I guess mildew, a fungus quite common on peas, but the little holes suggest something else as well.
Have they flowered? When did you plant them? The pea usually appears just behind the flower as it withers.
No, some people plant peas in July to crop in Sept. or Oct if the weather holds, a frost finishes them. There is a bit when you don't plant them because of a moth whose caterpillars get into the peas. I can't remember the timings off hand. They may be going to flower soon. You could try a fungicide for the mildew, though most peas seem to get it to a degree. If you do read the label and check what is in it on Google or somewhere, fungi don't die easily and some fungicides are not very nice all round. Maybe someone will come back with a safe recipe for treating such things, I tend to tolerate things unless they gets too bad, then I bin whatever it is, treatments are often not worth the time, expense and pollution.