Wines & Vines Home
   
 
Welcome Guest
LOGIN |  CREATE ACCOUNT
 
ADVERTISEMENT
 
 
 
11.20.2013  
 

Update on Red Blotch Disease in Grapevines

Cornell professor details the virus for Napa wine grape growers

 
by Paul Franson
 
 
Alternative text
 
A Pinot Noir vine that has become infected with red blotch disease.
 

Napa, Calif.—There was standing room only as growers and winemakers skipped the wine reception at the Nov. 13 Napa Wine + Grape Expo to hear the latest intelligence on red blotch virus from Dr. Marc Fuchs of the Department of Plant Pathology at Cornell University in Geneva, New York.

Fuchs preceded his talk by acknowledging that viticulturists don’t have all the answers yet; many questions remain about the newly identified virus, its transmission methods and ways to overcome it. Fuchs presented a similar presentation during an event hosted by the University of California, Davis' Foundation Plant Services. A video and slide show of his presentation can be found here.

Majority of growers have seen it
A show of hands of growers and vintners who see signs of red blotch in their vineyards was asked for. Most in the room raised their hands, a sign of the malady’s spread in Napa Valley and elsewhere. Fuchs said he’d get the same response among New York grapegrowers.

The symptoms of red blotch disease – more formally, grapevine red blotch associated virus (GRBaV) – were first described in 2008, and transmission by grafts was confirmed in 2012. The virus was also recognized that year, and an assay was developed to detect and confirm it. The first potential vector was identified this year. That short time line contrasts with 80 years to take those steps with leafroll virus and 120 years with fanleaf virus.

The symptoms of the virus are red blotches and spots on leaves, though a small percent (2.5%) of infected vines don’t show any symptoms likely because of the latency of disease onset. The red ranges from pink to crimson. (Editor’s note: further description of GRBaV, numerous photos by Dr. Fuchs and others, and a short list of labs that can test for the virus can be viewed here.) Other viruses like leafroll also color leaves, but GRBaV displays a different pattern of red than leafroll does.

“Red blotch can dramatically affect quality,” said Fuchs. Red blotch virus delays ripening. It can lead to 5 or 6 lower Brix in mature grape berries. It also affects the anthocyanins and can lead to reduced color in red grapes and their wine.

Fuchs mentioned the challenge of confirming that the phenomenon met the criteria for a disease, a problem partly because viruses won’t grow in petri dishes, but only in their host. Nevertheless, researchers have found that GRBaV causes red blotch.

‘Test, don’t guess’
Unfortunately, he notes, your eyes aren’t enough to identify the virus. Polymerase chain reaction (PCR) assays are available to identify the virus. Tests can identify presence of the virus in any tissue of the vine – leaf, petiole, dormant canes or clusters at any time of year. Because of the difficulty of confusing symptoms of the virus with other viruses, he said, “Test, don’t guess.”

He said that research suggests that there may be two variants of the virus. Red blotch virus can be found in both red and white wine grapes, in table grapes, raisin grapes and rootstocks. So far, it’s been detected in wine-growing regions in California, Oregon, Washington, BritishColumbia, Virginia, Pennsylvania, Maryland, New Jersey, New York and Ontario.

Red blotch virus is spread by propagation and grafting, and anecdotal evidence suggests it may spread by other means. The Virginia creeper leafhopper (Erythroneura ziczac) seems to be able to transmit red blotch virus from vine to vine in the greenhouse, but it’s not yet proven that the leafhopper is a vector in the field.Fuchs says that at this point, the best way to manage the disease is to select planting material carefully.

Micro-shoot tip culture, used to eliminate other viruses from vines, works with GRBaV but only in 24% of the time, so it is inefficient. The same technique works more than 80% of the time for fanleaf and leafroll viruses, Fuchs added. You can remove the individual infected vines (“roguing”) or replace the whole vineyard. He suggests replacement if more than 25% of vines are infected.

At this point, he doesn’t recommend using an insecticide as there’s no proof that any insect is a vector. One proposed remedy doesn’t work. “There’s no need to sterilize equipment. Viruses can’t be transmitted by mechanical means in vineyards like pruning equipment,” he said, though that can help with bacteria, insects and other pests.

Work on the virus is supported by the American Vineyard Foundation, California Grape Rootstock Research Foundation and New York Wine and Grape Foundation.

