Good old diotamaceous earth will kill all bugs including ants. It is not toxic, can be spread around the base of the plants, if they are flying bugs then you could actually dust them with it and rinse it off later. You dont want to be breathing this microscopic dust but if it is food grade it is alright to eat it. The very sharp edges of the fossil dust is what kills the insects. Cheap at any garden store, Lowe's etc.