corn earworm vs bollworm

corn earworm and bollworm both are nouns.

Word	Noun	Adjective	Verb	Adverb
corn earworm	Yes	No	No	No
bollworm	Yes	No	No	No

As nouns, bollworm is a hypernym of corn earworm; that is, bollworm is a word with a broader meaning than corn earworm:

corn earworm: larva of a noctuid moth; highly destructive to especially corn and cotton and tomato crops
bollworm: any of various moth caterpillars that destroy cotton bolls

corn earworm (noun)	bollworm (noun)
larva of a noctuid moth; highly destructive to especially corn and cotton and tomato crops	any of various moth caterpillars that destroy cotton bolls