Noun: armyworm 'aa(r)-mee,wurmNoctuid moth larvae that travel in multitudes destroying especially grass and grain - army worm, Pseudaletia unipuncta Moth whose destructive larvae travel in multitudes - Pseudaletia unipuncta Larva of fungus gnat that feed on cereals and other grains; they march in large companies in regular order when the food is exhaustedDerived forms: army worms, armywormsType of