woolly plant louse vs woolly aphid

woolly plant louse and woolly aphid both are nouns.

Word	Noun	Adjective	Verb	Adverb
woolly plant louse	Yes	No	No	No
woolly aphid	Yes	No	No	No

As nouns, woolly plant louse and woolly aphid are synonyms defined as:

woolly plant louse and woolly aphid: secretes a waxy substance like a mass of fine curly white cotton or woolly threads

woolly plant louse (noun)	woolly aphid (noun)
secretes a waxy substance like a mass of fine curly white cotton or woolly threads	secretes a waxy substance like a mass of fine curly white cotton or woolly threads