Abstract
Fusarium species were isolated from kernels or glumes of scab heads of wheat and barley collected from 202 fields in seven different districts of Japan from 1979 to 1987. Virulence to wheat heads of 273 isolates of five Fusarium species and six cultivars of F. roseum from the kernels and glumes was tested by spray-inoculation. F. roseum ‘Graminearum’, ‘Avenaceum, ’ ‘Culmorum’, ‘Acuminatum’, F. nivale and F. tricinctum caused scab symptoms on the inoculated wheat heads, and virulent isolates of F. tricinctum belonged to F. sporotrichioides and F. tricinctum based on Booth's descriptions. F. roseum ‘Graminearum’ causing scab symptoms was distributed all over Japan. F. roseum ‘Avenaceum’ virulent to wheat heads, however, was isolated from the samples in Hokkaido and Chugoku-Shikoku, while the respective virulent isolates of ‘Culmorum’ and ‘Acuminatum’ were distributed in Hokkaido and Tohoku, and in Tohoku, Hokuriku, Kanto-Tosan and Chugoku-Shikoku, respectively. F. nivale and F. tricinctum virulent to wheat heads were encountered in the samples from Hokkaido and Hokuriku, and from Hokkaido, Tohoku, Hokuriku and Chugoku-Shikoku, respectively.
