Ohio Grape Electronic Newsletter

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Content:
 
New listserv for O-GEN
Grape-Wine Day on 19 Aug
Crop Estimation of Grapes
Grape Berry Moth
Time for Petiole Sampling 
Nitrogen Fertilization
Grapes Wanted/for Sale
Upcoming Events -- workshop 3

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New Listerv for O-GEN
By Dr. Imed Dami, OARDC

More and more people are joining our mailing list to receive our electronic newsletter (O-GEN). The good news is this is great that we have a positive feedback and that the content of the newsletter is informative and timely. The bad new is, managing the list "as is" has become challenging. So the O-GEN mailing list has been moved to an Ohio State University ListServ computer.  This will allow more efficient sending and delivery of the newsletter, and will insure one uniform, up-to-date, list of subscribers.

To subscribe to the OGEN mailing list, send me an email: dami.1@osu.edu with your name and email address; both are needed to subscribe to the list. Note that subscribers are not able to send (or reply) to the OGEN list, they only receive mailings. As always, suggestions and comments are welcome.


Ohio Grape and Wine Day
by Greg Johns, Ashtabula Ag. Research Station

August 19, 2005(Friday)
2:30 - 5 p.m.
Twilight Tour Following
Ashtabula Agricultural Research Station
2625 South Ridge East
P.O. Box 467
Kingsville, OH 44048
440-224-0273

For more information contact:
Greg Johns
440-224-0273
johns.1@osu.edu
http://www.oardc.ohio-state.edu/grapeweb/
From CLEVELAND: Take I-90 East to exit 235; north one mile to St. Rt. 84; west one mile to Ashtabula Agricultural Research Station.
From YOUNGSTOWN: Take St. Rt. 11 north to I-90 East to exit 235; north one mile to St. Rt 84; west one mile to Ashtabula Agricultural Research Station.
From ERIE: Take I-90 West to exit 235; North one mile to St. Rt 84; west one mile to Ashtabula Agricultural Research Station.
Ohio Grape & Wine Day is FREE and open to the public.
There will be a charge for the Twilight dinner tour.

Immediately following the OG&WD will be tours of Conneaut Creek area, South Ridge Vineyards and
Markko Vineyard.  The program features presentations by Ohio State University experts on grapes, wine, insects and diseases.
• Introductions.
• 2005 insect situation update.
• Cabernet Franc:
• Planting and trellis construction.
• Training systems.
• Clonal selections.
• Pinot Noir: Crop load study.
• Pruning and leaf pulling.
• Disease update.
• Winter injury update.
• Demonstration of netting installation.
• Roundup safety for sucker control in vineyards.
• Yellow nutsedge control with Sandea.
The Twilight tour dinner (attached) will be at Markko Vineyard for an additional charge.
Please call OSU Extension at 440-576-9008to make reservations.


Crop Estimation of Grapes
By Dr. Imed Dami, 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 adjustment. Vintners would also like to know how much fermentation tank space is needed.
 
The method described here is simple and has been used successfully in other winegrape growing regions. Growers interested in trying this method should begin collecting data this season.  This method provides only an “estimate” of yield which should never be considered “final”.  Components of yield vary each year depending on the year, site, variety, and cultural practices.  The following formula can be used to estimate yield with reasonable accuracy:
 



 

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.
 
1) 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.
 
2) 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.
 
3) 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. MAINTAIN RECORDS OF CLUSTER WEIGHTS FROM YEAR TO YEAR IN ORDER TO IMPROVE ESTIMATION.
 
4) Example: Crop estimation of Cabernet franc
        Spacing = 6 x 9 feet or 807 vines/acre

 
Even with thorough sampling, accurate vine counts, and many years of average cluster weight data, the actual crop tonnage at harvest can vary significantly from that which is predicted. 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. 




 

Average cluster weight (in pounds) of common grape varieties

 
Variety                                         cluster weight (lb)

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
 
 

Grape Berry Moth
By Dr. Roger Williams and Dan Fickle, OARDC

At this time of year it is very important to control one of the most important grape pest in Ohio the grape berry moth (see attached).  Pheromone trapping has indicated a new generation is emerging and control strategies should be considered. Remember, this generation is the one that does the most damage to the maturing fruit and facilitates bunch rots.  Good control can be achieved with the pyrethroids and insect growth regulators just remember that these compounds can loose their effectiveness quickly if appreciable rain is experienced after application.  The addition of a spreader sticker can help to gain a few extra days of control.  Follow label instructions on rates and harvest intervals.  Table grapes are already starting veraison so many of you growing for the fresh market may only get one more treatment applied for control of this pest. Those of you growing later maturing grape cultivars may need to make at least two applications between now and harvest to assure good late season control of grape berry moth.  Pesticide recommendations may be obtained from the 2005 Midwest Commercial Small Fruit Spray Guide which is available on line at http://www.ag.ohio-state.edu/~sfgnet/. 


