The daylilies had been whacked when I bought them and I planted them in pots and they got ratty. So I whacked them again and planted them out and they came back beautiful. I don't whack them very often and I just thought of it as pruning. I prune all the evergreen grasses and stuff like that here in the early spring, to cut off the ratty foliage and it grows new foliage.
If you suspect a fungus and you do not want to use chemicals then try a milk spray. It is very safe and effective. You can Google it. Also aspirin water will boost the immune system and is just plain good for plants in general. You can use a stronger dose and get rid of rust too. I will look for the article but you will like it and it is very safe for the environment.
http://www.plantea.com/plant-a...
