Identification of Phoma sp. Detected on Rice Seeds

A Phoma sp. was detected on rice seeds and was identified as Phoma sorghina (Sacc.) Boerema, Dorenbosch ＆ Van Kesteren based on their morphological and cultural characteristics. On oatmeal agar, pycnidia were abundant, solitary, scattered or gregarious, subglobose to flask-shaped, usually with a distinct neck and ostiole, glabrous, blackish-brown, 55∼185 ${\times}$ 40∼170 $\mu\textrm{m}$ in size. Conidiogenous cells were monophialidic, hyaline, subglobose to ampulliform, 3∼5 $\mu\textrm{m}$ in diameter. Conidia were ovoid to ellipsoidal, hyaline, unicellular and measured 3.5∼6.0 ${\times}$ 1.5 ∼3.0 $\mu\textrm{m}$ (usually 4.0∼5.0 ${\times}$ 2.0∼2.5 $\mu\textrm{m}$) in size. Chylarnydospores were variable, uni- or multicellular, intercalary or terminal, solitary or in chains, dictyosporous or botryoid. NaOH spot test was positive on malt extract agar. This is the first report of P. sorghina identified on rice seeds in Korea.