There is no typical skeletonizing in your images.

The common Grape Leaf Skeletonizer is not associated with webbing, so your caterpillars may be Leaf Tiers or Leaf Rollers, too small yet to deform the leaves. In any of the above, Bt would be effective. The adult moth that layed the eggs may well be done for the season, so picking off the leaves might be the end of it.

The damage is old, not ongoing.

I have it on my himrod grapes. I did nothing. It did not affect the quantity or quality of the harvest

Thank you all for your input. Glad to hear it is not going explode into a major problem! I will remove the damaged leaves but put a few in a box as Konrad suggests... Might be interesting to find out what these little guys grow up to be.

The pest you want to be careful of with fruit trees is tent catepillars. They can defoliate a tree in a hurry and are very common here in Kansas. they don't typically pick on grapes.

Clarkinks, thanks for the photo. I will watch for them on my trees. I have found a half dozen or more leaves with worm damage on my grapes, so they don't appear to be multiplying very quickly. I did get them sprayed with Bt, but probably missed some. Thanks!

Glad to help out