I finally found what has been putting holes in the hop leafs lately. It alluded me for days, yet fresh leaf damage indicated something was still very active on the plant. I had even purchased a pesticide that's safe for plants and vegetables, but either it doesn't work or it has to be sprayed directly on the pest as the leaf damage continued. Finally, on Monday afternoon, I spotted the little bastard making his way up the twine, probably looking for new fresh leaves to eat. Hopefully it was the only one, but I'll keep my eye out for new leaf damage.