Hirsutella subulata (Hyphomycetes) was observed for the first time on diseased larvae of Chilo suppressalis in Korea. This fungus formed slender and slightly attenuated synnemata consisting of closely bound, longitudinal hyphae on the insect larvae. Typical characteristics of this species are ellipsoid or broadly obovoid phialides with slender, needle-like necks and asymmetric conidia. It is very similar to H. barberi but can be distinguished by its asymmetrical conidia.