Real Dictionary

jointworm in British English
the larva of a genus (Harmolita, family Eurytomidae) of small wasps which attack grain stems and cause galls to form in the joints
noun: the larva of any of several chalcid flies of the family Eurytomidae, esp. of the genus Harmolita, that feeds within the stems of grasses, often causing a gall near the first joint
noun: the larva of chalcid flies of the genus Harmolita, esp H. tritici, which form galls on the stems of cereal plants