I recently got rust on a daylily which hadn't had it before, and a couple of my older seedlings are looking a little suspicious (not counting the one I think *will* turn out rusty, but which I'm waiting for confirmation on before I pitch it). Not obvious rust, not leaf streak, but sort of lighter colored areas on parts of the leaves. I don't know if that means incipient rust, or if something else is going on.
Those seedlings certainly are fed well enough, so I doubt it is nutritional.
Some years ago (sorry, I can't point to the issue) the Daylily Journal had a really good article with some great images showing the effects on daylily foliage of different diseases and also nutritional problems. I really wish the AHS would take that article and permanently pin it up on the AHS website somewhere, for easy reference.
