Pathogenicity of rice stem rot fungi, Leptosphaeria salvinii Cattaneo and Helminthosporium sigmoideum Cavara var. irregulare Cralley et Tullis

Abstract

As the result of periodical isolation of rice stem rot fungi during the rice growing season, Leptosphaeria salvinii, one of stem rot fungi, was isolated from diseased plants through the periods, but Helminthosporium sigmoideum var. irregulare, another of stem rot fungi, was first isolated after the heading stage. Similar result was obtained by the isolation of the fungi from the diseased rice plants collected at south plane areas in Saga Prefecture. While, pathogenicity of L. salvinii to sheath was severer than that of H. sigrnoideuin var. irregulare on the test of inoculation to pot cultured plants.