I sprayed the plants completely, but not so much the soil as I only saw them on the plants, and used the dilution listed on the bottle, maybe a touch weaker. I also physically removed as many as I could, but if you have more than a few neps infected, that could be tedious. But the spray seemed to kill them. I think the key was to do a few applications, a few days apart, to kill any stragglers and newly hatched ones. Good luck!