 

SHARE »
Close
 
Currently no comments posted for this article.
 
CURRENT NEWS INDEX »


 
Wines & Vines Home
 
866.453.9701 | 415.453.9700 | Fax: 415.453.2517
65 Mitchell Blvd., Ste. A San Rafael, CA 94903
info@winesandvines.com
Wine Industry Metrics
 
Off-Premise Sales » Month   12 Months  
March 2013 $546 million
5%
$6,988 million
7%
March 2014 $572 million $7,451 million
     
Direct-to-Consumer Shipments » Month   12 Months  
March 2013 $177 million
20%
$1,483 million
10%
March 2014 $213 million $1,634 million
     
Winery Job Index » Month   12 Months  
March 2013 253
15%
166
27%
March 2014 292 210
     
 
MORE » Released on 04.14.2014
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Practical Winery & Vineyard Library
 
Search the PWV archive »
 
 

Direct To Consumer
Wine Shipping Report
2014
 
Download full report »
 
 

CALENDAR
  • April 23
     
    Sustainable Vineyard Practices: Strategies for Using Less Water
     
  • April 23-26
     
    CABs of Distinction in Paso Robles
     
  • April 26
     
    Siera Pelona Valley wine festival
     
  • April 27
     
    TAPAS Grand Tasting
     
  • MORE »
 

READER COMMENTS
 
Article: Starbucks Expands Wine Sales to More Cities »
 
Pretty amazing that the 1st wines chosen are from Argentina, Italy, and New Zealand! I...
Reader: Jacques Brix
 
Article: Starbucks Expands Wine Sales to More Cities »
 
Given Starbucks commitment to sustainability and global responsibility, I expect this move could be a...
Reader: Guest
 
Article: What to Do About Red Blotch »
 
There is NO correlation with planting density. Also FPS is working on the problem. New...
Reader: Guest
 
Article: Premiere Wine Auction Nets $5.9 million »
 
Thanks for letting us know Janet, we've updated the story. Cheers
Reader: Andrew Adams
 
Article: Will Barrels Go the Way of Floppy Disks? »
 
Fun piece. Particularly enjoyed the three clearly superior attributes of standard barrels, including looking cool...
Reader: Tom Gable
 
 


Directory/Buyer's Guide — Your Wine Industry Marketplace
 
 
WINERY SEARCH
 
 
Advanced Search »
SUPPLIER SEARCH
   by Product
 by Company Name or Brand
 
Browse by Category »
2014 Directory/Buyer's Guide
The Wines & Vines Directory and Buyer's Guide
 
 
EXPANDED ONLINE SEARCH INCLUDED WITH PURCHASE
 
ORDER NOW »
 
LEARN MORE »
 
 
Wines & Vines Magazine
 
 
LEARN MORE »
 
SUBSCRIBE »
 
Digital Edition Now Available!
Wines & Vines Digital Edition Now Available
 
LEARN MORE »
 
ORDER NOW »
 
 
The Wines & Vines Online Marketing System
 
The Industry Standard winery marketing application
 
FREE LIVE DEMO »
 
VIEW VIDEO »
 
 
 
 
Latest Job Listings
 Sales Person
 Metro Boston / North Shore, MA
Sales and Marketing
 Accountant/Bookkeeper
 Healdsburg, CA
Finance
 Vip & Trade Coordinato...
 Sonoma, CA
DTC, Tasting Room and Retai
 Pricing Systems Analys...
 San Francisco, CA
Finance
 Fine Wine Sales Repres...
 Seattle And Portland, OR
Sales and Marketing
 Maintenance Mechanic
 Healdsburg, CA
General Administration and
 Wine Sales South Bay
 Santa Clara, CA
Sales and Marketing
 Full Time Retail Wine ...
 New York, NY
DTC, Tasting Room and Retai
 Harvest Intern
 Yamhill, OR
Winemaking and Production
 Office Manager
 Napa, CA
General Administration and
 
More Job Listings >>
Follow Us On:
 
 





Home  |  About Us  |  Editors  |  Subscribe  |  Print Edition  |  Digital Edition

Advertise  |  Site Map  |  Contact Us  |  Privacy Policy
 
 
Copyright © 2001-2014 by Wine Communications Group, Inc. All Rights Reserved.
No material may be reproduced without written permission of the Publisher.
Wines&Vines does not assume any responsibility for any unsolicited manuscripts or materials.