Incidence, aggressiveness and In planta interactions of Botrytis cinerea and other filamentous fungi quiescent in grape berries and dormant buds in Central Washington State

Recovery of quiescent filamentous fungi from non-symptomatic grape berries and dormant buds demonstrated dominance of Alternaria , Aureobasidium , Cladosporium , Ulocladium and other dematiaceous hyphomycetes. Up to 78% of berries contained fungi prior to harvest. Botrytis cinerea was recovered from 0.2 to 0.5% of surface-disinfested berries just subsequent to fruit set, and 1.6-4.8% of surface-disinfested, over-wintered dormant buds. In laboratory inoculations of mature grape berries with strains of Alternaria , Aureobasidium , Cladosporium , Ulocladium and Botrytis , only the latter was aggressive in rotting berry fruits. Inoculations with B. cinerea alone and in combination with strains of Alternaria , Aureobasidium , Cladosporium and Ulocladium recovered from grape demonstrated that prior occupation of wound sites by the latter fungi resulted in reduced lesion size compared to inoculation with B. cinerea alone.