I use a time-tested tool: in 3 litr of water add pharmaceutical vial of valerian and 1 tbsp. l. liquid soap.
A month before harvest cabbage heads on cabbage storage sprinkle ammonia. To do this, 1 vial of liquid ammonia (40 ml) should be poured into a 5-liter bucket of water and add a couple of tablespoons of liquid soap. After this treatment will not be any pests.