Dear teachers,

Would you please tell me how you would parse the following compounds ?

- However, do not overwater or let the plant sit in water since they are susceptible to (a) root rot and there is no "cure" for (b) root rot.

- The disease which infected the trees is (c) root rot.

a) compound verb made up of "root" a noun used as an adverb (?) + "rot" verb.
b + c) compound nouns made up of "root" a noun used as an adjective + "rot" noun.

Thank you for your help and best wishes.