Vineyard and Winery Information Series:
Vol. 15 No. 6, November-December 2000
Dr. Tony K. Wolf, Viticulture Extension Specialist
II.Viticulture Research Projects
In memory: Paul Steiner, Professor of Plant Pathology at University of Maryland, College Park, died at his home on Saturday, October 28th after a lengthy illness. Dr. Steiner was 58. Mid-Atlantic grape producers were familiar with Dr. Steiner through his tireless efforts at educating growers on grape disease management. A memorial to Dr. Steiner can be read at: http://www.marylandwine.com/mgga2/misc/ps_memorial_nn.html.
Commercial Grape Report for Virginia: The Virginia Agricultural Statistics Service is collecting their annual Virginia grape acreage and grape production data. Those with commercial vineyards should receive the survey questionnaire within the next 30 days. Please take a few minutes to complete and return the survey. State agencies such as Virginia Tech and Virginia Department of Agriculture and Consumer Services use the composite data to monitor industry growth, document program impacts, and justify fiscal and personnel resource expenditures. Your input is essential for accurate data! The 1999 Virginia grape production was 4560 tons, a 43% increase from 1998. New vineyards and increased production with existing vineyards may push that figure above 5000 tons this year. We are told that the Virginia grape data will make it into the federal crop report in 2001 or 2002. A review of the current, federal crop report ( http://www.usda.gov/nass/pubs/agstats.htm) suggests that Virginia currently ranks number six, nationally, in terms of grapes used in wine production.
Please contact the VA Agricultural Statistics Service (804-771-2493) if you grow one or more acres of grapes (bearing or non-bearing) and you do not receive a grape crop acreage-production survey questionnaire by 15 December 2000.
Potential vineyard sites for long-term lease: Frederick County, Virginia is the State's leading apple-producing county, with over 7,000 acres in orchard (if your geography's rusty, Frederick County is the northern-most county of the state; it's where Winchester is located). Ironically, it is a very minor player in terms of grape production; ironic in that there are prime vineyard sites in the county, an intact labor and infra-structure system to support grape production, and a close proximity to major metropolitan areas to draw wine consumers. With at least two working models of long-term vineyard lease arrangements now being used in the state, I asked Frederick County Cooperative Extension Agent Gary Deoms to informally discuss the concept of land-lease arrangements with potential orchardists. Tree-fruit producers have seen declining profits in recent years as apple prices remain static, and costs have increased. Dr. Deoms did indicate some positive feedback from area orchardists -- landowners who might be interested in 20- or 30-year lease arrangements with prospective grape producers who do not currently own land. We (Virginia Tech and Virginia Cooperative Extension) are not in a position to negotiate details of such arrangements, other than to help get potential lessors and lessees together to discuss the feasibility of long-term lease arrangements. Let me know (firstname.lastname@example.org) if this is something that you might be interested in. I would expect that the interested individual(s) would at least meet the following criteria:
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In the interest of keeping readers, producers and other stakeholders apprised of our research activities, the following briefly describes what we are currently doing with each of our major research projects. Each will be the topic of future in-depth presentations when data collection and interpretation are sufficient. I would like to acknowledge the fact that the Virginia Winegrowers Advisory Board has generously sponsored most of the research mentioned here.
Grape variety and clone evaluations:
Ten clones of Chardonnay were established at Winchester in 1998 for long-term evaluation. Clones include: #4, #5, #6, #15, #17, #25, #76, #95, #96, and #277. Data collection commenced in 2000 with measures of vine size, components of yield, and fruit chemistry. Small-lot winemaking will commence in 2001 or 2002 under Dr. Bruce Zoecklein's direction. Evaluations will continue for 6 to 8 years. We plan to expand into clone evaluations of Merlot, Cabernet franc, Petit Verdot, and Tannat within two years. In addition to the clone trials at Winchester, we have begun an evaluation of 20 wine grape varieties at our Southern Piedmont Agricultural Research and Extension Center in Blackstone, Virginia. The purpose of this planting is to evaluate the suitability of a range of varieties in Virginia's Eastern Piedmont. To date, our varietal recommendations for this area are based on limited grower experience, speculation, or just plain guesswork.
