Ants have colonized my birch tree. I believe there are aphids on a neighboring tree. So, what to do? Should I paint the birch with the stuff that keeps ants from climbing trees? Will insectisidal soap get rid of most of the aphids? Don't want to use chemicals.

I have never been able to find the nest of these ants, which live in the back of my garden. Bet I will find it when the garage is taken down, though . . .