Botrytis bunch rot is a major fungal disease of grapevines, and causes severe economic damage worldwide. Under humid climatic conditions, the development of bunch rot on grapes cannot be suppressed completely. Selection of planting material with lower bunch rot susceptibility represents one of the most efficient long-term tools in the complex bunch rot minimisation strategy. The present investigation conducted over four consecutive years (2013-2016) under the environmental conditions of the Moselle valley aimed at (i) detecting consistent differences in the bunch rot susceptibility within a group of nine commercially available Vitis vinifera L. 'White Riesling' clones, (ii) investigating potential underlying causes and (iii) deriving recommendations for 'Riesling' clone selection in practical viticulture. Disease severity and grape maturity (total soluble solids) progress could be well simulated by sigmoidal curves (R2 > 0.89; P