I have been picking these tiny little green worms off of my broccoli. They have been leaving holes in the leaves, however my broccoli is doing great. The worms can't keep up with it and I don't have any broccoli heads yet. Are these worms just going to eat the leaves? Or are they going to go after my heads when they come up, also? I am trying to avoid spraying them with BT. I used all of it combating the tomato horn worms during the summer. What do you guys think?