Maple leaf disease
I've attached 2 photos of damage to several of the leaves on a mature maple tree. They seem to be more prevalent on the lower branches but I can't tell for sure. Any thoughts? All the damage appears black as it does in the photo.
It looks like it could be freeze damage, especially if the lesions don't appear to be changing shape (getting bigger). If that is what the issue is, there is nothing that can be done and the tree will be fine. There has been a lot of damage here in Madison to plants that normally wouldn't be affected after one cold night in mid-May.
If the damage appears to be spreading, then it likely is a pathogen-caused disease. In that case you should take a sample to your local county UW-Extension office (http://counties.uwex.edu/) and the horticulturist or Master Gardener Volunteers there should be able to offer their opinion. They can also help you send in a sample to the Plant Disease Diagnostic Clinic in Madison if you choose (samples cost $20-25 for diagnosis).