Doctor right person possibly seen about infestation (3,3)
I believe the answer is:
dry rot
'infestation' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for dry rot that I've seen before include "Degeneration" , "Fungus causing timber decay" , "Usual, customary" , "Fungus attacking wood" , "problem with deal?" .)