We are preparing to start this project on April 1, 2018 as highlighted in the proposal with the SARE funds and will be pruning vines prior to April 1.
The purpose of this project is to further investigate the use of palissage to reduce disease incidence and fungicide use in winegrapes.
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 cinerea 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 cinerea (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).
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 partial budget 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.
Methods and timeline
(Methods and timelines are as described in the proposal)
The study was established in growing season 2016 and will continue to be conducted 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)) will be 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, will be quantified as detailed in the proposal. Canopy structure (i.e., leaf and cluster light interception) will be 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 at bunch closure, and veraison, when vines are most susceptible to Botrytis cinerea, spray penetration to clusters will be evaluated with spray penetration cards as described in the proposal (Salyani et al 2013).
At harvest, laterals will be counted and grapes from each experimental unit will be harvested according to the proposal for yield per vine. After yield data collection, twenty clusters from each experimental unit will be quantified for Botrytis cinerea bunch rot severity and incidence and cluster compaction as detailed in the proposal (France 2017). An additional twenty clusters per experimental unit will be collected and analyzed for pH, Brix, titratable acidity, and yeast assimilable nitrogen, using standard procedures (France 2017).
In the winter, 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).
As detailed in the proposal, the time spent applying all treatments will be evaluated and recorded on several vineyard blocks at Lansing and LIHREC in collaboration with Alice Wise and the Cornell Orchards staff. Using the time required for all treatment applications, a partial budget including published costs for hedging, leaf removal, and fungicide application, will be developed with Todd Schmit, a collaborator in the Dyson School of Economics (Yeh et al 2014).
Cane prune and shoot thin to a standard shoot count
Identify and measure 4 shoots per vine or 32 shoots from each experimental unit for all treatments throughout the season for growth rates.
Collect and analyze Spray penetration data with spray cards will be collected and analyzed
following sprays at bloom, fruit set, and veraison.
Time and Apply Timing 1 treatments at 30 centimeters in height from the fruiting wire
Time and Apply Timing 2 treatments at 90 centimeters
Quantify canopy structure at veraison with EPQA
Count laterals at veraison or post-harvest
Sample grapes for harvest timing
At harvest, obtain yields per vine and sample clusters for cluster compactness and Botrytis cinerea quantification
Statistical analysis and presentation of data and results from 2018 growing season at the Cornell Recent Advances in Viticulture and Enology conference.
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 2019.
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.
Education & Outreach Activities and Participation Summary
As the start date of the project will be on April 1, 2018, data from this project will be analyzed and summarized then shared with the scientific and industry communities in 2018 and beyond through publications, meetings with growers, and conferences.
N/A – project start date is April 1, 2018
N/A – project start date is April 1, 2018
N/A – project start date is April 1, 2018