Have you looked at night with a flashlight? (I never do, the thought skeeves me). Maybe earwigs? I blame everything on them.
Last year I had a bug that bothered my tomatoes. It was a flying black insect - not a beetle with an orange top half - not a lightening bug. Very colorful, I don't know the name but they were obvious...

Do as I say, not as I do, huh? By the time it's dark, I'm 3/4 asleep. I did see cucumber beetles on the ground cherry earlier in the season; maybe it's their larvae.

Look into the black vine weevil or other weevils as a possiblity. They are night feeders and I think I have them here.
Here is a link to the fact sheet in NJ.

Here is a link that might be useful: Black Vine Weevil: Life Cycle, Monitoring, and Pest Management in New Jersey