another response....

Neem oil should work well and does not harm the plants. It is also safe to use and does not harm humans in any way. You mix it with mild hand soap and warm water to make an emulsion as you probably know. What you may not know is that there is (or was) a Neem tree farm in Teakettle Village. I am not sure if it is still in operation. I use Neem oil for my orchids and it does a great job of keeping all kinds of insects away from my plants.