Northern Grapes Project: Assessing Bud Injury and Adjusting Pruning

April 3, 2014
Terence Bradshaw, UVM Tree Fruit and Viticulture Specialist

I am forwarding this from the Northern Grapes Project mailing list. LOTS of great information to consider as you get into your dormant pruning. In cold years like this one, it is critical to do some bud counts before pruning. -TB

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Assessing Bud Injury and Adjusting Pruning

After the extreme cold temperatures much of the US experienced this winter, many grape growers are concerned about winter injury to buds and trunks. Here in the Finger Lakes region of New York, for example, up to 90% of the primary buds on some V. vinifera cultivars were killed.

Cold-hardy University of Minnesota and Swenson cultivars can withstand much colder temperatures than most other grapes, but it’s still advisable to assess your grapes for winter damage before pruning, and adjust your bud number accordingly. If more than 20% of the buds are dead, you’ll want to leave more buds to maintain a normal cropping level.

Here are some online resources to explore to learn more about how to assess winter injury and manage winter-damaged vines.

Assessing Winter Cold Injury to Grape Buds

Cornell University, Pool and Martinson

(http://www.fruit.cornell.edu/grape/pool/winterinjurybuds.html)

Includes photos of live vs. dead buds, information on how many extra buds to leave when pruning, and links to videos that explain how to evaluate bud damage.

Evaluating Bud Injury and Adjusting Pruning

Cornell University, Martinson

(http://blogs.cornell.edu/nnygrapeupdate/2014/02/28/evaluating-bud-injury-and-adjusting-pruning/)

Blog post with instructions for assessing damage and managing damaged vines.

Cold Injury in Grapevines

eXtension.org, Chien and Moyer

(http://www.extension.org/pages/63372/cold-injury-in-grapevines#.UzwTDPldWJc)

Includes photos of damaged buds and trunks, as well as links to other good resources.

Evaluating Grape Bud Damage Prior to Winter Pruning

Colorado State University, Caspari and Larsen

(http://agronomy.unl.edu/c/document_library/get_file?uuid=912db951-022b-487e-9823-fbb8b5835523&groupId=4128273&.pdf)

This document has photos of the same bud as a series of cuts is being made. This will help you learn what’s too shallow, what’s just right, and what’s too deep.

Ohio Grape-Wine Electronic Newsletter, Special Issue 17 January 2014

Ohio State University, Dami

(http://www.oardc.ohio-state.edu/grapeweb/images/OGEN_17_Jan_2014_Dami.pdf)

Contains information on how to assess for bud damage, how to adjust pruning, and links to other resources. Also includes the article “Pruning Grapevines after Winter Injury” that Dr. Imed Dami wrote for “Wines and Vines” trade magazine a few years ago.

Anatomy of Grapevine Winter Injury and Recovery

Cornell University, Goffinet

(http://www.hort.cornell.edu/goffinet/Anatomy_of_Winter_Injury_hi_res.pdf)

This is a long, and quite technical paper, but has a lot of good photos and in-depth information, including how vines are constructed, what tissues are susceptible to cold, the process of vine cold acclimation, a description of cold injury in the various organs, and the mechanisms the vine uses to heal (if possible) cold-injured structures.

Chrislyn A. Particka, PhD

Extension Support Specialist

Cornell University

Department of Horticultural Sciences

630 W. North Street

Geneva, NY 14456

cap297

315-787-2449 (desk)

315-787-2216 (fax)

www.northerngrapesproject.org

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The UVM Tree Fruit and Viticulture Program is supported by the University of Vermont Agriculture Experiment Station, a USDA NIFA E-IPM Grant, and USDA Risk Management Agency Funds.

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