In general, the invention features a method for selecting a transgenic grapevine or grapevine component having increased resistance to a fanleaf disease, the method including the steps of: (a) transforming a grape plant cell with a grape nepovirus coat protein nucleic acid molecule or fragment thereof which is capable of being expressed in the plant cell; (b) regenerating a transgenic grapevine or grapevine component from the plant cell; and (c) selecting a transgenic grapevine or grapevine component which expresses, at a low level, the nucleic acid molecule or fragment thereof, wherein the low level expression increases the resistance of the transgenic grapevine or grapevine component to fanleaf disease. The invention also relates to an isolated nucleic acid molecule encoding a coat protein or fragment thereof of a ‘Geneva’ isolate of a grapevine nepovirus virus.