Summit’s Biological Caterpillar and Webworm Control is an all-natural, organic solution for controlling leaf-eating caterpillars. The active ingredient is Bacillus thuringiensis subsp. kurstaki (BTK), a naturally occurring bacterium that specifically targets only leaf-eating caterpillar pests of the insect order Lepidoptera, such as cabbage worm, tomato hornworm, tent caterpillar, fall webworm, Gypsy moth, and many more destructive caterpillar pests. The product is an easy-to-mix liquid concentrate and must be eaten by the caterpillar, once inside the caterpillar’s stomach, the bacillus releases a crystalline protein that creates holes in the lining of the insect’s gut, causing the gut to be paralyzed and the caterpillar stops feeding and dies within 1-5 days. It is most effective when used in the early developmental stage of the caterpillars. This product is 100% natural alternative to synthetic insecticides.