Speakers
Description
Context and purpose of the study - The winegrowing sector consumes large amounts 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 address these issues, the VITAE project (2021-2026) aims at assessing and designing pesticide free viticulture in France. For that, we searched for commercial vineyards that have already adopted strategies strongly reducing chemical pesticide but also biopesticides. We assume that such vineyards are implementing solutions that could inspire the design of pesticide-free systems. Thus, the objective of this study was to characterize the solutions implemented in these commercial plots that allow winegrowers reduce pesticides and then to assess associated performances.
Material and methods – A network grouped 14 commercial plots among the six main French wine-regions. Plots were selected on their environmental performance only (60% pesticide reduction compared to regional reference), not on their localization or production modes so that they covered a wide diversity of production contexts (biotic, abiotic and socio-economic contexts). The three-year observations consist in the characterization of all the compartments of the agrosystem that influences the systemic pest and disease management: vine, cultivated associated vegetation in the plots -mainly in the inter-row and under the row, natural associated vegetation in the plot and in the surroundings, pests and diseases, soil (figure 1). We also monitored vineyard performances in quantity (yield) and in quality (grape quality) and collected information on practices during one growing season of vine (2023). All the commercial plots are positioned along a gradient of pesticide use intensity and the corresponding farm is characterized by its position along an agroecological gradient.
Figure 1: Systemic approach of low input vineyard and list of observations performed in boxes.
Results – The results from the 2023 vintage showed an important diversity among the plots on most of the indicators monitored. In 2023, vineyards faced high downy mildew pressure with important yield loss reported in half of the wine-growing regions. This particular context affected the strategy of disease control in the network. The agronomic performance was reached for 9/14 plots when compared to grower’s objective. Important yields loss was reported in 4 plots (more than 50%). In 8/14 plots, the pesticide use was lower than the regional average and the yield acceptable. In these plots, the severities and incidences for downy and powdery mildew were limited and acceptable according to the winegrowers’ objectives. We observed an important heterogeneity in the yield components and vegetative development within each plot. The vines did not suffer from lack of nitrogen in the majority of the plots followed but we showed a water stress, notably under Mediterranean climate in absence of irrigation. Eleven over the 14 plots presented a voluminous vegetation in the inter-row Soil structure, represented by aggregate stability, complied with standard.
Perspectives – 2023 constituted the first year of monitoring. Two additional years of measurement are planned to cover a diversity of weather and biotic pressure conditions. Understanding these very low pesticide commercial plots require a pluri-annual assessment. At the same time, soil microbiological quality, oenological quality and biodiversity indicators will also be measured and will be used in a multicriteria assessment of these innovative systems toward stopping pesticide use. Year 2023 showed that some of the cropping systems followed were promising systems to inspire changes in other vineyards.
| Keywords | Grapevine; innovation; pesticide reduction; agroecology; plot network; systemic approach |
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