Palissage is a promising alternative to hedging that has only recently been studied. However, the timing of palissage technique application has not been studied so a study was initiated to evaluate using palissage techniques at two timings (Timing 1 = 30 cm and Timing 2 = 90 cm above the top catch wire) and effects on canopy density parameters, lateral emergence in the fruit zone, fruit composition, spray penetration to the clusters, and crop yields.
Palissage techniques decreased lateral emergence in the fruit zone by 27% between the hedged Control and Shoot wrap, regardless of timing. Cluster compaction, or the number of berries per cm, also was reduced by technique only, with Shoot Wrap having the lowest cluster compaction at a little more than 6 berries per cm of rachis, potentially reducing cluster rot. Yields were highest for Shoot Tuck overall, with more than 1 kg of crop per vine more than Control, and all treatments at Timing 2 had higher yields than Timing 1. There seems to be no difference in fruit composition except for yeast assimilable nitrogen, which is about 20% higher in Shoot Tuck, regardless of timing, than in the hedged control. Spray penetration to the clusters increased by 60% between Control at Timing 1 and Shoot tuck at Timing 2; Shoot Wrap at Timing 2 had similar levels of spray penetration with Shoot Wrap at Timing 2 as a close second. Palissage has the potential to be used by growers in place of hedging as it may improve economic sustainability of vineyard management.
1. To determine whether the timing (early vs. late) and method (shoot tucking vs. shoot wrapping) of palissage compared to hedging will reduce vegetative growth (lateral emergence) and vigor, reduce cluster shading, reduce disease incidence and cluster compactness, and improve fungicide penetration in Cabernet Franc winegrapes.
2. To evaluate carry-over effects of palissage on the same site established in the cool and wet Northeast through 2019 as a sustainable alternative to hedging.
3. Develop a cost analysis to determine the economic impact of palissage compared to hedging.
4. Educate the New York State winegrape industry about the potential of palissage through Appellation Cornell newsletters, tailgate talks with growers, and grower conferences.
Growing Vitis vinifera winegrapes (i.e. commonly-grown European cultivars such as Riesling and Cabernet Franc) in the Northeast US comes with many challenges including the cultivars’ susceptibility to fungal diseases including Botrytis cinereal and excessive vine vigor due to the region’s cool and wet climate and high organic matter soils. Excessive vine vigor (long internodes, strong lateral growth, and large leaves) leads to longer periods of leaf and fruit wetness and limited light penetration in the fruiting zone, lower spray penetration, and a humid microclimate, all of which lead to more and longer disease infection periods.
Current canopy management practices exacerbate the consequences of excessive vigor (Wolf 2008). To limit excessive vegetative growth, winegrape growers hedge their canopies by cutting off shoot tips intermittently throughout the growing season in vertically shoot positioned training systems (Wolf 2008). While the canopy density is temporarily reduced through hedging, hedging ultimately promotes lateral emergence and extension in the fruiting zone especially when applied early (Reynolds et al 1989; Molitor et al 2015; France 2017). These emerging lateral shoots increase the duration of cluster wetness following periods of rain, shade the fruit, and reduce spray penetration to the clusters. Hedging also enhances the transfer of assimilates to the developing inflorescences, which is often linked to compact clusters (Molitor et al 2015). Compact clusters are highly correlated with Botrytis cinereal (Vasconcelos et al 2000).
A novel alternative approach to hedging, “palissage” is being evaluated by the Vanden Heuvel research group at Cornell. When palissage is applied, shoots are either wrapped around the top catch wire, or tucked back down into the canopy (Figure 1). After reports from many growers about the benefits of palissage through grower surveys, two small trials were initiated to investigate the practice. The results have been very promising thus far; lateral emergence and cluster compaction were reduced in these trials. Earlier cessation of shoot growth and reduced lateral emergence were also reported by growers, eliminating the need for leaf removal to open up the canopy (Vanden Heuvel, unpublished data). Palissage has the potential to improve light interception to the clusters and wine quality. Given a significant reduction in disease incidence on palissaged vines in contrast to hedged vines, palissage can be incorporated in the grower’s disease management program, reducing the need for fungicides (France 2017).
The study was established in growing season 2016 on Vitis vinifera Cabernet Franc cl. 4 grafted on 3309c rootstocks located in a 0.25 ha research vineyard in Lansing, NY with two experimental units per row as described in the proposal. Three shoot tip management methods (shoot wrapping, shoot tucking, hedging (control)) were evaluated in a randomized complete block design in a factorial with two timings of treatment application: early (shoots reach 30 cm above the top wire) and late (shoots reach 90 cm above the top wire).
