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WSU’s Voice of the Vine- Clean Plants, Taste Washington, Maritime Grapes

Posted by | March 26, 2014

At the root of healthy vineyards

Before a glass of Washington wine is poured, before the vine is planted or even arrives at a certified nursery, scientists at the Clean Plant Center Northwest in Prosser, Wash., make sure plants are ready to grow bacteria and virus-free in Pacific Northwest vineyards.

Ken Eastwell, director of the Clean Plant Center Northwest, and his team propagate plant material and screen it for disease-causing bacteria and viruses, giving it a plant “check up,” so to speak. When Eastwell first began his career in the medical field, he worked with animal viruses such as human polio and pancreatic viruses in salmon. He was breeding plants on the side. Figure 1

“I started wondering if some of the techniques I was using in medicine would work in plants,” he said. “At the time, the science of virology in plants seemed to be lagging behind.”

Back in the 1940s and 50s, the tree fruit industry was not sustainable because the industry was losing so many trees to viruses that it struggled to remain profitable, Eastwell said. Originally established as a trial program, the predecessors of the Clean Plant Network focused on tree fruit, but in 1961, a clean plant program for grape vines was initiated.

Plant clean, stay clean

Considerable scientific expertise and rigor is needed to thoroughly screen plant material for viruses and to propagate clean plant material. The clean material is then released to certified commercial nurseries throughout the Pacific Northwest where it is grown under regulated conditions and routinely tested, before it is sold to growers.

Just one of two regional services in the United States, WSU’s Clean Plant Center Northwest grows over 270 clones of grapes and is regularly adding more. Every plant that goes into the foundation vineyard is first indexed repeatedly and, if necessary, “cleaned” of viruses by tissue culture. After tissue culture, another year of testing required before the grapes are planted in the foundation vineyard. If clean, they are then released to registered nurseries for further propagation and sale. The grapevines are also sold directly to growers.

“In a way, we are a victim of our own success,” Eastwell explains. Sixty or so years ago, the cost of removal and replacement of diseased trees and the lost yields during the replacement process placed a huge burden on farms, he said, and the quality of fruit wouldn’t be tolerated by consumers today.

“Clean plant programs reversed this tide,” he said. “We now have a new generation of growers that have no personal experience dealing with the environment prior to the creation of these programs. The overall health of orchards and vineyards has improved dramatically.

Plants get sick, too

Still, the last thing any grower wants is a diseased vineyard and damage to their crop, so WSU Extension viticulturist Michelle Moyer is spreading knowledge — especially to those just getting started growing grapes — to help prevent the spread of disease. Eastwell and Moyer recently presented a poster at the Washington Association of Wine Grape Growers in Kennewick and won an award for their presentation titled, “How Clean is Clean?”

WSU researchers can now screen for grapevine red blotch, which causes red coloration of leaves and a reduced yield in fruit harvest.
WSU researchers can now screen for grapevine red blotch, which causes red coloration of leaves and a reduced yield in fruit harvest.

“Vines can sometimes become infected while out in the field, but it’s important to start off clean,” Moyer said. “The biggest impact of disease is during their early stages of vineyard development, but if you plant a healthy plant, it will be robust plant.”

Identifying new diseases

Two new viruses have been reported in the last two years thanks to the work of virologists and researchers — grapevine red blotch-associated virus and grapevine vein-clearing virus. The team at the Clean Plant Center Northwest then went to work to ensure that none of the plants being offered by the program were infected with these viruses.

“Of course, we can’t test for what we don’t know,” says Moyer, but the team does currently screen for 22 diseases, including the two recently identified viruses. And with faster, more affordable technology becoming available, plus an awareness of planting clean plants, growers and plant virologists can continue to support a healthy future for wine grapes.

For more on clean plants, visit or subscribe to Viticulture and Enology Extension News (VEEN) for an upcoming feature by Michelle Moyer on plant quarantines. 
Note: Eastwell will be recognized for his role in advancing the USDA APHIS National Clean Plant Network and as Director/Plant Pathologist of the Clean Plant Center-Northwest at the annual American Phytopathological Society meeting August 9-13 in Minneapolis, MN.

-Rachel Webber

A taste of Washington: Meet the makers

Every March, Taste Washington is invitation for wine lovers and foodies, winemakers, chefs, and restaurateurs to eat, drink and learn about regional cuisine and wines from the Pacific Northwest. See what’s in store for this year’s Taste Washington at CenturyLink Field Event Center in Seattle, Wash., March 29-30. Be sure and stop by the Washington State University exhibit to talk with current students including, Margeaux Goodale, Ryan Strong, Ashley Johnson, and Les Walker. Until then, meet a few Washington State University students, friends, and alumni working to bring premium wines to the table:


Tiffany Britton (’11)  |  Enologist  |  Claar Cellars

Partnerships with two-year schools have created opportunities for students like Tiffany Britton. She entered the WSU Viticulture and Enology Program to learn more about wine science after taking an introductory course at Yakima Community College. A horticulture graduate, Britton is now an enologist at Claar Cellars. “It’s not all glamour when you are knee-deep in wine dung, but when you are pouring at an event like Taste of Washington, you feel like a superstar because you helped create the product.”



Linn Francis Scott  |  Winemaker  |  Sparkman Cellars

Enthusiasts who have toured the international wine circuit recognize the unique opportunities made possible through WSU. Linn Francis Scott studied internationally in France and Germany, but was drawn to Washington after meeting Thomas Henick-Kling, and later performing research on Riesling for Chateau St. Michelle Wine Estates. His next venture includes a Ph.D., with the aim of developing complex flavor mappings for Washington wines.



Joel Perez (’14)  |  Apprentice  |  Fidélitas Wines

Californian Joel Perez found a wine program that matched his tastes after being drawn to Washington’s thriving industry. After launching a red blend and a Riesling under the WSU Blended Learning wine label, Perez is now developing a Cabernet blend. His passion is only beginning to mature; he will pursue a master’s degree this fall, exploring clonal differences during fermentation. Perez explains, “Imagine if clonal grapes yielded different aromatic and phenolic traits brought about by purposeful changes during fermentation—the outcome would be tremendous.”


Grow wine grapes in western Washington

WinePubThinking about growing wine grapes in Western Washington? Look no further than the latest wine science publication from WSU Extension by Michelle Moyer, available for free at:

There are many aspects to consider in order to be successful at growing grapes in the maritime climate areas of the Pacific Northwest. Typified by cool summers, mild winters, and variable precipitation throughout the growing season, these climate condition resemble those of classic wine grape regions of Europe such as Champagne and Burgundy in France, the Ahr and Franconia areas of Germany, Vinho Verde in Portugal, and the areas on Lake Geneva and Lake Zurich in Switzerland. This suggests that maritime PNW has potential for producing grapes and wine types similar to those areas.Quality wine grapes can be grown in western Washington, provided careful consideration is give to choosing the appropriate site, variety, rootstock, and cultural practices.