Botrytis bunch rot of grapes is mainly controlled by applying fungicides at three crop stages: the end of flowering (BBCH 68), bunch closure (BBCH 77) and the beginning of veraison (BBCH 81). The phenylpyrroles derivative fludioxonil is among the most effective fungicides registered to control Botrytis cinerea. Its effectiveness was investigated in relation to spray timing, fungicide resistance and defence responses of grapevine. Frequencies of B. cinerea strains which were resistant to fungicides were evaluated at harvest. The frequencies of resistant phenotypes were similar in all treatments except for a class of multidrug resistant strains (MDR 1) whose frequency increased after fludioxonil applications. None of the treatments tested induced defence responses in flowers/berries after fungicide application, suggesting that fludioxonil effectiveness was not related to a stimulation of plant defence processes. The standard program of three fungicide applications provided the best control of B. cinerea in the Champagne region in comparison with a single treatment of fludioxonil at any of the crop stages tested.