I noticed this last year, but just thought it had been scorched by lightening. The branches did fine with healthy leaves. I was out pruning and thought that the blackened area had enlarged, and noticed the white mold-like stuff, so I cut it off - again, the branches extending from it looked healthy, and buds were swelling (everything is way too early this year).

Then I noticed a similar blackened spot on another apple, in the crotch of a branch.

What could this be?

The trees do get sprayed with antifungal after leaf drop, and again late winter (a few weeks ago) - haven't had any more fireblight or peach leaf curl since I started doing that. These are dwarf to semi-dwarf (pruned smaller) in large pots. They are several years old and produce fruit (which the critters feast on).

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