Rotenone is safe for eliminating them.

Try floating row covers in the spring as a preventative to many of the destructive insects.

Sunny,
Do you mean the powder rotenone? I can use that when the plants are not in bloom, but the bugs come when the flowers are out. Row covers do not work well unless you have irrigation under the covers, or at least not for me. I have tried those on ornamental kale to prevent the cabbage looper and my plants did horrible, but perhaps it was not the right thickness. Do you have drip irrigation?
Cheryl

Cheryl - I was replying to you last night when my browser just up and quit. I took that as a hint that it was time for me to go to bed!

Yes, I use drip. And liquid rotenone when needed, but that isn't always the solution when you need to harvest. Doesn't it always seem that the little rascals are always one step ahead of us, and the beneficials a day late!

Let me know if you find something that works well at harvest. Prevention is key, but the question is, what do we do when prevention doesn't work, or doesn't work well enough? Maybe someone smarter than you or I will have the answer!