Since 2006, an increasing number of French vineyards have chosen to convert to organic farming. One major change in vineyard practices includes replacing chemical pesticides with copper and sulfur-based products in line with Council Regulation (EC) No. 834/2007. This change can make overall management and pest and disease control more difficult and potentially lead to yield losses. From 2013 to 2016, a network of 48 vineyard plots, in southern France, under conventional management and in conversion to organic farming were monitored throughout the three-year conversion phase to investigate the grapevine phytosanitary management of four major pests and diseases and variations in control efficiency. The severity of downy and powdery mildew, grape berry moths, and Botrytis bunch rot were assessed and linked to the protection strategy. The findings showed that pests and diseases were controlled in the third year of conversion at similar efficiency levels as in conventional farming. However, the first two years of conversion were a transitional and less successful period during which higher incidences of cryptogamic diseases were observed. This demonstrates a need for winegrowers to receive more in-depth technical advice and support, especially on pest and disease control, during this critical transition period.

Given the need to reduce pesticide use and rising consumer demand for healthy food, organic vineyard areas have increased since 2000. Converting to organic farming requires numerous changes in pest and disease management, fertilization and weeding techniques. These changes can lead to difficulties in sustaining yields. Some studies have highlighted higher yields in conventional farming than in organic agriculture, but knowledge on yield dynamics during conversion is lacking. A set of 26 plots, under conventional management and in conversion to organic farming, were monitored from 2013 to 2016 in southern France throughout the three-year conversion phase to investigate the dynamics of grape yield and yield components. The survey showed that the yield and yield components remained similar levels as in conventional farming from the third year of conversion. However, the first two years of conversion were a transitional and less successful period during which yield and yield components decreased. Based on the in-depth analysis of the yield components, we have put forwards hypotheses on the processes at play and technical advice that could support winegrowers as they convert to organic farming.

Vineyard decline is one of the main challenges viticulture now faces, especially in the current context of climate change. While decline is often attributed to grapevine trunk diseases and climate change, it also involves a myriad of other interconnected factors, including agricultural practices, whose role in decline remains unclear. This study explored for the first time how various planting conditions and agricultural practices implemented over an extended period of time affect the intensity and dynamics of decline. We analysed a large dataset obtained from 107 plots in the Cognac wine-growing region in western France from 1988 to 2018. The dataset included data on soil and climate conditions, genetic material at planting, annual agricultural practices, and information on annual mortality and yield. This study comprised six steps: dataset building, characterisation of decline categories, selection of explanatory variables to be studied, creation of plot trajectories based on agricultural practices, linking of decline categories and plot trajectories, and analysis of plot characteristics and practices. Using data from 43 plots and 58 variables, we showed that vineyard plots can be classified into three stages of decline depending on the dynamics and intensity of mortality and yield dynamics. We then established 11 trajectories over the plot lifespans (16 to 30 years). A detailed analysis of these trajectories revealed that plots associated with certain trajectories were more subject to decline, which helped us identify strategies that could limit or even prevent decline. We concluded that preventing decline requires adopting an integrated approach from planting to grubbing up, finding the right match between genetic material and soil–climate conditions, ensuring optimal water management, and managing potentially competing vegetation, like cover cropping. By identifying key practices over the vineyard lifespan, this study opens up new avenues for preventing decline by putting the focus on vigour management, water and mineral status of the plant.

Since the beginning of the 20th century, the official French agricultural warning service (Ministry of Agriculture) has published weekly reports and annual summaries of key pest and disease pressures. The summaries were based on a large number of plots, including untreated ones, located in many different regions, with different local editions in every region. They constitute a highly valuable body of literature on pest and disease presence and overall damage, notably in vineyards. We used this literature to develop a textual analysis and build an integrative grading system for assessing a posteriori annual pest occurrence and damage intensity over an extended period (1941 to 2023) in the Bordeaux, Champagne and Vaucluse wine-growing regions. To reconstruct the pest and disease occurrence and intensity over time in the three regions, we established a long-term database of annual grades. The various grapevine diseases include notably downy and powdery mildews, black rot, rotbrenner and gray mold and, for the phytophagous insects, European vine moth (Lobesia botrana) and vine moth (Eupoecilia ambiguella). This tool can be very useful for characterizing the epidemiological status of various years or vintages, and analyzing long-term trends versus more isolated events. This will allow us to better describe and understand historical pest and pathogen temporal dynamics and link them to biotic and/or abiotic contexts. This will be helpful for anticipating needed advances in grapevine protection against quantitative and/or qualitative loss and for adapting viticulture to global changes including climatic, regulatory and marketing dynamics.