Washington Grape Grower Battles New Threat

A virologist with Washington State University’s (WSU) Viticulture and Enology program has discovered a block of ‘Grenache’ vines are stunted and sickly because they suffer from a damaging syndrome caused by Tobacco Ringspot Virus (TRSV), a pathogen never before seen in Washington.

“That was a huge surprise,” says Naidu Rayapati. “It was a revelation that we have a new problem here.”

Grapes from healthy ‘Grenache’ vines dwarf grapes from vines damaged by Tobacco Ringspot Virus.
(Photo: WSU).

The problem was initially discovered by Vineyard Manager Andrew Schultz on grapevines planted in a former pear orchard near Wapato, WA. The ‘Grenache’ vines had been productive and healthy, but over time, a mysterious infection had taken hold.

Mottled, stunted, and sickly, the infected vines were producing only tiny, miniature clusters — or no fruit at all. Infected leaves, crisscrossed with white lines, looked as if they had been munched by insects, but Schultz could see no bugs.

“It was unlike anything I’d seen before,” Schultz says. “You should take a look at this,” he told Rayapati, his former professor and an expert on grapevine diseases at WSU’s Irrigated Agriculture Research and Extension Center (IAREC) in Prosser.

Discovered 90 years ago in Virginia, TRSV affects a wide variety of crops, from grapes, apples, and cherries to common weeds. It is spread by nematodes — specifically, the dagger nematode, Xiphinema americanum. Like the virus, this species of dagger nematodes was also previously unknown in Washington.

Rayapati and Schultz aren’t sure how the virus and its nematode vector arrived here, but Rayapati suspects they may have hitched a ride with pears or other crops years ago.

TRSV causes vines to become totally unproductive with time.

“In about 10 years, you lose everything and the land becomes useless,” Rayapati says. “It’s a very serious problem.”

Since that first discovery, in 2013, the virus remains isolated on that single vineyard block in Wapato. Rayapati, his team of graduate students, and Schultz have been working together on techniques to contain and defeat it.

Grape growers typically get rid of viruses by removing infected plants and replacing them with healthy, virus-free ones.

“Tobacco Ringspot is a totally different beast,” Rayapati says. “Removing and replanting doesn’t stop it.”

That’s because the virus also infects the dagger nematodes living in the soil, and those creatures are difficult to kill.

Chemicals can kill the nematodes, but daggers are hardy, and their populations spring back within a season or two.

Rayapati’s research has shown that the dagger nematode species in this vineyard block can spread TRSV from infected to healthy grapevines.

Teja Narta, a postdoctoral researcher, and Daniel Hottell, and undergraduate intern at Washington State University, collect soil samples to identify dagger nematodes in a vineyard affected by Tobacco Ringspot Virus. (Photo: WSU)

Rayapati and Schultz are testing different combinations of rootstocks and grafts, as well as own-rooted vines, to find grape plants that resist the virus or are unpalatable to nematodes. Schultz is also looking at predatory nematodes that eat the ones spreading the virus.

Right now, the best defense against TRSV is knowing when you’re at risk.

“TRSV has a broad host range, and can jump easily from one plant species to another. That’s why we’re trying to alert growers,” Rayapati says. “If you’re planning to switch crops, it’s a good idea to get your soil tested to see if you’re at risk of these nematode vectors.”

“We’re farming 50-year-old pear blocks that predate modern clean plant materials, and may someday go to grapes,” Schultz says. “We don’t know what viruses may be in the ground that do not affect pears, but may pop up when we go to grapes.”

WSU IAREC is home to the Clean Plant Center Northwest, which helps growers plant virus-free trees, grapes, and hops. Rayapati urges growers to always plant clean vines from a reputable source, reducing their risk of accidentally spreading a virus.

“Once you introduce these diseases, the rest is history,” he says.

Rayapati also urges growers to meet and talk about virus defense.

“On Red Mountain, for example, where grape acreage is expanding, we’re trying to assemble growers of new and existing plantings to discuss the risks,” he says.

Wine is a $4.8 billion industry in Washington. Sixty thousand acres of wine grapes are grown here, with more planted every year.

“It’s important to nip this problem in the bud,” Rayapati says. “Tobacco Ringspot isn’t something that will wipe out the industry, but we need to make sure growers plant virus-free materials and there are no risks in the soil itself.”

For Schultz, researching the virus means saving not just his vines, and the investment they represent, but the Northwest industry — for years to come.

“We could take the vines out and replant with something else, or just fallow the land,” Schultz says. “But, with Naidu, we’re providing answers to other growers who may run into this virus.”

Soil testing is available commercially, and Rayapati’s team offers plant testing services. Learn more at the WSU IAREC website and through the WSU Viticulture and Enology website.

 

Topics: , ,

Leave a Reply

One comment on “Washington Grape Grower Battles New Threat

  1. Sharing the misery, free trade not so free ,any way might have to switch crops or may try trap crops for nematode hatching .

