Exploring zoxamide sensitivity in Plasmopara viticola populations: implications for fungicide management in precision agriculture

Promoting sustainable agricultural practices is one of the challenges of the last decades. Organic and biodynamic viticulture can be an alternative to intensive viticulture, furthermore contributing to reduction of impact on environment and human health and guaranteeing soil preservation and quality products1. The aim of this experimentation was to evaluate the medium and long-term effects of different agronomic practices in viticulture on nutrient availability and heavy metal accumulation in soil.

Le terroir peut être défini comme un écosystème dans lequel la vigne interagit avec le climat et le sol et dont la résultante est le vin.

Global change in climate affect regional climates and hold implications for viticulture worldwide. Despite numerous studies on the impact of projected global warming on different regions

In wine grape production, canopy management practices are applied to control the source-sink balance and improve the cluster microclimate to enhance berry composition. The aim of this study was to identify the optimal ranges of berry solar radiation exposure (exposure) for upregulation of flavonoid biosynthesis and thresholds for their degradation, to evaluate how canopy management practices such as leaf removal, shoot thinning, and a combination of both affect the grapevine (Vitis vinifera L. cv. Cabernet Sauvignon) yield components, berry composition, and flavonoid profile under context of climate change. First experiment assessed changes in the grape flavonoid content driven by four degrees of exposure. In the second experiment, individual grape berries subjected to different exposures were collected from two cultivars (Cabernet Sauvignon and Petit Verdot). The third experiment consisted of an experiment with three canopy management treatments (i) LR (removal of 5 to 6 basal leaves), (ii) ST (thinned to 24 shoots per vine), and (iii) LRST (a combination of LR and ST) and an untreated control (UNT). Berry composition, flavonoid content and profiles, and 3-isobutyl 2-methoxypyrazine were monitored during berry ripening. Although increasing canopy porosity through canopy management practices can be helpful for other purposes, this may not be the case of flavonoid compounds when a certain proportion of kaempferol was achieved. Our results revealed different sensitivities to degradation within the flavonoid groups, flavonols being the only monitored group that was upregulated by solar radiation. Within different canopy management practices, the main effects were due to the ST. Under environmental conditions given in this trial, ST and LRST hastened fruit maturity; however, a clear improvement of the flavonoid compounds (i.e., greater anthocyanin) was not observed at harvest. Methoxypyrazine berry content decreased with canopy management practices studied. Although some berry traits were improved (i.e. 2.5° Brix increase in berry total soluble solids) due to canopy management practices (ST), this resulted in a four-fold increase in labor operations cost, two-fold decrease in yield with a 10-fold increase in anthocyanin production cost per hectare that should be assessed together as the climate continues to get hot.

The tartaric stabilization of wines before bottling to avoid the precipitation of tartaric acid salts is an important and common step during wine production. The presence of precipitated salt crystals in bottle wines is detrimental for their quality and even a legal issue in some countries. Cold stabilization is the most common stabilization treatment. Although it has been shown to be effective, it has some significant disadvantages, mainly regarding losses of color and aromas and its high cost. Therefore, other products and methodologies are being introduced in the wineries for the replacement of this process. Some of these new techniques involve the reduction of the ions causing the insolubilization of tartaric acid while other are based in the formation of protective colloids or the inhibition of the crystallization of salts. In this study, white, rosé and red wines have been treated with carboxymethylcellulose, potassium polyaspartate and an ion exchange resin. The tartaric stability of the wines, together with the oenological, chromatic and sensory characteristics were studied after the wines had been stored during one year in the bottle. The results indicate that the use of carboxymethyl cellulose and potassium polyaspartate maintained the best the sensory and chromatic characteristics and the wine stability of the wines in comparison with an untreated control wine.