Influence of pre-fermentative steps on varietal thiol precursors

Elemental sulfur is a fungicide used by grape growers to control the development of powdery mildew, caused by the fungus Erysiphe necator. This compound is effective, cheap and has a low toxicity with no withholding period recommended. However, high levels of S0 residues in the harvested grapes can lead to the formation of reductive sulfur compounds that can impart taints and faults to the wine. Hydrogen sulphide (H2S) is a very volatile and unpleasant sulfur compound which formation is connected to high residues of S0 in juice (10 – 100 mg/L).

Aims: The aims of this study are to determine the influences of the local geology, mineralogy and geochemistry of surroundings, substrate and soil on the cultivation of vines, these as an additional factor of specificity and locality in the production of wine and definition of terroir, as well as for the discrimination of local variance of substrate and soil properties for the strategic management of cultivation plots and/or the evaluation of new cultivation regions, necessary within a scope of global climate change.

A gradual decline in vineyards has been observed over the past twenty years worldwide. This might be explained by the climate change, practices change or the increase of dieback diseases. To increase the longevity of vines, we studied the impact of different pruning strategies in four adult and four young vineyards located in France and Spain. In France, vineyards were planted with Cabernet franc on 3309C while Spanish trials were planted with Tempranillo grafted on 110R. Vegetative expression, yield, quality of berries and wood vessels conductivity were measured. The distribution of vegetative expression, yield and berry composition between primary and secondary vegetation were quantified. Finally, tomography was used to evaluate the implication of the treatments on sap flows.
First results show that i) the respectful pruning leads to an increase of 30 to 50% more secondary shoots than the aggressive pruning in France and between 15 and 20% in Spain, ii) there is no major effect on the yield over the first two years following the implementation of the new pruning practices, although the proportion of clusters from suckers is higher on the respectful pruning method. On young vines, the development of the trunk according to a respectful pruning leads to a loss of harvest 2 years after planting. This is due to the removal, on the future trunk, of the green suckers which carrying bunches. This operation carried out in spring rather than during winter pruning, would promote a better leaf / fruit balance when the plant comes into production, and could lead to better hydraulic conduction in the vessels of the trunk. Maintaining these trials for several years will provide more robust data to assess the impact of these practices on the vines over the long term.

Il mal dell’esca é una malattia della vite della quale sono state studiate sintomatologia, eziologia, patogenesi ed epidemiologia. Essendo una malattia che colpisce soprattutto la parte epigea delle piante, le caratteristiche dei suoli non sono mai state considerate fra le responsabili della sua insorgenza e diffusione.

Viticulture has spread to unexpected locations, such as high-altitude terrain. Among these, high-altitude viticulture has captured considerable attention, not only for the uniqueness of its products and landscapes but also because it offers an effective response to climate changes
The aim of this study is to analyse and compare wineries that used Piwi varieties (acronym for the German Pilzwiderstandfähig, i.e., cryptogame-resistant) at high altitudes (between 500 and 920 m a.s.l.) with the traditional non-mountainous viticulture model.