On the nymphs, insecticidal soap. Pyrethin is also supposed to work on the bugs.

Thanks! I'll check it out.

Does the insecticidal soap actually kill the nymphs or just run them off? I plan to try a mixture of ivory soap and hot pepper "juice" on my squash and pumpkins this year. Last year I learned that the adult squash bugs hang out at the base of the plant, just under the mulch or soil surface. I would water each plant at the base with a hose and squish the adults as they came up. The bugs still got ahead of me so I'll settle with just running them off.

I would use insecticidal soap, not Ivory. Ivory tends to burn plants because it isn't soap, it's a detergent. You can make your own, but you have to find a real lye and oil soap and I haven't seen that in ages (although I am sure it's still out there.)

And yes, the oils in it will suffocate the nymphs, but you have to spray the bugs directly. Just spraying the plant doesn't get you anything.

AFAIK the hot pepper juice doesn't do anything to the insects, so no sense putting it in.