Time for Petiole Sampling
By Dr. Imed Dami, OARDC

Fertilizer needs can be determined by 3 ways: observing visual symptoms, using soil tests, and using tissue (petiole) analysis. Because each method had advantages and limitations, all 3 should be checked on a regular basis. Petiole analysis is one of the best tools available to monitor the nutrient status of your grape varieties. Unfortunately, grape producers do not often use it.  Tissue analysis serves two purposes: determine the nutrient status of the vine; and identify a suspected nutrient deficiency observed in the vineyard.  By using tissue analysis, growers have a better handle on their fertilizer program and usually end up cutting costs since fertilizers are applied only as needed.  Attached are answers to commonly asked questions about petiole analysis.


Foliar Nitrogen Fertilization
By Dr. Tim Martinson, Finger Lakes Extension Viticulturist , Cornell University

Clusters have a fairly high N demand around veraison.  Foliar-applied urea (or other foliar feeds containing N) applied a few times around veraison can increase yeast-assimilable nitrogen (YAN), particularly when drought has limited N uptake from the soil.  In our trials over the last few years, we have used up to 10 lb urea in 100 gallons (5 lb actual N) without burning the foliage.  This is not a panacea for eliminating Atypical Aging (a wine defect associated with limited N uptake in drought years in white wines), but has had a secondary role (the more major effect occuring with irrigation) in reducing ATA.  It is effective in bumping up the YAN values. This may help winemakers avoid stuck fermentations.  It does not appear to prolong or 'restart' shoot growth, nor delay wood maturation.


Grapes Wanted/For Sale
By Donnie Winchell, Executive Director, OWPA

I have received a few requests about electronic listing of grapes wanted or for sale. Many wonder whether Ohio has such a service. The answer is YES and I am sending this note so that all recipients would know and can inform others about the service. This service is provided through the website of the Ohio Wine Producers Association (OWPA), and I have contacted Donnie Winchell regarding this topic (Editor's note). She has gratefully provided the following article:

OWPA has a very informal service for grower and winery members and as well as for others in the industry.  If anyone has grapes and/or juice and/or wine cellar or vineyard equipment for sale [for commercial needs or just homewinemaker lists], send the information to OWPA ASAP.  It will be posted on our web site and e mail blasted [the commercial quantities at least] to the other state marketing offices around the country. Ditto for wineries looking to purchase fruit or juice.  This is a free service.  We have dozens of calls in the summer and fall from homewinemakers and our web site attracted nearly 100,000 unique visitors last year. Here is the contact information: http://www.ohiowines.org/; or winchell@knownet.net or 440-466-4417.00-22440-46
 

Up-coming Events
by David Scurlock, OARDC

 

Grape-Wine Workshop Series

 
The Grape-Wine Program at the Department of Horticulture and crop Science at OARDC is offering a series of workshops. Topics will include current situation in vineyards and questions regarding grape growing and wine making in Ohio. Imed Dami, Viticulturist, Dave Scurlock, Viticulture Assistant, and Todd Steiner, Extension Enologist will be present to answer your questions. We encourage you to attend and bring your questions with you regarding your vineyard/winery operations. Also, take this is opportunity to visit commercial vineyards and wineries and interact with the winemakers. For your convenience, you can choose the location closest to you to attend. We look forward to seeing you there.
 
 
What:   Question and Answer Session
                Vineyard tour and current practices
        Winery tour
 
Where:  Raven’s Glenn Winery (see map)
                56183 County Road 143
                West Lafayette, OH 43845

 
When:   August 24, 2005, 10am-1pm
 
Cost:    Free with lunch on your own
 

Winery contact information:

Phone: 740-545-1000

Fax: 740-545-9162

Website: http://www.ravensglenn.com

Email: vino@ravensglenn.com

*NO pre-registration necessary, but if you plan to come please contact Dr Imed Dami at Dami.1@osu.edu, Dave Scurlock at scurlock.2@osu.edu, or Todd Steiner at Steiner.4@osu.edu