I have a seven year old Blue Concord vine, and for the past three years, I have noticed on the underside of the leaves, there have been "spider web" like masses w. black eggs inside, and where they are, the leaves are curled and folded over. I have no idea what this could be, but this year, I want to nip it in the bud (pardon the pun) before the situation returns.

Anyone have any clue what I'm talking about, or what can be done as preventative maintenance?