not fire blight....but almost appears to be a fungus. does not appear to be black knot though either...from my handbook i couldn't identify.....if it is me i'm trimming that piece away few inches from source and then using pruning compound over the open wound
Looks like the “thing” I removed from an apple tree this spring prior to green up. Knock on wood but I haven’t had any tents this year whereas I’ve had them the last several years.
So, I have actually left this on the tree. I check it every day because I want to confirm what it is. My fear is I will come out one day and the tree will be bare...
Looks like tent worms to me. My bet is that, left unattended, they will over winter and hatch to coincide with spring greenup, where upon they will have the potential to devour a large portion of new growth. Tent worms are now out of season here in Michigan, however, this year I have seen a late summer variety. I just dusted several oaks last weekend. The worms were dead the next day.