Well today I was out watering my plants. I fed them last week and another feeding day approaches but today I decided to just water. I noticed my little daisies weren't doing as well as they should be. I was about to write it off to the heat but a closer looks showed a shiny, sticky substance on their leaves. A closer look, yep, aphids. Again.
I got out the insecticidal non-toxic (to us humans anyway) soap. I trimmed back the plant so got most of them off that way, and then sprayed the heck out of it. I made double sure to spray the plant from underneath as well and then sprayed the dirt as well.
It seems that I am able to keep them under control, but they do seem to emerge during the heat of middle summer. I guess there is no getting away from them, but one can keep them in check. Good luck with yours!