape growing and winemaking at http://bit.ly/wsuvecert or our Bachelor of Science programs in viticulture and enology: http://bit.ly/9Xy6iI.
Learn more about WSU’s research winery in Voice of the Vine: http://bit.ly/r62pDV.
An article featuring Sara Spayd ran in Voice of the Vine here: http://bit.ly/9sPXRl.
Hello, Old Friend, Where Have You VEEN?
WSU Extension viticulturist Michelle Moyer and her colleagues have just published a new issue of VEEN: The Viticulture and Enology Extension Newsletter. Among many useful articles in this issue is one by Moyer with the melancholy title, “Where was Summer?” It has gone the way of La Niña. As Moyer observes, though, “If grape production were easy, we wouldn’t define wine by the vintage.” True enough; and if it were easy, we wouldn’t need science-based solutions for the issues faced by growers and winemakers. In any case, 2011 is looking to be a great vintage, even if the harvest is a bit on the small side.
This issue of VEEN has updates on measuring Brix, the WSU V&E certificate program, wine sensory science and much more. Grab your copy (it’s free!) here: http://bit.ly/wsuveen.
And while you’re at it, grab a couple of other free publications by Moyer and her colleagues from the WSU Extension publications web site (where most publications are available as free downloads). Moyer pointed out two new ones of special interest to Voice of the Vine readers.
The first is “Botrytis Bunch Rot in Commercial Grape Production,” which is sure to be a reluctant hit in the wake of such a damp summer. Point your browser to http://bit.ly/wsuvebbr and click the “download PDF” link to get your copy.
The other new pub is likewise pertinent: “Assessing and Managing Cold Damage in Washington Vineyards.” Learn how to determine if cold temperatures have damaged your vines, as well as ways to avoid such problems. You’ll find that guide here: http://bit.ly/pC5grC.
-Brian Clark
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