treehopper vs plant hopper

treehopper and plant hopper both are nouns.

Word	Noun	Adjective	Verb	Adverb
treehopper	Yes	No	No	No
plant hopper	Yes	No	No	No

As nouns, plant hopper is a hypernym of treehopper; that is, plant hopper is a word with a broader meaning than treehopper:

treehopper: small leaping insect that sucks juices of branches and twigs
plant hopper: related to the leafhoppers and spittlebugs but rarely damages cultivated plants

Other hypernyms of treehopper include planthopper.

treehopper (noun)	plant hopper (noun)
small leaping insect that sucks juices of branches and twigs	related to the leafhoppers and spittlebugs but rarely damages cultivated plants