Ohio Grape-Wine Electronic Newsletter

Editor: Imed Dami, PhD
Assistant Professor, Viticulture Specialist
Department of Horticulture and Crop Science
Ohio Agricultural Research and Development Center
1680 Madison Avenue
Wooster, OH 44691-4096
Phone: (330)-263-3882
Fax: (330)-263-3887
E-mail: dami.1@osu.edu
 www.oardc.ohio-state.edu/grapeweb/
 

 

26 July 2006
 
 
===========================================================
 Content:
 
Spring Frost Update Revisited
New Grape Varieties Released
Crop Estimation
OGIC New Website
Renown Viticulturist Remembered
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 Spring Frost Update
By Imed Dami, HCS-OARDC

I participated at a growers meeting in Northeast Ohio on 16 June 2006 organized by David Marrison and sponsored by OGIC. The purpose of the meeting was to share updates from the severe spring frost experienced in that region in April and May; followed by a session of questions and answers from grape growers.  David Scurlock shared pictures and data taken from our research vineyard in Wooster. Greg Johns from AARS was in attendance as well and shared his observations from our research vineyard in Kingsville. David Marrison gave also an update on the temperatures data collection from participating vineyards and shared that data with me. Here are summary of my comments and recommendations to participants and growers who were not able to attend:
 
- Following berry set, growers had a better estimate of potential yield in 2006 and resulting crop loss. Many have overestimated crop losses, which varied with grape type and varieties. Concord was the worst hit and sustained probably the highest crop loss. At OARDC-Wooster, in April, I estimated 90 % bud damage in Concord (see 2 May O-GEN issue). After berry set, many shoots originated from the basal buds (see attached pictures) and cluster count averaged 28 per vine (normal is 160 clusters/vine) or 83% reduction. Hybrids with fruitful secondary and base buds faired better even with severe frost damage. For example spring frosted Vidal would still produce a normal crop. Losses from vinifera grapes varied with site and variety.
- Temperature records of more than 30 vineyard blocks in the area did not show a specific pattern or trend and absolute elevation did not help in many instances (high-elevation vineyards did not fair better). This again shows the importance of relative elevation (elevation relative to surrounding area).
- High relative humidity may have worsened the extent of bud damage. Wet buds are few degrees less hardy than dry buds.
- Tips to keep in mind after frost: reduce or avoid nitrogen fertilization; more time and labor on canopy management due to high vegetative growth and low fruit production; more rigorous disease and insect management program due to excessive foliage and resulting shading; and earlier harvest than normal due to light crop.

Cornell Releases Three New Wine Grapes
By Joe Ogrodnick, Cornell University

(Editorial comments by Imed Dami: All three cultivars have been evaluated in the past few years in our research vineyards here at OSU-OARDC in collaboration with Dr. Bruce Reisch from Cornell University; and wines have been made by Todd Steiner. Our findings from Ohio are communicated to Dr. Reisch and the summary below reflects observations from trials throughout the eastern region. This project is still in progress with more new advanced and promising selections being tested at OARDC. Our newest plantings of NY winegrape selections took place last year.)

Cornell University officially named and released three new wine grapes during the 31st annual American Society for Enology and Viticulture/Eastern Section Conference and Symposium, held July 9-11 in Rochester, N.Y. The three new grapes-'Noiret'™, 'Corot noir'™ and 'Valvin Muscat'™-were developed and tested by Bruce Reisch, grape breeder and professor of horticultural sciences at the New York State Agricultural Experiment Station in Geneva, N.Y., in cooperation with Thomas Henick-Kling, professor of enology at the Experiment Station and leader of Cornell's enology program. "All three grapes are broadly adapted to the wine growing regions in the East, and produce high quality varietal wines that are superior to those currently available to Eastern growers today," said Reisch.

'Noiret'™ (pronounced "nwahr-ay"),(Formerly NY73.0136.17) a mid-season red wine grape, is a complex interspecific hybrid resulting from a cross made in 1973 between NY65.0467.08 and 'Steuben'. 'Noiret'™ represents a distinct improvement in the red wine varietal options available to cold-climate grape growers," said Reisch. "Wines are free of the hybrid aromas typical of many other red hybrid grapes. The distinctive red wine is richly colored and has notes of green and black pepper, with raspberry and mint aromas, and a fine tannin structure." Care should be taken to grow 'Noiret'™ on sites less susceptible to extreme winter temperatures and downy mildew, noted Reisch.

