Several sclerotial fungi isolated from sheath blight-like lesions and their properties

Abstract

Several sclerotial fungi other than the sheath blight fungus, Pellicularia sasakii, were frequently isolated from sheath blight-like lesions of rice plants collected from different areas in Japan in 1979. Those were as follows: Rhizoctonia oryzae (bordered sheath spot), Rhizoctonia solani-culture type IIIB (brown sheath blight) and Sclerotium oryzae-sativae (brown sclerotium). The artificial inoculation of rice plants elucidated that P. sasakii was the most pathogenic followed by R. oryzae. S. oryzae-sativae was moderate and that of R. solani-culture type IIIB was slight in pathogenicity. R. solaniculture type IIIB was identified by hyphal anastomosis to standard isolate and numbers of nuclei in the vegetative hyphal cell. The hyphal cells of the genus Rhizoctonia (P. sasakii, R. solani-culture type IIIB, R. oryzae) were multinucleate (5.7 on the average), while those of the genus Sclerotium (S. oryzae-sativae, S. fumigatum, S. hydrophilum) were binucleate.