I have an Amur maple that I’ve been allowing to run without pruning since summer because I was hoping to see some nice autumn colors - unfortunately this apparently created a dark, wet environment in the core of the tree that incubated some fungus. The leaves started turning black and dying so I finally gave up and removed around 80% of them today to try to prevent it from spreading. Should I remove all the remaining leaves and start spraying with dormant spray, and will that be enough to get rid of it over the winter? Some of the more tender shoots are also affected, should I remove those? I assumed that if I took away all the leaves it would go away with some spraying - it can’t penetrate into the core of the tree or anything, right?
After some frantic googling it doesn’t look like I have verticulum, just anthracnose. Going to hit everything with a copper spray and make sure I disposed of all the leaves affected.
Did you take a photo before removing the leaves? A number of things can turn leaves black.
if the leaves look awful or have turned color for fall, it’s fine to remove the leaves. If the weather is still warm where you live, you might want to leave the leaves until they start to turn and remove them near the end of the year.
As for the most effective treatment, that will depend on an accurate diagnosis.