L’étude “terroirs d’Anjou”: un exemple de caractérisation intégrée des terroirs viticoles, utilisable à l’échelle parcellaire

In this audio recording of the IVES science meeting 2022, Gonzaga Santesteban (Department of Agronomy, Biotechnology and Food Science, Public University of Navarra (UPNA), Pamplona, Navarra, Spain) speaks about cover crops in viticulture. This presentation is based on 2 original articles accessible for free on OENO One.

The reflections presented here are a synthesis of a set of research on the construction of a scientific logic concerning the relations between the terroir, the vine, the wine, and on the study of a product, the wine, considered as the resulting from many interactions between factors of various orders. This work has benefited greatly from discussions of an epistemological as well as a technical nature with all the researchers at URVV (Angers) and with our colleagues at the Institut National des Appellations d’Origine, over several years.

The spotted lanternfly (SLF; Lycorma delicatula) is a phloem-feeding polyphagous insect invasive to the Eastern U.S.. Since its first detection in Pennsylvania (U.S.) in 2014, large infestations and economic damage (e.g., decreased yield, vine decline, greater pesticide use) have been reported in an increasing number of vineyards, threatening the sustainability and growth of the wine industry in infested regions. Our team has been investigating the impacts of SLF phloem-feeding on physiological processes, fruit production, juice, and wine composition of different grape cultivars, and also evaluated if the SLF can transmit important grapevine pathogens. In addition, we are working closely with stakeholders to better enumerate the economic damage caused by this pest. These findings will provide relevant information to grape and wine producers to help identify action thresholds and develop a more targeted integrated pest management program.

Oenococcus oeni is the main Lactic Acid Bacteria responsible for malolactic fermentation, converting malic acid into lactic acid and carbon dioxide in wines. Following the alcoholic fermentation, this second fermentation ensures a deacidification and remains essential for the release of aromatic notes and the improvement of microbial stability in many wines. Nevertheless, wine is a harsh environment for microbial growth, especially because of its low pH (between 2.9 and 3.6 depending on the type of wine) and nutrient deficiency. In order to maintain homeostasis and ensure viability, O. oeni possesses different cellular mechanisms including organic acid metabolisms which represent also the major pathway to synthetize energy in wine.

Wine color is one of the main organoleptic characteristics influencing its quality. It is of especial interest in red vinifications due to the economic resources that wineries have to invest for the extraction of the phenolic compounds responsible of wine color, compounds that are mainly located inside the skin cell vacuoles. Moreover, these phenolic compounds not only influence color but also other organoleptic properties such as body, mouthfeel, astringency and flavour. The transference of phenolic compounds from grapes to must during vinification is closely related with the type of grapes and the winemaking technique.