Greetings Tom,
Unfortunately, many potential insect and disease questions cannot be diagnosed over electronic correspondence or via the telephone.
Rather than "guess" at your tree's potential ailment, I would strongly suggest you contact a professional tree care specialist (e.g., a certified arborist from the yellow pages) for an on-site evaluation.
As is often the case, the patient (your tree) and the doctor (tree care specialist) simply need to visit each other :-)
