I think the yellow spots might be aphid eggs put there by the ants. (Ants are great farmers.) Spray off the yellow spots with water and then get some DE - Diotomacious Earth. Sprinkle the DE all over the ground under and around the plants. DE isn't a poison per se but rather is a tiny crystal that gets in the ants joints and breathing tubes and kills them... they won't cross it, thereby keeping the "farmers" off the plants. The DE will have to be applied when old is washed away by rain, so get a big bag.

Eggs.. never thought of that.

The ants are very efficient, it's almost like an organized invasion. No leaves left unturned, so to speak...