I think a Japanese maple in my yard has pseudomonas. I've attached a few photos. It's only on a few branches, and the picture of the leaves shows the end of those branches- so far they're okay. If I owned this tree, I'd prune all the bad branches out. BUT, I don't, it's a rental property, and some previous pruning caused an "incident" with the neighbors, so I can't really do any more. Should I spray it? Hope the tree can work around these branches? It's about 10 feet tall, 3-4 years old.
Spray with some sort of copper-based treatment, e.g. bordeaux mix, Phyton-27, etc. If it's that size at 3-4 yrs old, it's probably been heavily fertilized. Would be a good idea to stop that altogether.