Abstract: Samples of corn southern leaf blight were collected from 10 locations of Hebei province from 1987 to 2003. Among them, 288 strains of Bipolaria maydis were identified with the identification hosts. Results showed that isolation frequencies of Race T, Race C, Type S and Race O were significantly different from each other in respects of both locations and years. Isolation frequency of Race O was significant higher than those of the other races. It is suggested that Race O is the dominant race of B.maydis in the corn-growing area in Hebei province. During the identification period, the isolation frequency of Race C showed significantly different. The pathogenicity of Race O from different areas and years was different. The isolation frequency of strong pathogenic strains of Race O was more than that of the weak pathogenic strains. The strong pathogenic strains mainly distributed in the eastern and southern of Hebei, while the weak pathogenic strains mainly distributed in the northern of Hebei.

Key words: Bipolaris maydis, Physiological race, Identification, Dynamics

CLC Number: 

• S513.01