中文摘要：

双荚槐是从国外引入我国长江三角洲地区的园林绿化木本植物，其植株在9月下旬至次年1月上旬会发生严重的白粉病，经连续4年的野外观察研究表明，该病由野百合粉孢引起，在江苏句容地区不产生有性世代。该项研究系统地报道了双荚槐白粉病的症状，病原菌的形态学特征，分生孢子的萌发特性，并进行了致病性试验及其有性世代的观察。而首次报道了双荚槐为野百合粉孢的新寄主植物。对此真菌的研究也为我国之首报。

英文摘要：

Cassia bicapsularis is an introduced ornamental shrub in the Yangtze River Delta area. Severe powdery mildew occurred on C. bicapsularis from late September to first ten days of January in next year. Based on continu- ous field observation and study of 4 years, it was found that the powdery mildew was caused by Oidium crotalariae. This pathogen did not develop teleomorph under field observation in the last four years on Jurong area of Jiangsu province. The present study systematically illustrated the symptoms of the disease, the morphological characteristics of the pathogen, the germination of conidia, the pathogenicity test was conducted and the sexual generation was ob- served. It is the first report that Cassia bicapsularis is the host plant of Oidium crotalariae, it is also the first study report in China on the study of this fungi.