Significance: The Virginia wine industry is expanding; acreage increased from 1,565 in 1997 to 1,964 in 1999. Clientele are asking for detailed recommendations on suitable varieties and, more specifically, varietal clones. Data and interpretations from these studies addresses those questions. The vineyard at Blackstone will fill a void in our recommendations for varieties suitable for the Eastern Piedmont.
Defining appropriate crop levels for Chardonnay and Cabernet Sauvignon:
This research seeks to determine what the appropriate crop level is for balancing the somewhat competitive goals of maximizing crop (and wine) quality, sustaining high crop production, and optimizing wood and bud cold acclimation and mid-winter hardiness. Results to date have demonstrated that cane and bud cold hardiness can be reduced in the absence of visible delays in cane maturation, or periderm development by high crop levels. We were unable to repeat the highest crop (about 10 tons/acre) in Chardonnay since 1995 due to low fruitfulness (lower clusters/shoot and lower cluster weights). The Chardonnay work was repeated during the 2000 season with the additional factor of pruning type (spur-pruned vs. caned-pruned) being incorporated into the treatment design. Yield compensation has also occurred with the Cabernet vines: "high" crops in 1997 exceeded 10 tons/acre, but were only 6 tons/acre in 1998.
Significance: Aside from the impacts on wine quality, the results of this work are important for making accurate predictions about vine crop yields and how those yields can be expected to impact vine size (vigor) and cold hardiness.
Grapevine yellows is a destructive disease of grapevines. In Virginia, GY is mainly restricted to Chardonnay and Riesling, but other varieties have occasionally been affected. In Virginia, the disease is caused by one of two phytoplasmas, which are vectored by one or more unidentified leafhoppers. Research in 1999, which was continued in 2000, commenced a process of attempting to identify specific leafhoppers and alternative host flora that may be involved in the Virginia disease occurrence. This research is being done in collaboration with Dr. James Prince at California State University, Fresno. Weekly collection of leafhoppers from two vineyards in 1999, and subsequent PCR analysis of bulked samples (ca. 140 separate samples), revealed 7 samples, all from late in the summer, that were positive for phytoplasma DNA based on a universal PCR primer for phytoplasma DNA. We are currently having leafhoppers identified, and repeating the weekly surveys, which have been expanded to a third vineyard. Positive samples have again been identified from sampled collected in 2000; however, only about one-third of the 2000 season samples have thus far been analyzed. Artificial transmission studies were commenced with single-specimen leafhopper samples in August 2000 to gain information about the potential infectivity of positively identified leafhoppers.
Significance: Chardonnay represents more than 25% of grape acreage in Virginia. Some Chardonnay vineyards have, by attrition, lost more than 30% of their original plantings to GY. Identification of vector(s) and alternative hosts is a prerequisite to development of GY control strategies.
Training system comparison:
Vines are trained to different training systems due to varietal differences in growth habit, vigor or vine size differences, ease of vineyard mechanization, and growerıs opinion about potential effects on fruit/wine quality. Consequently, many types of grape training systems have been devised and are in use worldwide. No two systems have had formal evaluation in Virginia. Research commenced in 1998 to address that deficiency by way of multi-year field comparisons of two divided canopy systems (Geneva Double Curtain and Smart-Dyson) and a "standard", non-divided, vertically shoot-positioned system. An additional factor of variety (Traminette, Cabernet franc, and Viognier) was included in the treatment design. Fruit yield components and basic fruit chemistry data were collected for the 2000 season, and will continue for about 10 years. Additional data will be collected on ease of vine management (e.g., time required to train canopies), degree of bird depredation, rot, and other features. Collaboration with B. Zoecklein will allow examination of wine quality as well.
Significance: Basic trellis systems cost from $1,500 to $2,000 per acre, while more elaborate, divided canopy structures cost as much as $3,500 per acre. Virginia and other mid-Atlantic winegrape producers will benefit from this research through a better understanding of the costs, as well as the potential returns from several training system options.
