Abstract: The political roadmap about pesticides in France is to reduce quantities by 2, “ifpossible”, before 2018. Research is needed to design and evaluate new pest managementsolutions. A decision workflow system, name GrapemilDeWS was designed, at the plot scale, tohandle grapevine powdery and downy mildews. GrapeMilDeWS stipulates throughout the seasonif and when fungicide sprayings should take place. GrapeMilDeWS has been experimented on anetwork of plots in different French wine regions. We give some results about the number ofsprayings generated by GrapeMilDeWS and the crop protection performance obtained. Wediscuss methodological aspects such as partnership and data required to test and check suchdecision system.