I am not certain, but I think those are aphids. Use the Neem mixed 1 tablespoon to a warm quart of water. Shake the pooh out of it and spray generously on the entire plant right at the end of the photoperiod so as not to burn the leaves.. Spray the soil and the sides of the pots too.

Alternatively, you can go find a mess of ladybugs and let them farm the buggers.