Apogee® to restrict vegetative growth and reduce berry volume:
Apogee® (prohexadione-calcium) is a gibberellin biosynthesis inhibitor. Gibberellins are naturally occurring plant hormones. One function of gibberellins is the stimulation of vegetative and fruit growth. In Thompson Seedless and Flame Seedless grapes, for example, gibberellic acid is applied to increase berry size. In theory, if you reduce the vine's production of gibberellins, you might restrict growth. If excessive vegetative growth is an undesirable feature, a product like Apogee® might have a place in our vine management. Apogee®³ is registered for use on apples, so it conceivably might be registered for use on grapes if it was shown effective with its intended use. We informally evaluated Apogee®³ application to Cabernet Sauvignon in 1999 in an effort to restrict vegetative shoot growth. While we were largely ineffective in that goal, we did note a significant decrease in berry size. Experiments were expanded during the 2000 growing season, working with MS graduate student Danielle LoGiudice, to determine if rates and timing could be found that consistently and effectively reduced berry size of Cabernet Sauvignon, Cabernet franc and Seyval. In addition to berry size reductions, pre-bloom applications of Apogee® cause a significant reduction in fruit set, and ultimately yield. Refinements of rates and timing are planned for the 2001 season.
Significance: Reductions in berry size might contribute to greater wine quality due to greater concentrations of color and flavor constituents. Reductions in Seyval (or other rot-prone varieties) berry size might decrease susceptibility to botrytis bunch rot.
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A. Virginia Vineyards Association / Virginia State Horticultural Society Annual Meeting
22-24 January 2001
This meeting will be comparable to that held in Williamsburg in January 2000, and Roanoke in January 1999. Starting on Monday, 22 January, the "grape" portion of the meeting will run concurrently with the tree-fruits portion of the meeting through Tuesday, to be followed by a combined session with both audiences on Wednesday morning, 24 January. Program will include the following speakers and topics (program subject to slight change in speaker times):
Monday, 22 January
|Multiple topics related to wine marketing (details obtained at 804-371-7685)|
|1:00 pm:||Tony Wolf and Bruce Zoecklein, Virginia Tech|
|Review and discussion of 2000 growing season, with special attention to diseases, nutritional anomalies, fruit chemistry, and unusual observations|
|2:15 pm:||Speaker to be announced|
|3:00 pm:||David Ferree, Ohio State University|
|Rootstock trials and soil tiling (drainage) research in Ohio|
|4:00 pm||Richard Thomas, Santa Rosa Junior College|
|Current trends with new varieties, training/vine spacing, and vineyard technologies in Sonoma County, California|
|6:00 pm:||Reception (Registration fee includes cost of ticket, required for admission)|
Tuesday, 23 January
|8:00 am:||David Ferree, Ohio State University|
|Effects of shade (cloudy weather) on fruitfulness of Chambourcin|
|8:45 am:||Justin Morris, University of Arkansas|
|A systems approach to vineyard mechanization|
|10:15 am:||David Gadoury, Cornell University|
|Effects of low-level powdery mildew infestation on disease incidence and wine quality|
|11:00 am:||Jeff Derr and Tony Wolf, Virginia Tech|
|Weed competition and weed management options. Discussion to illustrate how weed competition affects vine growth/productivity, the fate of herbicides applied to vineyard soils, and what cultural and chemical weed control options exist.|
|11:30 am:||Doug Pfeiffer, Virginia Tech|
|Grape berry moth research and prognosis for the 2001 season|
|1:30 pm:||Andrew Landers, Cornell University|
|Vineyard commercial sprayer review, with update on research aimed at improving spray deposition and reducing drift|
|2:15 pm:||Bruce Zoecklein, Virginia Tech|
|Grape maturity assessment and sample analysis for growers. Discussion to include sampling procedures, maturity indices (e.g., Brix, pH, aroma/flavor, skin tannin maturity, etc), and basic sample analyses|
|3:00 pm:||Alice Wise, Cornell University|
|Chardonnay clone evaluations on Long Island. Ms. Wise has evaluated viticultural and enological qualities of over a dozen Chardonnay clones since they were planted in 1993 and 1994. Discussion will review major findings and will include a tasting of two or more clones.|
|4:00 pm:||Tony Wolf, Virginia Tech|
|Training system comparison of Shiraz in South Australia, and associated travelogue. A review of training system comparison (including minimal pruning and Scott-Henry) of Shiraz in the Barossa, followed by Shiraz wine tasting and travelogue of South Australia wine regions.|
Wednesday, 24 January (combined apple and grape grower audiences)
|7:30 am:||Buffet Breakfast (Registration fee includes cost of ticket, required for admission)|
|9:00 am:||Scott Eaton, James Madison University|
|Irrigation: availability of water resources|
|9:30 am:||John Crumpacker, Bowman Orchards|
|Orchard irrigation experiences|
|10:00 am:||Richard Thomas, Santa Rosa Junior College|
|Vineyard fertigation: materials and methods|
|11:00 am:||Steven Brown, Indian Springs Vineyard|
|Vineyard irrigation experiences|
|11:30 am:||Joe Davidson, Berry Hill Irrigation and John Nye, Mid-Atlantic Irrigation|
|Equipment considerations, costs, etc.|
|12:00 pm:||Mike Glenn, USDA/ARS, Kearneysville, WV|
|Summarization of the value of irrigation to fruit production in the Mid-Atlantic|
|12:30 pm:||Meeting adjourns|
In addition to the above, technical program, the meeting will feature an extensive trade show.
