wheatworm vs nematode

wheatworm and nematode both are nouns.

Word	Noun	Adjective	Verb	Adverb
wheatworm	Yes	No	No	No
nematode	Yes	No	No	No

As nouns, nematode is a hypernym of wheatworm; that is, nematode is a word with a broader meaning than wheatworm:

wheatworm: small roundworm parasitic on wheat
nematode: unsegmented worms with elongated rounded body pointed at both ends; mostly free-living but some are parasitic

Other hypernyms of wheatworm include nematode worm, roundworm.

wheatworm (noun)	nematode (noun)
small roundworm parasitic on wheat	unsegmented worms with elongated rounded body pointed at both ends; mostly free-living but some are parasitic