ABSTRACT
Gray mold disease is one of the most important diseases of planted Paris polyphylla var. yunnanensis, the disease appeared primarily as blossom blights and fruit rots, but also as stem rots, leaf rots.In this study, the pathogenetic fungi was isolated from plant tissue or sclerotia that covering the fruit of diseased P. polyphylla var. yunnanensis, the pathogen was certified according to Koch's Postulation. The pathogen produced abundant black, irregular sclerotia on surface of diseased plants and potato dextrose agar. The conidiophores and clusters of oval conidia resembled a grape-like cluster, the size of conidia was 9.70-13.70 μm [average of (11.32±0.82)μm]×7.05-9.12 μm [average of (8.24±0.48)μm], the microconidia produced on potato dextrose agar were spherical,and the size was （3.34±0.31） μm,the pathogen was identified as Botrytis sp based on morphological characteristics. The DNA sequence analysis of the G3PDH, HSP60, RPB2 genes placed the pathogen in a single clade that outside defined species of Botrytis, so the pathogen could be identified as a new species of Botrytis. The pathogen requires 20 °C, pH 8, darkness or low light condition for the best growth.