Could be fireblight or something else call black spot. There is another fungal infection that focuses on tree wounds from the wind rubbing cages, insects, or pruning. In any case a good anti-fungal is the solution. Bonide's copper spray probably would work good there. Also works good on peach leaf curl and cedarr apple rust.
I got to spray this week somehow, Already got caterpillars on almost every tree. Got to check the ones I sprayed copper on. I spot sprayed a caterpillar tent nest on a mature tree a few weeks ago. Used wasp / hornet spray.