Utilizing ozone for the management of powdery mildew (Erysiphe necator Schwein.) in vineyards: potential and challenges

The Cognac region is expanding, driven by the success of its renowned brandy and the demand for high grape yields to ensure a steady supply of base wine for distillation. Ugni blanc, the most widely planted grape variety, relies on rootstocks for soil and climate adaptation, providing essential nutrient supplies to the scion. Understanding the impact of rootstocks on key berry components, such as sugars and nitrogen compounds, is crucial. These compounds serve as primary precursors for the production of fermentative aroma metabolites, which, in turn, act as quality indicators for eau-de-vie.

More frequent and extreme temperatures and droughts pose challenges to the wine sector in Mediterranean Europe. Soil is crucial to sustain the equilibrium of ecosystems, economic growth and people’s prosperity worldwide. In viticulture, soils are a major component of the terroir and do influence vine’s growth, yield and berry composition. Soil temperature (ST) affects soil´s physical, chemical and biological processes and also crop growth. The impact of ST becomes even stronger when dealing with row crops such as grapevine, when considering the increased exposition to radiation. However, the impact of ST on crop performance remains poorly described, especially for extreme climatic conditions.

The use of selected cultures of the species Lactiplantibacillus plantarum in Oenology has grown in prominence in recent years. While initial applications of this species centred very much around malolactic fermentation (MLF), there is strong evidence to show that certain strains can be harnessed for their bio-protective effects. Unwanted spontaneous MLF during alcoholic fermentation (AF), driven by rogue Oenococcus oeni, is a winemaking deviation that is very difficult to manage when it occurs. This work set out to determine the efficacy of one particular strain of Lactiplantibacillus plantarum(Viniflora® NoVA™ Protect), against this problem in Cabernet Sauvignon must. The work was carried out at commercial scale and in a winery environment and compared the bio-protective culture with the more traditional approach of reducing must pH by the addition of tartaric acid. The combination of both was also investigated. The concentration of both Oenococcus oeni and Lactiplantibacillus plantarum was determined using qPCR. The adventitious Oenococcus oeni showed the most growth during AF in the control wine, whereas in the wines treated with Lactiplantibacillus plantarum a bacteriostatic effect against this species was observed. This effect was comparable to the wines treated with tartaric acid. This has particular commercial relevance for controlling the flora in musts with high pH, or when the addition of tartaric acid is either not permitted or is prohibitive for other reasons.

The behaviour of cv. “Tinta Roriz” (Vitis vinifera L.), was studied when moderate drip irrigation was applied from veraison to harvest. Field studies were conducted during three growing seasons

French law and European Union law recognise the existence of interprofessional organisations that bring together all the links in the wine industry.