It’s hard to say for sure, but what you describe sounds like powdery mildew fungus, which won’t kill the tree, but can be unsightly and might compromise the tree’s long-term health, if allowed to spread. Go ahead and remove that branch, then monitor to see if the spores are spreading. There are a number of non-toxic products on the market for treating it, and even a few home remedies!
It’s hard to say for sure, but what you describe sounds like powdery mildew fungus, which won’t kill the tree, but can be unsightly and might compromise the tree’s long-term health, if allowed to spread. Go ahead and remove that branch, then monitor to see if the spores are spreading. There are a number of non-toxic products on the market for treating it, and even a few home remedies!