'Corot noir'™, (Formerly NY70.0809.10) a mid- to late-season red wine grape, is a complex interspecific hybrid resulting from a cross made in 1970 between Seyve Villard 18-307 and 'Steuben'. 'Corot noir'™ is a distinct improvement in the red wine varietal options available to cold climate grape growers," said Reisch. "Wines are free of the hybrid aromas typical of many other red hybrid grapes, and can be used for varietal wine production or for blending. The distinctive red wine has a deep red color and attractive berry and cherry fruit aromas."

'Valvin Muscat'™ (Formerly NY62.0122.01) is a mid-season white wine grape with a distinctive muscat flavor and aroma that is desirable for blending as well as for varietal wines. The complex interspecific hybrid grape resulted from a cross made in 1962 between Couderc 299-35 (an interspecific hybrid known as 'Muscat du Moulin') and 'Muscat Ottonel'. "Valvin Muscat'™ is recommended for the production of high quality muscat wines," said Reisch. "Vines are well suited to good grape growing sites in the Eastern United States, and should only be grown on suitable rootstocks." Some care should be exercised to control disease, and fruit should be picked when the muscat flavor reaches its peak, he noted.

'Noiret'™, 'Corot noir'™ and 'Valvin Muscat'™are the seventh, eighth and ninth wine grapes respectively to be released by the Experiment Station. Previous wine grape releases from Cornell include: 'Melody', 'Horizon', 'Cayuga White'(grown widely throughout New York and beyond), 'Chardonel' (now the number two grape in Missouri), 'Traminette'(quickly gaining in popularity throughout the East), and GR7 (used in red wine blends).

Vines of the three new grapes are available from licensed commercial nurseries. Contact B.I. Reisch <bir1@nysaes.cornell.edu> for a list of sources. Commercial nurseries may be licensed by contacting Cornell Research Foundation, 20 Thornwood Drive, Suite 105, Ithaca New York 14850 (phone: 607-257-1081; fax: 607-257-1015; email <des33@cornell.edu>).

For pictures of these varieties: http://www.nysaes.cornell.edu/pubs/press/current/060707Grapes.html
 
 

Methods of Crop Estimation in Grapes
By Imed Dami, HCS-OARDC

Crop estimation also called crop prediction is the process of projecting as accurately as possible the quantity of crop that will be harvested.  Why estimate the crop?  Obviously, growers need to know how much crop they produce and whether their vines are overcropped or undercropped in order to conduct the necessary crop adjustment by cluster thinning. Vintners would also like to know how much fermentation tank space is needed.
 
            At the 2005 Ohio Grape-Wine Short Course, Rick Hamman, Viticulturist at Hogue Cellars, gave an excellent talk on how they estimate crop at the winery. Crop estimation methods include ‘eyeballing’, seat of pants, and more rigorous and methodical protocol.  Basically, he indicated that, based on his experience, the quick and less rigorous methods gave the worst crop estimates.
 
In this article, I will summarize two methods considered to be the most accurate and popular in most viticultural regions across the country. Both methods provide only an “estimate” of yield which should never be considered “final”.
 
Method 1: Traditional Method
 
            This method relies on determining the average cluster weight at harvest in one season and uses that number to estimate yield in the following season. The following formula can be used to estimate yield:

 

PY = (ANV x NC x CW) / 2000

Where:
PY = predicted yield (tons per acre)
ANV = actual number of vines / acre
            NC = number of clusters per vine
            CW = cluster weight (in pounds).
 
According to the formula, the grower needs to measure 3 parameters each year; the actual number of vines per acre, the number of clusters per vine, and the cluster weight.  These parameters are discussed below with examples.
 
Actual number of bearing vines per acre:
The maximum number of vines per acre is determined by the row and vine spacing.  For example, a spacing of 6 x 9 feet vineyard will have 807 vines per acre.  Almost always the “actual number” is lower than the “maximum number” of vines per acre due to missing vines for several reasons such as diseased vines (crown gall), winter-injured vines, replanting, etc.  For these reasons, each year, growers need to physically count the missing vines, subtract the number from the maximum number to get an accurate count of bearing vines.  If 5% of the 807 vines/acre (i.e. about 40 vines) were missing or nonbearing then the actual number of bearing vines/acre is 767.
 
  1. Number of clusters per vine:
This number will depend on how many nodes (buds) are left after pruning.  Counting clusters per vine can be determined as soon as they are visible (before bloom) or as late as pre-veraison.  The advantage of early count is that clusters are readily visible and are not obscured by leaves. This information is also needed by vintners so they can plan on the quantity to purchase from each grower.  The number of vines on which to count clusters depends on vineyard size and uniformity.  For example, in 1 to 3 acre-vineyard with vines of a uniform age, size, and pruned to the same bud number, only 4% of the vines need to be counted.  In practice, a minimum of 20 vines is counted. Growers need to bear in mind that the higher the number of vines selected for cluster count the more accurate the yield estimate will be.  In larger, non-uniform vineyards, more vines should be selected.  All the clusters on the sample vines should be counted.  Also, the vines should be selected methodically; e.g. select every 10th vine in every other row.
 
