Just as with all caterpillar pests the standard treatment is Bt dust or spray. Literally hundreds of discussions here about it.

Dave

The holes might be worms. Not a big problem, from the looks of it in your pictures though. The white spots look like a fungal disease. Many "spot" diseases are similar. Actually, "white spot" fungus develops in cooler temperatures, which you probably don't have now. But Anthracnose likes warmth. Copper fungicides are said to work on both. Probably good to deal with it asap because it spreads and will overwinter in the soil.

Thanks, Dan. Very helpful.

I'm going through this right now myself. Those little worms are crazy hard to spot, they blend in so well. Picked off about 7 yesterday and today - some were so small I was staring at them for minutes before realizing it was a worm and not part of the plant. They are sneaky little buggers. I'm using BT now and hope it helps. First time this year I've had this issue.

I pick mostly. Today I caught that rascally grasshopper that I think does a lot of the damage too

That's a lot of wasted Bt in the above image. Should be a very thin film of dust, not a snow storm.

I spray BT, instead of dust. What are the relative advantages of one over the other? Seems to me that a lot of the pests are found on the underside of leaves, and dusting there is kind of impractical. One disadvantage of spray is that it doesn't last a long time. Your supposed to use up what you mix asap.

I had a little trouble figuring out how the powder came out of the bottle at first. My aim was not perfect.

I've noticed over the years that during the autumn garden growing season the old cuke beetles seem to munch on certain fall crops once the summer crops are done. Some of that leaf damage resembles what happens here. I sometimes blame loopers or slugs when it just hungry cuke beetles looking for anything good to eat once the squash and cukes are gone.

I'd believe that for mine except that I wasn't growing squash or cukes.

When I had some of those caterpillars, I found whichever ones I could and fed them to my venus fly traps and pitcher plants.

I get some large eating that isn't worms. I suspect grasshoppers.