I’m guessing my sulfur won’t do it; should I get something else? When I see this on fruit trees around town it looks terrible but the trees seem to do OK. (should mention that the picture ought to be rotated 90 degrees.)
My guess is somehow an injury happened to that branch giving fungus opportunity to move in and caused damage. It looks like the tree cannot produce enough healthy tissue to envelop the wound.
I would remove it but will do when the tree is actively growing and during a dry stretch. You don’t want to create another wound from the cut in wet weather. Actively growing trees can fight off diseases better, IMHO.
Well, it was nice yesterday and I went ahead and took it off. And now it’s raining. But we have several days of dry coming up so maybe it will seal off then. I cut it back to a shoot, and it’s still a foot from the trunk, so if it acts up again I still have room to cut it back.