- Fruits: grapes
- Farm Business Management: budgets/cost and returns
- Production Systems: general crop production
Improving economically and environmentally sustainable vineyard practices to produce high-quality wine grapes is a top priority for the advancement of the Northeast wine industry. Cluster thinning (CT) is a common crop regulation practice used by growers to improve fruit and wine quality of high-yielding wine grape varieties; however CT requires skilled labor and is time consuming. The additional costs associated with implementing this practice may discourage some growers from applying it. Moreover, failure to reduce crop levels for highyielding grape varieties may lead to over-cropping, potentially increasing susceptibility to winter injury, which is a major limitation of wine grape production in the Northeast. Removing leaves from the grapevine fruit-zone from bloom to fruit-set (early leaf removal, ELR), may provide an alternative method for reducing crop levels. Additionally, ELR provides benefits such as decreasing fungicide inputs for Botrytis rot control and easier mechanization compared to CT for cost reduction. Our project proposes to conduct a field trial on impacts of ELR and CT on yield components, fruit quality, and Botrytis rot severity compared to un-thinned, non-defoliated vines. This study will be performed on V. vinifera Grüner Veltliner, an economically important variety for coolclimate regions. An economic analysis will be performed to determine the suitability of ELR as a cost-effective alternative to CT. Impacts of crop regulation practices on vine cold hardiness and over-winter carbohydrate storage will be measured, providing critical information to growers on the impact of those practices on vine health and susceptibility to winter cold temperature injury.
Project objectives from proposal:
1. To conduct a field trial to assess and compare the effects of cluster thinning (CT) and early leaf removal (ELR) on vegetative growth, yield components, Botrytis bunch rot infections, cluster compactness, bud fruitfulness, and fruit composition.
2. To assess the impact of CT and ELR on parameters associated with vine susceptibility to winter injury, including single-leaf net carbon assimilation, bud and cane cold hardiness, and carbohydrate reserve storage.
3. To perform an economic analysis that estimates the additional price per tonne of fruit and cost per 750 mL bottle of wine needed to maintain grower economic welfare, if CT and ELR practices were adopted compared to if they were not.
4. To provide recommendations to stakeholders for managing high-yielding wine grape varieties for optimal fruit composition and vine health.