Three species of Pythium (P. okanoganense, P. vanterpoolii, P. volutum) were newly identified as pathogens of Pythium snow rot of wheat and barley in Japan. From the results on frequency of isolation and pathogenicity, it can be concluded that P. okanoganense is an important pathogen, like P. iwayamai and P. paddicum reported previously by other authors, but both P. vanterpoolii and P. volutum are minor.
