Abstract: The species identity of the pathogen of Phoma stem canker was determined through a combined study of rDNA-ITS sequences. Phylogenetic analysis showed that the isolate clustered together with the isolates of Lepto-sphaeria biglobosa and was distinct from those of Leptosphaeria maculans. ITS sequence analysis indicated the isolate was Leptosphaeria biglobosa. Infection conditions and pathogenicity of Leptosphaeria biglobosa were conducted in controlled environment. The studies indicated that blackleg of oilseed rape frequently occurred under high tempera-ture and high humidity conditions and the pathogen couldn't infect the host when temperature and humidity were unsuitable;Temperature and wetness period cangreatly affect the infection of Leptosphaeria biglobosa,at 21-24℃ with over 48 h of wetness period was the favorite combination of temperature and wetness period for infection,below 48 h of wetness period,disease index decreased with decreasing wetness period and increasing or decreasing temper-ature. As wetness period from 12-72 h,disease index increased with temperature increasing from 15-21℃,but it reduced with temperature increasing from 21-27℃.

Key words: Leptosphaeria biglobosa, Infection conditions, Disease index

CLC Number: 

• S435. 654