Green Step II™ is a naturally occurring bacterium (Bt) that controls worms and caterpillars on edibles, ornamentals and shade trees without affecting birds, earthworms or beneficial insects. Best results are obtained by treatments when worms are actively feeding on treated, exposed foliage. Acceptable for use on edible plants up to the day of harvest, apply when worms or caterpillars are first noticed and repeat every 5-7 days while active—more frequently if needed. One of the most effective treatments against Imported Cabbage Worm and Cabbage Looper. 16 oz. Makes up to 32 gallons.