Definitions for jointwormˈdʒɔɪntˌwɜrm
Random House Webster's College Dictionary
a chalcid larva that feeds within the stems of grasses, often forming a gall at a joint.
Ref: Also called strawworm. 2
larva of chalcid flies injurious to the straw of wheat and other grains
The larva of a hymenopterous fly, found in gall-like swellings on wheatstalks, usually around the first joint.
the larva of a small, hymenopterous fly (Eurytoma hordei), which is found in gall-like swellings on the stalks of wheat, usually at or just above the first joint. In some parts of America it does great damage to the crop