I can't see details of the specs on the leaves, but I am pretty sure they are aphids. The white specs are dead aphids, just the shell, so a predator has been at work killing the aphids. Lady beetles love them and are probably present; there may be other beneficial insects such as tiny parasitoid wasps. It looks like they are doing a great job so I would not spray them with an insecticide. Keep an eye on them and make sure the beneficial insects get the majority of the aphids. You can then just spray with a strong stream of water to wash away any left. My day lilies get aphids almost every year and there is always beneficial insects present to control them. I have never needed to use an insecticide.