Identification and characterization of Botrytis medusae , a novel cryptic species causing grey mould on wine grapes in Australia

In a collection of 735 Botrytis isolates sampled from Australian wine grape‐growing regions, a single isolate from clade I and group I (based on Bc‐hch RFLP analysis) was found. As many Botrytis species are known to live sympatrically, it was hypothesized that this isolate might be a new Botrytis species. After phenotypic and molecular assays supported this hypothesis, the species was designated B. medusae . Phylogenetic analyses using the nuclear genes G3 PDH , HSP 60 , RPB 2 , NEP 1 and NEP 2 consistently placed B. medusae in an early‐diverging clade I Botrytis spp. lineage. Botrytis medusae produced white aerial mycelium, grew faster at 30 °C and produced long‐branched conidiophore extensions, compared with B. cinerea and B. pseudocinerea . Botrytis medusae was only able to infect wounded grape leaves and was significantly less virulent on wounded leaves and berries than B. cinerea . Botrytis medusae also lacked villiform appendages on the conidial surface and long conidiophores, which are defining features of B. sinoviticola and B. californica , respectively. Identification and characterization of new cryptic Botrytis species living in sympatry on grapevines could potentially provide information to assist disease management strategies for B. cinerea .