neem oil is more preventative, lots of people suggest covering the top in some way but i always had them coming out the bottom of the pots too, using the dunks as a powder on top is how you stop them in the soil, once they are dead the spray and sticky traps should take care of the adults. I had a real bad problem recently, drying out, need oil, apple cider, none of it worked, there was more and more everyday, i felt like you do, but once i crushed up the dunks, sprayed with organicide, and put up the cheap $2 sticky traps they were gone in a few days, i put the traps down low by the plants, mine were coverd after 2 days, hopefully some of that will help.