It's downy mildew. Bane of my existence....and problematic in the hot muggy south with all the rain we've had. It must be treated right away or it will kill your plants eventually. There are lots of ways to control it. I typically use Neem oil because I'm anxious about chemicals.I'm.wondering about these spots on some of the squash and cucumbers. I'm assuming some kind of mildew? Do I need to treat it or just wait for drier weather? Also, anybody know what these plants are? They're pretty neat in my opinion.