BT, works great on the cabbage worms. They will tear up brassica. There's a white moth that lays the eggs. I was so close to getting a salt gun to shoot the bastards last year. I'd see them in the afternoons, they are territorial I've read. But as soon as I killed one, another would come by. Row covers work if you get them in soon enough. I will be trying. that this year as well as the BT.I'm using the biocontrol for the caterpillars, some sort of powdered bacteria that you mix up with water, kills them really fast and it's not toxic like many pesticides to other insects.
We tend to get bright green caterpillars down here and they go for the tomatoes and brassica family. End of season for our tomatoes and they'll be pulled up in the next few weeks.
I'm going to try and overwinter the Chilli / pepper plants though.