Looks like flea beetle damage. They're tiny black insects that jump away when approached. ( mine do )
You can use yellow sticky tape strung from a stake to another stake about 1 foot off the ground.
Do you like eggplant? Flea beetles LOVE eggplant. They can be used as a trap crop. Also, you can interplant white radishes all over. Flea beetles love radishes, too. Squash bugs don't. Double duty! When they flower, beneficial insects flock to them!
I think I read somewhere that mint, catnip, onions and garlic repel them. Onion and garlic are made into a spray. Mint and catnip can be grown in pots in the garden. If I remember, you use their cuttings as a green mulch. ( I do this with dill and geraniums for squash bugs and cucumber bugs...it may or may not help...I'm a pretty aggressive hand picker. IMHO, it helps.) At any rate, these plants also attract beneficial by the clouds! (Bug cloud that is. The good kind!) Braconids especially like to kill flea Beetles.
Diatomaceous Earth helps, but has to be reapplied after every rain. It has also helped with slugs down deep in my layered mulch.
Neem oil works, too.
Hope this helps.