Abstract: In order to understand the epidemic factors of northern corn leaf blight in northeastern China，the?physiological differentiation and races dynamic of Exserohulum turcium was investigated. Using routine technique，?eighty-eight isolates of Exserohulum turcium，collected from 22 areas of Liaoning，Jilin and Heilongjiang provinces in?2010，was identified on different resistant genes(Ht1，Ht2，Ht3 and HtN). The results showed that 14 races were identified among these fungal isolates，including 0，1，2，N，12，1N，23，2N，3N，12N，123N，123，23N and 13N. The?physiological differentiation of E. turcicum in northeastern China was obvious. And the race infect the maize with all?kinds of resistance genes was appeared. Among these races population，races 0 and 1 were predominant with occurrence frequency of 37.5% and 20.5%. The virulence frequencies against genes Ht1，Ht2，Ht3 and HtN was 45.5%，?30.7%，15.9% and 23.7% respectively. The physiological race component and their inter-specific of E. turcicum variability in northeastern China became complex and new races were frequently found. The increasing epidemic of northern maize leaf blight in northeastern China was ascribed to the continuing occurrence of new races of the pathogen，the?increasing virulence frequencies of such major races as 0 and 1，and the resistance losing of the cultivars.

Key words: Exserohilum turcicum, Physiological differentiation, Identification, Dynamic analysis

CLC Number: 

• S435.13