A pioneering long-term experimental set-up for the epidemiosurveillance of fungicide resistance.

This database has been designed to enable the status of resistance in these populations to be assessed each year as well as the selection pressure associate with the various fungicide treatment programs. All this information is used to draw up recommendations for resistance management, which are passed on to stakeholders in an annual memo to which we are a signatory. In particular, this note makes it possible to avoid applications of fungicides rendered ineffective by resistance, and to propose alternative solutions to chemical control. In addition to being a valuable practical tool for farmers, this database, unique in Europe, is also a relevant and original scientific ressource to explore the dynamics of adaptation over large time and space scales.  During his PhD, Maxime Garnault performed a very comprehensive statistical analysis of that database and provided a quantitative description of the evolution of fungicide resistance of Z. tritici to several modes of action in France (Garnault et al, 2019). He also identified the determinants of fungicide resistance evolution at large spatio-temporal scales, quantified their effects and especially revealed that fungicide use at the regional scale is the main driver of resistance dynamics (Garnault et al, 2021). Besides, this work was complemented by the creation of an application to visualize the state of resistances on a map of France and to forecast their evolution. The hundreds of samples handled yearly for this activity are also the source of original isolates used in other projects exploring resistance mechanisms and enriching our long-term collections.

References:
M. Garnault, C. Duplaix, P. Leroux, G. Couleaud, F. Carpentier, O. David, A‐S. Walker. Spatiotemporal dynamics of fungicide resistance in the wheat pathogen Zymoseptoria tritici in France. 2019. Pest Management Science, 75 (7), pp.1794-1807,⟨10.1002/ps.5360⟩.
M. Garnault, C. Duplaix, P. Leroux, G. Couleaud, O. David, A‐S. Walker, F. Carpentier. Large-scale study reveals regional fungicide applications as a major determinant of 2 resistance evolution in the wheat pathogen Zymoseptoria tritici in France. 2021. New Phytologist, 229 (6), pp.3508-3521, ⟨10.1111/nph.17107⟩.