Eleven isolates of Pyricularia zizaniaecola HASHI0KA were isolated from diseased leaves of rice grass(Zizania latifolia TURCZ.). The 3 isolates of P. zizaniaecola sporulated sparsely on oatmeal agar after 25 days at 26C on the darkness or the fluorescent light irradiation. Howeyer, many isolates formed conidia abundantly on autclaved rice grass leaf segments and also on crabgrass leaf segments after 15 days at 26C. The length of conidia was as large as that of P. oryzae, but the width was larger than that of P. oryzae. When rice grass plants were inoculated with conidial suspension of P. zizaniaecola, 1-2days after inoculation the small and discolored spots were produced on rice grass leaves. Afterwards, on the 6th day these lesions began to assume around confomation with a brown-black center.