  1. Cluster weight:
It is the component of yield that varies the most from year to year.  It is affected by environmental conditions.  For example, wet weather during bloom could cause poor set and may lead to low cluster weight; also a dry summer tends to reduce berry size and thus may decrease average cluster weight.  Other factors that may affect cluster weight include cultural practices (irrigation, fertilizers), diseases, insects, and birds.  Cluster weight at harvest is a key part of any yield prediction program.  The goal of obtaining cluster weight at harvest is not to predict the yield that year, but to provide records for yield prediction in subsequent years. AT HARVEST, it is best to sample clusters from vines rather than from bins.  The same vines used for cluster counts could be used for cluster weights.  Average cluster weight is obtained by sampling at least 100 clusters throughout the vineyard, weigh the total, and divide by the number of clusters sampled.  Growers who do not have these data (hopefully will in the future) may use estimates of cluster weights shown in the following table.
 
  1. Example: Crop estimation of Cabernet franc
  2.         Spacing = 6 x 9 feet or 807 vines/acre
  3. Missing/nonbearing vines = 5% or about 40 vines/acre
  4. Actual number of bearing vines: 807 - 40 = 767 vines/acre
  5. Average cluster count = 40 clusters/vine
  6. Average cluster weight = 0.23 lbs
  7. Predicted yield = (767 x 40 x 0.23) / 2000 = 3.5 tons/acre.
 
 
Average cluster weight (in pounds) of common grape varieties
 
Variety
 
 

 
Cabernet franc
0.23
 
Concord
0.30

Chambourcin

0.42
 
Chardonnay
0.23
 
Chardonel
0.36
 
Marquis
0.50
 
Pinot gris
0.22
 
Lemburger
0.30
 
Neptune
0.53
 
Riesling
0.18
 
Niagara
0.35
 
Seyval
0.43
 
Traminette
0.24
 
Vidal blanc
0.34
 
 
Method 2: Lag Phase Method
 
            This method is based on collecting cluster weights during the “lag phase”. The lag phase corresponds to the time when seeds begin to harden, which is also the period when berry growth slows temporarily. Typically, the lag phase occurs about 55 days after first bloom which corresponds to the accumulation of 1000-1300 growing degree days (GDD) or heat units. GDD of 1200 is the benchmark time for many varieties. In general, at the lag phase, berries have reached about 50% of their final weight. Thus a measurement of average cluster weight at the lag phase can be multiplied by an “increase factor” or “multiplier” of 2 to predict cluster weight at harvest. In other words, this method is based on the premise that cluster weights will double from the lag phase to harvest. The multiplier “2” varies among varieties and seasons. In future estimation, you have to determine your own multiplier for each variety. To perform the lag phase method, the following information is needed:
 
  1. Number of bearing vines per acre: same as in traditional method
  2. Number of clusters per vine: same as in traditional method
  3. Cluster weight at lag phase: weigh 100-200 representative clusters per acre or block during the lag phase.  This phase typically occurs 55 days after first bloom.
  4. GDD can be obtained from weather stations near your vineyard. The information is readily available on weather websites. Another alternative is to use OSU-GDD calculator website by entering your zip code at: http://www.oardc.ohio-state.edu/gdd/
  5. Use the following the formula to estimate yield at harvest:
 
 

PY = (ANV x NC x Lag CW x 2) / 2000

 
Where:
PY = predicted yield (tons per acre)
ANV = actual number of vines / acre
            NC = number of clusters per vine
            Lag CW = cluster weight at lag phase (in pounds).
 
 Bottom Line:
 
-  Best to use one method or the other rather than doing nothing. Crop estimation is a “MUST” in viticulture regions producing quality grapes and wines. If you have never conducted crop estimation, begin this year. It is never late.
-  In general, 70% of the variation in yields comes from year-to-year variation in the number of clusters per vine, and 30% from year-to-year variability in cluster weight.
-  Consider a good estimate if it is within 15% of the actual yield.  Do not get discouraged if first attempts at crop estimation are inaccurate, because the more experience and data acquired, the more accurate the estimates will become. 
-  MAINTAIN RECORDS OF CLUSTER WEIGHTS FROM YEAR TO YEAR IN ORDER TO IMPROVE ESTIMATION.
 