Grapes Stories
Grapes
October 24, 2017
Little Winegrape Loss from California Wildfires
University Extension experts give an update of the destruction, potential for smoke taint in wine. Read More
Grapes
October 13, 2017
Fairgrounds Host California Fire Evacuees
Gallo will contribute $1 million to fire recovery effort and will match employee donations two-for-one. Read More
Grapes
October 10, 2017
Wildfires Hit California Wine Country
California Gov. Jerry Brown declares state of emergency for northern counties impacted by flames. Read More
Grapes
October 7, 2017
Tips for Effective Vine Mealybug Management in Grapes
Scouting, trapping, and mating disruption can help prevent populations of this pest increasing in your vineyard. Read More
Grapes
September 26, 2017
New England Researchers Study Viability of Seedless Table Grapes Varieties
University of New Hampshire project looks at growing systems, varieties to determine what type of production would be suited for cooler climates. Read More
Grapes
September 12, 2017
Heat Wave Leads to Early Winegrape Harvest in California’s Sonoma County
Ask any winegrape grower to describe the grape harvest in Sonoma County and you typically hear “harvest time is like Read More
Grapes
September 8, 2017
Spotted Lanternfly Population Large This Year
Thanks to mild winter, numbers for the pest are growing, especially in southeast Pennsylvania. Read More
glass of red wine
Grapes
August 30, 2017
ASEV Confirms Enologist as President
Washington State University’s James Harbertson to lead American Society for Enology and Viticulture (ASEV) as the 2017-2018 president. Read More
Grapes
August 26, 2017
Ode to Being a Part-time Farmer [Opinion]
I work with many grape growers in Virginia. Some of them work full time at a single vineyard operation. Many Read More
GenNext Growers
August 8, 2017
Winegrape Society Awards $100,000 in Scholarships
American Society for Enology and Viticulture bestows awards at its 68th national conference. Read More
Grapes
July 7, 2017
California Winegrowers Applaud $5 Million to Battle Disease
Governor approves Pierce’s Disease Control Program money for the first time since 2011. Read More
Grapes
July 3, 2017
Climate Doesn’t Weigh Heavy On Ste. Michelle Wine Estates
While warming trend has been a part of past few seasons, the vineyard is incorporating new technologies to grape growing versus altering production techniques. Read More
Grapes
July 3, 2017
How to Handle Warming Pacific Northwestern Vineyards
The warming temperatures in the Pacific Northwest are well-suited for red winegrape production, but other changes in viticulture practices must be made. Read More
GenNext Growers
June 29, 2017
Cornell Graduate Student Earns Grape Disease Research
Doctoral candidate recognized by American Society of Enology and Viticulture for work studying sour rot pathogens. Read More
Grapes
June 29, 2017
Cornell University Wants You to Name That Grape
Contest to name cold-tolerant variety a seedless ‘Concord’-type berry runs through July 31. Read More
The Latest
Grapes
November 8, 2017
California Winegrowers Report Excellent …
Wine Institute: Strong quality across the state as ample rain ended drought. Read More
Disease Control
October 31, 2017
Novel Biofungicide Approved for Grapes, …
Marrone Bio Innovations says new product has proven highly effective for controlling downy mildews and white molds. Read More
Grapes
October 30, 2017
New Smartphone App Advises Grape Growers
Up-to-date information on what products can be used to solve a problem is available right there in the vineyard. Read More
Grapes
October 24, 2017
Little Winegrape Loss from California Wi…
University Extension experts give an update of the destruction, potential for smoke taint in wine. Read More
Grapes
October 13, 2017
Fairgrounds Host California Fire Evacuee…
Gallo will contribute $1 million to fire recovery effort and will match employee donations two-for-one. Read More
Grapes
October 10, 2017
Wildfires Hit California Wine Country
California Gov. Jerry Brown declares state of emergency for northern counties impacted by flames. Read More
Grapes
October 7, 2017
Tips for Effective Vine Mealybug Managem…
Scouting, trapping, and mating disruption can help prevent populations of this pest increasing in your vineyard. Read More
Grapes
September 26, 2017
New England Researchers Study Viability …
University of New Hampshire project looks at growing systems, varieties to determine what type of production would be suited for cooler climates. Read More
Grapes
September 12, 2017
Heat Wave Leads to Early Winegrape Harve…
Ask any winegrape grower to describe the grape harvest in Sonoma County and you typically hear “harvest time is like Read More
Grapes
September 8, 2017
Spotted Lanternfly Population Large This…
Thanks to mild winter, numbers for the pest are growing, especially in southeast Pennsylvania. Read More
Grapes
August 30, 2017
ASEV Confirms Enologist as President
Washington State University’s James Harbertson to lead American Society for Enology and Viticulture (ASEV) as the 2017-2018 president. Read More
Grapes
August 26, 2017
Ode to Being a Part-time Farmer [Opinion…
I work with many grape growers in Virginia. Some of them work full time at a single vineyard operation. Many Read More
GenNext Growers
August 8, 2017
Winegrape Society Awards $100,000 in Sch…
American Society for Enology and Viticulture bestows awards at its 68th national conference. Read More
Grapes
July 7, 2017
California Winegrowers Applaud $5 Millio…
Governor approves Pierce’s Disease Control Program money for the first time since 2011. Read More
Grapes
July 3, 2017
Climate Doesn’t Weigh Heavy On Ste. Mich…
While warming trend has been a part of past few seasons, the vineyard is incorporating new technologies to grape growing versus altering production techniques. Read More
Grapes
July 3, 2017
How to Handle Warming Pacific Northweste…
The warming temperatures in the Pacific Northwest are well-suited for red winegrape production, but other changes in viticulture practices must be made. Read More
GenNext Growers
June 29, 2017
Cornell Graduate Student Earns Grape Dis…
Doctoral candidate recognized by American Society of Enology and Viticulture for work studying sour rot pathogens. Read More
Grapes
June 29, 2017
Cornell University Wants You to Name Tha…
Contest to name cold-tolerant variety a seedless ‘Concord’-type berry runs through July 31. Read More