What would cause little holes in the leaves of my zucchini plant leaves

Question

The plants were grown from seed, and have looked really healthy until this weekend. Now the most mature leaves have a lacy look, with lots of holes. I do not see any little insects. There is a bit of white or brown around the holes both on the upper and undersides of the leaves — I am actually Zone 2, not Zone 5.

Answer 1

It cold be caused by flea beetles. This article will help if it is that:
https://www.gardeningknowhow.com/plant-problems/pests/insects/what-are-flea-beetles.htm

But the lacy damage you describe is normally more attributed to Japanese Beetles. This article will help with them:
https://www.gardeningknowhow.com/plant-problems/pests/insects/japanese-beetles.htm