The Ceratovacuna aphids are one of the major gall-forming aphids. Four Ceratovacuna aphids have been reported from East Asia including Taiwan, Korea, and Japan. In Korea, only one species, Ceratovacuna nekoashi (Sasaki), has been confirmed amongst the four species, and yet their colonies have been found only from the banana bundle or cats-paw shaped galls on the primary hosts, Styrax trees (Styraceae). Colonies on the secondary hosts (Gramineae) have not been seen from Korea nor confirmed from Taiwan, although they are usually seen from Japan limitedly on stiltgrass Microstegium vimineum. Recently in Korea, a colony consisting of an emigrant and first instar soldiers were found from a grass species, Seteria sp. that have not been reported as a secondary host of C. nekoashi. Identity of C. nekoashi is definite based on morphology of the first instar soldier. Genetic identity is being explored for confirmation.