Oenological tannins to prevent Botrytis cinerea damage: reduction of laccase activity

The AOC Saint-Emilion, one of the most prestigious in Bordeaux, is located on the right bank of the Dordogne upstream from Libourne. The vineyard is planted on Tertiary (Oligocene) and Quaternary geological formations, on which very varied soils have developed. Numerous studies have taken account of this heterogeneity and made it possible to better understand the functioning and viticultural potential of these soils (Duteau et al. 1981, Van Leeuwen, 1991).

Context and purpose of the study ‐ Recently early defoliation (ED) has been tested in several high‐ yielding grapevine varieties and sites aiming at reducing cluster compactness and hence, regulating yield and susceptibility to botrytis bunch rot infection. The reported results have been generally positive, encouraging growers to use this canopy management technique as an alternative for replacing the conventional time‐consuming cluster thinning and, simultaneously, as a sustainable practice to reduce the use of fungicides. However, ED increases berry sunburn risks and/or can induce carry‐over effects on vigor and node fruitfulness as shown in the two case studies reported in this work.

Viticulture is facing two major challenges – climate change and agroecological transition. The soil plays a pivotal role in these transition processes. Therefore, soil quality and adequate soil management are key levers for an ecologically and economically sustainable viticulture. Over the last 15 years, numerous studies evidenced strong effects of viticultural practices on the soil physical, chemical and biological quality. However, to date a global analysis providing a comprehensive overview of the ecological impacts of viticultural practices on soil biological quality is missing.

The Columbia Valley American Viticultural Area (AVA) of the Pacific Northwest, USA is the world’s largest officially recognized viticultural area with basalt bedrock.

Wine grapes breeding has been concentrating a lot of efforts within the grape research community over the last decade. The quick phenotyping of genotype quality traits including aroma composition remains challenging. Selected Ion Flow Tube Mass Spectrometry (SIFT-MS), a technology first available in 2008 and developing rapidly, could be particularly valuable for this usage. The aims of this study were i) to use SIFT-MS, to analyze the whole volatilome from different grape varieties, ii) to assess the ability of this technology to discriminate varieties according to their grape aroma composition, and iii) to study the stability of SIFT-MS signal over maturation to define a sampling strategy.