What is causing our maple trees to have black spots on the leaves?

Question: Our maple trees have big black spots on the leaves. My guess is it’s a fungus; is that likely?  For now, assuming it’s a fungus, what’s the best product to treat it with? The maples are fairly new and small, so spraying would be possible. Photo used with permission from read more What is causing our maple trees to have black spots on the leaves?