potato mildew vs potato murrain

potato mildew and potato murrain both are nouns.

Word	Noun	Adjective	Verb	Adverb
potato mildew	Yes	No	No	No
potato murrain	Yes	No	No	No

As nouns, potato mildew and potato murrain are synonyms defined as:

Other synonyms of potato mildew include potato blight, potato disease, potato mold.

potato mildew (noun)	potato murrain (noun)
a blight of potatoes	a blight of potatoes