Registration: Register for this meeting by using the registration form. Note that registration fees increase substantially after 30 December.
Directions: Take I-64 to Williamsburg. Take the Williamsburg 242A exit. This will put you on Highway 199. Stay on 199 for about 2 miles. Take the Rt 60 East/West exit. When you come down the exit ramp turn left onto Rt 60 West. The Radisson Fort Magruder Hotel and Conference Center is approximately one mile on the left.
B. Pruning Workshops:
Date: Tuesday, 5 December 2000
When: 1:00 4:00 pm
Where: Silver Creek Orchards, Inc; Tyro, Virginia (Nelson County)
Details: Participants will review pruning and training principles and will observe pruning of young 'Chardonnay' and 'Cabernet franc' vines trained to bi-lateral cordons with VSP canopies. Participant hands-on pruning practice will follow. Bring pruners and dress accordingly.
Directions: From the north, take I-64 to Afton and then Rt 151 south. From the south, take Rt 29 to Rt 151, 2.0 miles north of Amherst. From Rt. 151, turn west onto Rt 56 towards Massies Mill, and go 3.7 miles. Turn left onto Rt 680 (Pharsalia Rd.) and go 1.2 miles. Turn right onto "Massie Lane" and go 0.1 (1/10) mile. Bear right and follow signs to vineyard at end of lane.
Date: Friday, 8 December 2000
When: 1:00 4:00 pm
Where: Virginia Tech's Agricultural Research and Extension Center, Winchester, VA
Details: Participants will review pruning and training principles and will observe pruning and training of young vines (3 years old) trained either to bi-lateral cordons with VSP training, Smart-Dyson, or Geneva Double Curtain (GDC). Participant hands-on pruning practice will follow. We will also have the opportunity to prune older 'Norton' trained to GDC, and 'Chardonnay' trained to lyre. Bring pruners and dress accordingly.
Directions: Virginia Techıs Agricultural Research and Extension Center (AREC) is located approximately 7 miles southwest of Winchester, VA in Frederick County. From Interstate-81, take the Stephens City exit on the south side of Winchester. Go west into Stephens City (200 yards off of I-81) and proceed straight through traffic light onto Rt 631. Continue west on Rt 631 approximately 3.5 miles. Turn right (north) onto Rt 628 at "T". Go 1.5 miles north on Rt 628 and turn left (west) onto Rt 629. Go 0.8 miles to AREC on left. We will meet in conference room.
C. Winegrowing seminars
Who: Jim Law, owner/winegrower Linden Vineyards
Where: Linden Vineyards
When: 10-11 February and 24-25 February 2000
Details: Course details and fee structure available by calling Linden Vineyards (540-364-1997), www.lindenvineyards.com Reservations required. Topics to include vineyard establishment, pest management, winemaking in the vineyard and winemaking basics. Not affiliated with Virginia Cooperative Extension.
"Viticulture Notes" is a bi-monthly newsletter issued by Dr. Tony K. Wolf, Viticulture Extension Specialist with Virginia Tech's Alson H. Smith, Agricultural Research and Extension Center in Winchester, Virginia. If you would like to receive "Viticulture Notes" as well as Dr. Bruce Zoecklein's "Vinter's Corner" by mail, contact Dr. Wolf at:
Dr. Tony K. Wolf
AHS Agricultural Research and Extension Center
595 Laurel Grove Road
Winchester, VA 22602
or e-mail: email@example.com
Commercial products are named in this publication for informational purposes only. Virginia Cooperative Extension, Virginia Tech, and Virginia State University do not endorse these products and do not intend discrimination against other products that also may be suitable.
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