Answer: It sounds as though gall mites have attacked the leaves of your grapes. These are microscopic insects that lay their eggs on the surface of the leaf tissues. The result is little red humps on the leaf, sometimes raised on tiny little stems. The affected leaf tissue eventually dies, leaving holes in the leaves. There is nothing that you can do now, because the mites are gone. Do rake up any fallen leaves though, and be sure to discard the canes you prune off (don't put them into the compost pile) and you'll help get rid of any eggs they have laid on the leaves or canes.
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