One article I read about early blight said, "Despite the name "early," foliar symptoms usually occur on older leaves." I got a chuckle out of that. That sounds like something a plant pathologist would say. A farmer or gardener, on the other hand, might call it early blight if it generally appeared early in the growing season.
I did notice on another plant (in the second potato bed), some black curled edges on a new leaf. I'm not sure what that was, but I removed the leaf and sprayed with neem oil.
Overall the potato plants look pretty good, I think. I mounded the soil around each plant, added more compost (and a little 10-10-10 since I'm only "mostly organic"), and then added some mulch in the form of some of last year's stilt grass that was growing in an untended area.
The problem I have coming up, though, is that I have no suitable place to store the potatoes. My folks always store theirs in the cinderblock building that houses the well. It's in a shady area with a concrete floor, so it's not too hot in the summer and doesn't freeze in the winter, and it's dark.
One might think a crawl space would be good, but ours is susceptible to flooding.