Bonide Products 803 Thuricide BT Insect Killer, 16-Ounce 16 oz., Concentrate, Thuricide BT Killer Contains .8% Kurstaki Certified Organic Thuricide is a liquid formulation of bacteria, Bacillus Thuringiensis (Bt), which is specific to leaf eating caterpillars Controls caterpillars, loppers, cabbage worms, and leaf rollers Insects stop feeding, and die within 2 to 3 days of consuming product