Diversity of pesticide use trajectories during agroecological transitions in vineyards: The case of the French DEPHY network

CONTEXT: Winegrowers apply large quantities of pesticides to their vineyards to reduce high cryptogamic pressure. But these practices must change to lower pesticide use and improve viticulture sustainability. Different options for curbing pesticide use exist, and they can be progressively implemented following a specific temporal scheme in each production system. Some change trajectories can be more efficient than others in limiting pesticide applications. Combining trajectory studies and typology may be helpful in characterizing how farmers change their practices and in summarizing the various production system trajectories possible when transitioning towards pesticide use reduction. OBJECTIVE: The aims of this study were i) to identify different types of pesticide use trajectories, and ii) to understand the options implemented by winegrowers to reduce their pesticide use. METHODS: We analysed data from 161 farming systems in the DEPHY farm network in 12 French winegrowing regions over a 10-year period. Pesticide use was assessed with the treatment frequency index (TFI). We characterized the TFI trajectory of each farming system with six indicators and built a typology of TFI trajectories. We then analysed several indicators such as the use of biocontrol products and the dose sprayed to identify some of the management options chosen to achieve these pesticide use trajectories. RESULTS AND CONCLUSIONS: Three clusters were identified and characterized in terms of pesticide use strategy. The first cluster represented farms with an initial point close to the regional average and which did not experience a significant TFI reduction (−13%). The second cluster comprised farms with a low TFI when entering the network that were able to further reduce their TFI over time (−48%). The last cluster represented farms with a high initial TFI and a high reduction (−63%). All clusters managed to reduce their pesticide use by combining several technical levers at different intensities. Some differences in the levers between clusters were observed. Cluster 2 farms are in the process of converting to organic farming and using the associated levers such as biocontrol and mechanical weeding. SIGNIFICANCE: The changes implemented by cluster indicate a varying degree of progress in the transition towards pesticide use reduction. The initial point was identified as having a strong influence on the end result. The more intensively the technical levers were combined, the more difficult it was to reduce pesticide use. The DEPHY network supported winegrowers in their reduction of pesticides who managed to reduce their pesticide use by 13% to 63%.