My experience with Safer's at the recommended dose with daylilies is that it harmed them. My experience with mild dish soap solutions is that it did not harm the daylilies.
I had an infestation of aphids on daylilies I was testing indoors just after I brought the plants inside in the autumn. I used a mild spray of dish soap and saturated the plants making sure that the solution ran down between leaves. I was surprised, but after repeating the sprays every few days it actually seemed to have worked and the aphids were no longer present for the rest of the long winter.