OGIC Unveils New Website
Christy Eckstein, OGIC

As the stature of Ohio wines continues to grow, the OGIC has increased its marketing support with the launch of a multifaceted marketing campaign to promote the quality and value of Ohio wines across the state. The OGIC is promoting Ohio wines through print ads, Internet advertisements, two new television commercials, and a new web site (www.tasteohiowines.com).  This new web site allows visitors to search Ohio wineries by region, winery name, and nearest city and then receive a map and directions from their location to the winery/wineries of their choosing. The web site also contains detailed information ranging from how to entertain with wine and where to purchase Ohio wines to how to grow grapes in Ohio and the latest news and events about Ohio’s wine industry. For more information about Ohio’s growing wine industry, visit www.tasteohiowines.com today.


 Viticulturist, Dr. Pool, Remembered:
by Joe Ogrodnick, Cornell University

GENEVA, NY: Robert M. Pool, professor emeritus of viticulture at Cornell University, died at his home on Saturday, June 10, after a long illness. Over the course of his distinguished career, Pool's research, extension work and teaching contributed significantly to the science and practice of viticulture, and positively influenced New York's wine and grape industries.

"Throughout Bob Pool's career, he provided leadership in areas of viticultural research that had many positive impacts on the New York wine industry," said Thomas J. Burr, director of the New York State Agricultural Experiment Station in Geneva, N.Y. "His work elevated the stature of viticulture at Cornell and earned him the respect and friendship of grape researchers worldwide. Bob will also be remembered as a highly effective and caring teacher and mentor who touched the lives of many Cornell students."

Pool's primary research interests included: mechanization of pruning, crop level as it affects grape and wine quality, sustainable viticulture, vineyard floor management and weed control, the effects of cultural practices and rootstocks on cold hardiness, interaction of disease (fungal, bacterial and viral), and vine productivity.

Pool was active in developing national grape germplasm repositories at Davis, California, and Geneva. He formed, and, for 10 years, chaired the Grape Commodity Advisory Committee to the National Plant Germplasm Committee. He served on the advisory committees of New York's regional grape extension specialists, on Cornell University's statewide fruit extension committee, and was an active participant in writing extension publications, organizing research tours and presentations, and training extension agents.

In July of 1997, Pool received the Cantarelli Prize for 1995-96 from the Italian Academy of Vine and Wine. The award was given in recognition of Pool's outstanding and original contributions to research in the mechanical regulation of crop load and fruit quality in grapes, as well as the impact and consequences of his work on the reduction of production costs for the vine and wine industry.

"Bob always managed to balance industry needs with practical trials involving varieties and clones new to the region as well as other trials involving viticultural practices that could be easily implemented in area vineyards," said Dave Peterson of Swedish Hill Winery. "His work on mechanical pruning and thinning changed a method that had first appeared to be short-termed and headed toward running a vineyard into the ground, into a more sustainable practice. His insight into practices that incorporated quality and economic reality were all-encompassing and led to solutions that helped industry not only survive in difficult times, but prosper."

"Viticultural research has been a vital part of the New York grape industry's evolution, and Bob Pool has been a leading force in that area," said Jim Trezise, president of the New York Wine and Grape Foundation. "His projects have covered a very broad range of issues of importance to grape growers, and the results of his research have been published in parts of the world well beyond New York."

Pool was born in Sacramento, California in 1940 and grew up in the San Francisco Bay Area. He graduated from the University of California, Davis with degrees in enology and food science, received his Ph.D. in pomology from Cornell in 1974 and joined the Cornell faculty as an assistant professor of viticulture. He was named professor in 1988. He was a member of the American Society of Viticulture and Enology, International Society for Horticultural Science, and the American Society for Horticultural Sciences.

Pool recently realized a lifelong dream by opening his own vineyard and winery, Billsboro, in Geneva, N.Y., which features several varietals. He was proudest of his Pinot noir wines, made from a clonal selection based on his research.

Pool was an active member of the Presbyterian Church, in Geneva, where he sang in the choir, served several terms as Elder and chaired the Mission Committee. He also enjoyed singing with the Community Chorus and the MLK Choir. He will long be remembered as a generous host and gourmet cook who loved sharing good food and wine with friends and family.

Pool is survived by his wife of 25 years, Jennifer Morris, his sons Ron and Alex of Geneva, his daughter Margaret (Bruce) Mills of N. Palm Beach, FL; two sisters, Margaret Baker of Castro Valley, CA; and Judy (Jack) Langdon of Knaresborough, England; three grandchildren, several nieces, nephews and great nieces and nephews. He was pre-deceased by his parents and a sister Shirley.

Memorial contributions may be made in Pool's name to the Mission Committee Fund for Youth Mentoring, care of the Presbyterian Church, 24 Park Place, Geneva, N.Y. 14456.