I moved into my house last August. No one has lived here for 10 years, so the garden is pretty much "virgin" soil, if you will. The 1st of March, I planted 25 red pontiac seed potatoes. We went through a couple of weeks of a little cool snap... 65 to 70 degrees, and lots of rain. My potato plants were fine yesterday morning. This afternoon, I went out to water, and 2 of my plants (right next to each other) have these tiny brown spots. They are not holes. There are no insects on the underside of the leaves. PLEASE tell me this is not early blight. What is this?