cutworm vs army cutworm

cutworm and army cutworm both are nouns.

Word	Noun	Adjective	Verb	Adverb
cutworm	Yes	No	No	No
army cutworm	Yes	No	No	No

As nouns, army cutworm is a hyponym of cutworm; that is, army cutworm is a word with a more specific, narrower meaning than cutworm:

cutworm: North American moth whose larvae feed on young plant stems cutting them off at the ground
army cutworm: larvae (of a noctuid moth) that travel in large groups and destroy grains and alfalfa in the midwestern states

Other hyponyms of cutworm include Chorizagrotis auxiliaris.

cutworm (noun)	army cutworm (noun)
North American moth whose larvae feed on young plant stems cutting them off at the ground	larvae (of a noctuid moth) that travel in large groups and destroy grains and alfalfa in the midwestern states