Greetings Juanita,
I'm not too sure about this mysterious black band; can you send me several high quality digital photos for examination?
Secondly, we have been witnessing some premature leaf drop across the state this summer and early fall. More than likely, this phenomenon is the direct result of summer drought confounded by harsh urban growing conditions. Yard trees, especially in urban environments, require adequate water uptake for sustained growth and vigor. Make sure your yard trees receive proper watering during periods of prolonged drought.