Looks like they're tending black aphids. Time to call in the good guys...unless your intention is to use daisies as a trap crop. ;)

Thank you! I actually just noticed (with a closer look to the photo) the aphids and came back to post the same.

Any suggestions on the best bug to release?

I could do ladybugs but they don't seem to stick around. My mother-in-law's house is overrun with them in the thousands, but I rarely see one here.

I had good luck with using ladybugs on our plum tree, but you're right that they will move on when they're full... I left the ladybugs in the bag below the plum tree for two days, sprayed the tree with forceful water the 2nd evening, and released the ladybugs. I think the trick was leaving the bag out so they were used to that spot.

A more permanent and pesticide free option would be Neem Oil or Paraffinic Oil. I haven't used Neem but see it recommended all the time here. The owner at my nursery recommends the Paraffinic Oil (we're using this weekend). Since the aphids "breathe" through their pores, the oils suffocate them. Hope this helps...

Squish 'em -- revenge is good. Or use direct hits of insecticidal soap.

I see no sign of Aphids and the ants are doing no harm to the plant so there is no reason to harm them. Save the time and energy you would expend on these ants for something that is a real problem.

The ants moved their herd shortly after I took those photos so I'll have to look for them around the garden. I think I will buy some lady bugs, the kids will enjoy watching them. If they leave, I'll look into something else.

At this time the slugs are hurting those daisies more than anything else.

Here's a closer image of the "herd"(click to enlarge)...

If you release winged predators, they won't necessarily go where you want them. It might be better to collect eggs if you can spot them. I'm sure I've accidentally brushed off some ladybug eggs and larvae since I started gardening. I like baby lacewings because their eggs are easy to spot and they stick aphid shells to their backs to hide from ants.

Kimmsr, dear....it's time to put on your Mr. Magoo glasses. Her plant is loaded with aphids, lol.

I had that problem last year. The ants would chase away the ladybugs. I watched them attack the ladybugs. Grrr. Decided that I just couldn't care that the aphids were attacking some annual ornamental flowers and left them alone. They were a good distance from my veggie gardens so I left them be. Was fine. I've moved now, so....perhaps they're someone else's worry now. ;)