Botrytis galanthina is closely related to the grey mould pathogen Botrytis cinerea. B. cinerea has a very wide host range, but B. galanthina is one of a number of species which attack specific plants, in this case only Galanthus spp.
Botrytis galanthina forms small, black, seed-like structures (sclerotia) in the tissues it kills. The sclerotia germinate as the new shoots develop, releasing spores which infect and kill the shoots. The fungus produces a fuzzy grey mould which releases airborne spores and these spread infections to new plants. The fungus can spread back down to the bulb and forms new sclerotia on the infected scales.