QuestionsHow to growVegetable GrowingSummer cabbagecabbage root fly 0 Vote Up Vote Down Harriet Browne asked 14 years ago Is there anything you can do to kill the larve of cabbage root fly. Or is it just preventing the fly from laying its eggs in first place using netting or cabbage collars? 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 7 years ago Usually the damage is done when the problem is noticed and it best to prevent, and assume that attacks will happen.