Sclerotinia trillii, sp. nov., causing a new sclerotinia disease onTrillium in Japan

Sclerotinia trillii n. sp., which attacksTrillium tschonoskii andT. smallii in Hokkaido and northern Honshu, Japan, is described. The characters identifying this species with the genusSclerotinia are large tuberoid sclerotia, produced both on infected plants and in culture, which consisted of only mycelium (true sclerotia) and flesh apothecia produced on them. This species is distinguished fromS. sclerotiorum, S. minor, S. trifoliorum, andS. nivalis by relatively large sclerotia, cultural colony appearance, and red-brown to yellow-brown, relatively large apothecium, in addition to its parasitic nature onTrillium. Sclerotinia trillii is a psychrophilic having an optimum temperature for mycelial growth at 15–20°C.