病原菌为Gerlachia oryzae (Hashioka et Yokogi) W. Gams称稻格氏霉,属半知菌亚门真菌。异名:Rhynchosporium oryzae Hasioka et Yokogi; Fusoma triseptatum Sacc; Fusarium nivale (Ces. ex Sacc.)。分生孢子梗极短,无色,分生孢子短新月形或纺锤形,大小8.4-16.8×2.6-4.9(μm),无色单胞或双胞至四胞。有性态为Monographella albescens (Thümen) Parkinson, Sivanesan et Booth=Phragmosperma sp.; Micronectriella (Calonectria) valis (Schaffn.) C. Bvoth; Metasphaeria albescens Thümen,均属于囊菌亚门真菌。子囊壳黄褐至暗褐色,球形或扁球形,大小172×71μm;子囊圆柱形,大小44.7-70.3×8.5-13.2(μm),内生子囊孢子8个,平行交错排列,子囊孢子椭圆形,有3个隔膜,大小14.9-26.4×3.6-6.4(μm),无色。