Certified GKH Gardening Expert
I'm guessing that what you have is an infestions of cabbage worms. Little green worms. The cabbage moth lays her eggs in the lower leaves of any plant in the cabbage family. The moths are the white "butterfly" looking moth that you see flying around in the daytime. Try hosing the worms off or plucking them off. Remove as many of the lower leaves as possible from the plants as this is where the eggs get layed. The eggs are a dark green in color. You can buy cabbage powder to sprinkle on the lower leaves to control this but I am unsure if you can put it right on the parts of the plant that you intend to eat. If you purchase a powder please read the instructions first to see if it is safe to use on all parts of the plant before you apply it.