Reducing pesticide use in vineyards. Evidence from the analysis of the French DEPHY network

High quantities of pesticides are applied on vineyards. For example, the average treatment frequency index (TFI) for French vineyards was 13.5 in 2016, whereas the average TFI for wheat (a major annual crop in France) was 4.9 in 2017. Reducing pesticide use is a key issue to improve viticulture sustainability. The aims of this study were (i) to analyse the evolution of pesticide use in vineyard farms voluntarily participating in a pesticide reduction programme, and (ii) to understand the options winegrowers used to reduce their pesticide use. We analysed data from the DEPHY farm network, including 244 cropping systems followed over 10 years and spread across 12 winegrowing regions. We used the TFI to assess the intensity of pesticide use. Mean pesticide use within the network decreased over the 10-year period and mostly concerned fungicide use. By analysing several indicators such as the number of treatments and the mean TFI per fungicide treatment, we were able to identify some of the management options mobilised for achieving this pesticide reduction. The use of biocontrol products and the reduction of sprayed doses were often associated with a low TFI. The analysis of yield evolution showed a significant mean reduction, although it was smaller than the TFI reduction. This raised the question of the impact of pesticide reduction on productivity. Further trade-off analyses are required in the future.