Question
w to cure bark rot

Answer
Edward:
Many things can cause a bark problem- some may not be an bona fide infectious disease.  It would be best to have someone come and make a house call. Suggest contacting your local county Extension office to arrange for a field diagnosis- someone really needs to see the actual problem in person. In many cases, it is possible that other microorganisms, insects, etc can move into a stressed or decayed area and set up housekeeping. This makes finding the original cause very difficult to impossible to determine, leaving us limited options.

Hope this helps with your "detective " work.

Steve