Wines & Vines Home
   
 
Welcome Guest
LOGIN |  CREATE ACCOUNT
 
ADVERTISEMENT
 
 
 
02.16.2012  
 

Does Nitrogen Cause Pinot Leaf Curl?

Researchers analyze mystery ailment at Sonoma County Grape Day

 
by Andrew Adams
 
 
Pinot Leaf Curl
 
Pinot Leaf Curl, a disease that can cause stunted leaf development and even kill shoots and nodes, has been striking Pinot Noir, Pinot Blanc and Pinot Meunier vines with greater severity in recent years. Photos from Rhonda Smith
Santa Rosa, Calif.—In the past three years, the vine sickness Pinot Leaf Curl has struck more often and with greater severity in Sonoma County’s valuable Pinot Noir vineyards.

The ailment also can affect Pinot Blanc vines and has been observed less frequently in Pinot Meunier. Pinot Leaf Curl, or PLC, appears during spring; symptoms can range from stunted or distorted leaf growth to severe instances in which an entire shoot and node can die.

Rhonda Smith, University of California extension advisor for Sonoma County, made the ailment a focus of Sonoma County Grape Day on Feb. 16. She said she wanted to draw attention to the sickness and explore a possible relationship between the disease and nitrogen. She said the disease, which has been found in every Pinot Noir region of California, is known to be more common during cold, wet springs.

Dr. Doug Adams, a professor of viticulture with UC Davis, joined Smith on the panel. Adams said that when vines enter dormancy, they store nitrogen to support growth in the coming spring and summer. When the growing season arrives, the plants convert the stored nitrogen into a form that can be metabolized by the plant. The nitrogen compounds used during this process can also yield putrescine. Elevated levels of putrescine can be toxics to vines, he said.

Is putrescine the culprit?
The next step, Adams said, is to find a 100% asymptomatic Pinot vineyard and determine “normal” levels of nitrogen compounds. Then researchers can evaluate if symptomatic tissues contain elevated levels of putrescine. “You can find putrescine in most plants, but only in trace amounts,” Adams said.

Various terms have been used to describe PLC. Smith said the condition was known, but it has not been a major problem until recent years, when Sonoma County growers began to become concerned by the increased incidence and severity of symptoms.

Smith said the condition can reduce crop loads, but it was hard to discern how much of an effect it may have had on the 2011 harvest totals because of losses from botrytis and other, more common pests.

Smith also wanted to draw growers’ attention to the fact that while PLC can sometimes look like botrytis, it is a wholly separate condition. She said PLC first weakens tissue, and then opportunistic botrytis finds a way to attack the vine. Therefore, Smith stressed that fungicide applications do not work on PLC.

There appears to be some variation in clonal susceptibility for PLC: When present in a vineyard, the condition tends to be found in mature blocks, and mild symptoms can occur in up to 80% of vines, Smith said.

Symptoms to watch
According to a report written by Smith, symptoms of PLC can range from mild to severe. Onset occurs early in the growing season, most commonly when three or more leaves separate from the shoot tip. The leaves then appear to “bend or fold downward across the middle of the blade, perpendicular to the main vein”—hence the descriptive “leaf curl” name. The vines will appear to have “broom-like growth” with multiple lateral shoots pushing at all nodes, with abnormal leaves until a single lateral becomes dominant.

Mild symptoms are often limited to darkened or necrotic regions on the underside of leaves. In a severe case of PLC, the necrotic region will extend to the petiole: Both the blade and petiole abscise from the shoot. If that is a cluster-bearing node, the disease can reduce crop load.

Sonoma Grape Day is an annual event for grapegrowers, organized by UC Cooperative Extension and sponsored by the Sonoma County Winegrape Commission.

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  
July 2015 $603 million
6%
$8,136 million
6%
July 2014 $568 million $7,701 million
     
Direct-to-Consumer Shipments » Month   12 Months  
July 2015 $66 million
9%
$1,906 million
14%
July 2014 $61 million $1,674 million
     
Winery Job Index » Month   12 Months  
July 2015 323
4%
262
18%
July 2014 312 222
     
 
MORE » Released on 08.13.2015
Direct To Consumer
Wine Shipping Report
2015
 
Download full report »
 
 

FEATURES
 

Practical Winery & Vineyard Library
 
Search the PWV archive »
 
 

CALENDAR
  • September 6
     
    Harvest Wine Celebration
     
  • September 11-13
     
    Cincinnati Food + Wine Classic
     
  • September 17
     
    Winejobs.com Summit
     
  • September 18
     
    Owning and Operating an Urban Winery or Brewery
     
  • MORE »
 

READER COMMENTS
 
Article: Crowd Funds 10,000 Cultivars »
 
Thanks for interviewing the academic breeders. They would love to be able to raise $167K...
Reader: New York Viticulture
 
Article: Nielsen Unpacks Package Design »
 
Okay, I'll state the obvious (to anyone with CPG experience) - the Wine Biz is...
Reader: Joel Miller
 
Article: Nielsen Unpacks Package Design »
 
Very interesting reading. Certainly agree with the more indirect approach of evaluating the extent to...
Reader: Roger Brooks
 
Article: Experimental Solution to Pierce's Disease »
 
Congratulations to the team! It is amazing what can be done with biological controls. Keep...
Reader: Bruce Coulthard
 
Article: The Spiciest Wines You Have Ever Tasted »
 
There are some wines from New Mexico are infused with pepper flavors. Also, The Wine...
Reader: Guest
 
 


2015 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
 Wine Club Director
 Willamette Valley, OR
DTC, Tasting Room and Retai
 Experienced Wine & Spi...
 Northern California, CA
Sales and Marketing
 Wine Educator
 Oakville, CA
DTC, Tasting Room and Retai
 Housekeeper
 Los Olivos, CA
General Administration and
 Bottling Line Technici...
 Napa, CA
Cellar, Lab and Production
 National Sales Manager
 Salem, OR
Sales and Marketing
 Sr. Compliance Special...
 Santa Rosa, CA
General Administration and
 Office Assistant
 Oakville, CA
General Administration and
 Business Relationship ...
 Manteca, CA
General Administration and
 Wine Sales Representat...
 Los Angeles, CA
Sales and Marketing
 
More Job Listings >>
Follow Us On:
 
 





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

Advertise  |  Site Map  |  Contact Us  |  Privacy Policy
 
 
Copyright © 2001-2015 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.