Characterisation of viticultural and oenological practices in two French AOC in the middle Loire Valley: comparison of different methods to extract information from a survey among winegrowers

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The winegrowing sector consumes a lot of pesticides. Changes in vineyard are necessary in order to reduce or even stop using pesticides, and thus limit their harmful impacts on health and on environment. To answer these issues, the VITAE project (2021-2026) aims at designing pesticide free grapevine systems in France. For that, we take an interest in the vineyards using solutions to strongly reduce chemicals but also biopesticides. We assume that such vineyards exist and that they are implementing solutions that could inspire the design of free- pesticide system.

During wine conservation in a bottle, the control of oxygen transfer from the outside environment to the wine inside the bottle is a key parameter that determines the wine quality. Many other factors can also influence the evolution of wine during postbottling aging,

The notion of «terroir» refers to the link between the composition, quality and taste of a wine, on the one hand, and its place of origin, on the other. It involves, among other things, the signature of soil elements, as well as the influence of climatic conditions and plant material used. The composition of the wine is also influenced by the winemaking, storage and bottling processes. We were lucky enough to have a time series of the same champagne, from the end of the first world war to the present. On this exceptional time series, we followed, with the most advanced methods, all the elemental signatures by isotopic multi-dilution, the evolution of the isotopic ratios of heavy elements with very high precision of Sr, Pb, B and Cu.

Grapevine trunk diseases including Eutypa dieback are a major factor in the decline of vineyards and may lead to loss of productivity, reduced income, and premature reworking or replanting. Several studies have yielded results indicating that vines may be more likely to express symptoms of vascular disease if their health is already compromised by stress. In Australia and many other wine-growing regions it is a common practice for canes to be wrapped tightly around the cordon wire during the establishment of permanent cordon arms. It is likely that this practice may have a negative effect on health and longevity, as older cordons that have been trained in this manner often display signs of decay and dieback, with the wire often visibly embedded within the wood of the cordon. It is possible that adopting a training method which avoids constriction of the vasculature of the cordon may help to limit the onset of vascular disease symptom expression. A survey was conducted during the spring of two consecutive growing seasons on vineyards in South Australia displaying symptoms of Eutypa lata infection when symptomless shoots were 50–100 cm long. Vines were assessed as follows: (i) the proportion of cordon exhibiting dieback was rated using a 0–100% scale; (ii) the proportion of canopy exhibiting foliar symptoms of Eutypa dieback was rated using a 0–100% scale; (iii) the severity of strangulation was rated using a 0–4 point scale. Images were also taken of each vine for the purpose of measuring plant area index (PAI) using the VitiCanopy App. The goal of the survey was to determine if and to what extent any correlation exists between severity of strangulation and cordon dieback, in addition to Eutypa dieback foliar symptom expression.