Abstract: Artificial inoculation of Ustilaginoidea virens (Cooke.) Tak. cultured in vitro was made by injecting at nightfall during booting stage of rice . The mixture of hyphae broken and conidia of the pathogen could cause serious disease of false smut. The maximum percentage of infected panicle(PIP) was 100 %, the maximum number of spore balls(NSB) of a panicle was 106, and the maximum disease index(DI) was 85.5. Disease severities caused by different strains, and disease severities of different rice materials caused by the pathogen were different; and there was obvious correlationship between DI and PIP, and between DI and average NSB of a panicle. It seemed that there existed specific interaction between strain and variety.

Key words: Ustilaginoidea virens, hyphae, conidia, pathogenicity, artificial inoculation

摘要： 在水稻孕穗期于傍晚用注射法人工接种培养的稻曲病菌，发现病菌菌丝碎段与孢子混合可引起水稻严重发病，最高穗发病率可达100%，最多穗病粒数达106粒，最大病情指数达85.5。不同菌株引发的病情差异很大；病菌在不同品种上引发的病情也差异悬殊；病情指数与穗发病率之间及病情指数与穗平均病粒数之间存在高度相关。初步发现菌株品种之间存在专化互作现象。

关键词: 稻曲病菌, 菌丝, 分生孢子, 致病力, 人工接种