Abstract
Two hundred fifty isolates of Pyricularia grisea were collected from rice plants in Kanto-Tokai district in 1994. Fourteen pathogenic races were identified based on 12 Japanese differential varieties. Race 007 was dominant in Tochigi, Gunma, Saitama, Chiba, Nagano, and Shizuoka Prefectures, whereas race 001 was dominant in Mie and Kanagawa Prefectures. We observed a significant change from 003 to 007 in pathogenic race composition as compared to the survey in 1976 and 1980 except for Mie Prefecture.
