Daylilies are by far one of the most popular perennials for Kentucky landscapes and there is no doubt there are plenty planted. I just wanted to make you are aware that a tiny sucking insect called an Aphid is enjoying your daylilies as you read. Their damage can develop into a major problem if controls are not taken. But first lets talk about scouting the beds and knowing what is going on. When you look through the daylilies what you may find is a white papery looking material on the surface of the leaves. This will be small and scattered about the plant. these are the exoskeleton of the aphid and was discarded when they molted. Seeing these signs will indicate that you have a population of aphids present. The other thing I hope you see is Lady Bug activity. Lady Bugs are notorious aphid killers and can control small populations of aphids.
So now for the decision; if the daylily looks green and healthy especially at the crown of the plant and your are seeing plenty of lady bugs then let them work. If you see plenty of sign of aphids, low amount of lady bugs and the center of the plant seems weak in color (yellow) then a decision to spray an insecticidal soap should be made. For more information on this subject see Aphids