Shoot length and diameter of both primary and lateral shoots of 32 shoots per experimental unit in the fruiting zone for all treatments, were quantified as detailed in the proposal in 2018. Canopy structure (i.e., leaf and cluster light interception) was analyzed on each vine using enhanced point quadrat analysis at pre-harvest as described in the proposal (Meyers and Vanden Heuvel 2008).
Following spray application of water at veraison, when vines were most susceptible to cluster rot, spray penetration to clusters was evaluated with spray penetration cards, by counting the number of grids that had more than 50% coverage, with blue color indicating spray coverage and yellow color indicating no spray coverage (Salyani et al 2013).
At harvest, lateral shoots in the fruit zone were counted and measured in the fruit zone, mid canopy, and upper canopy and grapes from each experimental unit were harvested according to the proposal for yield per vine on October 15, 2018. Twenty clusters per experimental unit were collected and analyzed for pH, Brix, titratable acidity, and yeast assimilable nitrogen, using standard procedures (France 2017).
In March 2019, when cane-pruning dormant vines to 40 nodes, weights of fruiting wood from the previous growing season will be collected for each vine in each experimental unit for all treatments as discussed in the proposal (France 2017).
Treatments: Control, Shoot Tuck, and Shoot Wrap were photographed below:
Cane pruned and shoot thinned to a standard shoot count of 40 shoots per vine
Identified and measured 4 shoots per vine or 32 shoots from each experimental unit for all treatments throughout the season for growth rates.
Collected and analyzed Spray penetration data with spray cards
following water spray at veraison.
Applied 1 treatments at 30 centimeters in height from the fruiting wire
Applied Timing 2 treatments at 90 centimeters
Quantified canopy structure at veraison with EPQA
Counted laterals at veraison
Presented at American Society of Enology & Viticulture – Eastern Section Conference
Harvested grapes to obtain yields per vine and sample clusters for cluster compactness
Winter 2018-Early Spring 2019:
Cane pruning of vines to 40 nodes per vine and pruning weight collection to calculate the vegetative to reproductive growth ratio.
Spring and Summer 2019:
Reestablish treatments and repeat data collection as in 2018
Tailgate discussions with growers about palissage results from 2018.
Fall and Winter 2019
Statistical analysis and presentation of data and results from previous and current growing seasons for presentation at the Business, Enology, and Viticulture conference in March of 2020.
Summarize data and results from all growing seasons evaluated to be shared in Cornell newsletters and presented at several conferences including the American Society for Viticulture and Enology –Eastern section conference.
Submit manuscript to the American Society of Enology and Viticulture journal for publication.
RD_SARE2018 – see attachment
Education & Outreach Activities and Participation Summary
This project is being analyzed and summarized. Parts of the findings were shared at the American Society of Enology and Viticulture – Eastern Section conference in 2018. The project will continue to be shared with the scientific and industry communities through publications, meetings with growers, and conferences.
Lateral emergence was reduced by 27% by shoot wrap, regardless of timing in the fruit zone, both in length and in number per vine, potential improving cluster microclimate and reducing cluster rot disease incidence and severity. Cluster compaction, or number of berries per cm, was also reduced by technique only, potentially reducing cluster rot. Spray penetration, using water, to the fruit zone is improved with both palissage techniques, at Timing 2. Shoot Tuck exacerbated Downy Mildew incidence and both Shoot Wrap and Shoot Tuck had slightly higher Downy mildew severity than Control at the earlier timing. This year was a very wet year, compared to previous years, which may have worsened downy mildew incidence and severity.
However, some canopy metrics were slightly improved with palissage techniques with slightly higher leaf and cluster exposure flux availability in Shoot Wrap, potentially increasing light penetration and aeration to the clusters and leaves. There were also reductions in percent interior leaves in Shoot Wrap, possibly meaning higher photosynthesizing and potentially increasing reserves for the fruit and roots to improve the vine’s cold hardiness and percent budbreak. Yields were higher by 1 kg in the Shoot Tuck technique but did not differ greatly between Shoot Wrap and Control
Palissage has the potential to be used by growers in place of hedging as it did not require more than one trip through the vineyard due to successful reductions in lateral emergence and cluster compaction, improving spray penetration, and thus, requiring less fungicide spray and increasing the sustainability of vineyard management.
Pruning weights from 2018 will be collected in March or April of 2019 during pruning to quantify the ratio of vegetative growth by ways of pruning weights to yield (crop load) and observe if palissage techniques and/or timing will improve the ratio. This project will be also evaluated for one more growing season. It would make sense to repeat timing trials on tight clustered cultivars such as Riesling and Pinot Noir to observe impact of timing of palissage application on Botrytis cinereaand other cluster rots as that was something not observed in the Cabernet Franc vines used for this study. Mechanisms behind the reductions in lateral emergence, cluster compaction, and increases in yeast assimilable nitrogen, an important element for vinification ought to be explored in depth to better understand how to improve palissage as a promising tool for growers.