Later, Tim hollered "What happened to the grape?" and one of our grape plants was COMPLETELY defoliated. Not one leaf left! We looked at the others (we have three grape plants) and found a few more of the creepy worms. We picked them off, sprayed some neem, and will keep watching for them. I'll also be spraying the tomatoes with neem and hope that keeps them away.
Where do these things come from???
These grape vines are being grown tall to grow overhead on a trellis that is not yet built. It will be a roof over a small patio area. Hopefully this poor grape has not met its fate, and will survive this ordeal!