rosette vs russet scab

rosette and russet scab both are nouns.

Word	Noun	Adjective	Verb	Adverb
rosette	Yes	No	No	No
russet scab	Yes	No	No	No

As nouns, rosette and russet scab are synonyms defined as:

Other synonyms of rosette include little potato, stem canker.

rosette (noun)	russet scab (noun)
an ornament or pattern resembling a rose that is worn as a badge of office or as recognition of having won an honor	rhizoctinia disease of potatoes
circular window filled with tracery
a cluster of leaves growing in crowded circles from a common center or crown (usually at or close to the ground)
rhizoctinia disease of potatoes