In the wider definition, there is no difference; they are the same. In a narrower definition also used, a verb phrase is only part of the predicate-- it includes only the direct verbal forms (auxiliaries, participles, etc): I have been skiing all

Grammarians are in agreement that there is a difference between a participle and an adjective, but that difference lies in their use, not in the form of the words themselves. That means that you can't always tell the difference between them