I had a lot of them last year. I think I did a good job in handling them they did not cause much damage. The best thing to do since you know they are there is be diligent. You have to search your plants up and down looking for them and then hand pick them off. A good way to find them is look for their poop and also look for defoliated stems. I used to prune off their defoliated stems too afterwards. This way if I see more defoliated stems I know it is new damage and a worm is close by. The only other thing is hope for wasps to get them. Last year I had no such luck. But this year I see plenty of wasps and have seen one actually catch and eat a caterpillar. The other wasp is the one that lays eggs in/on the caterpillar. So if you see like little white cocoons all over a caterpillar leave it alone.