Monterey B.t. Insecticide is an effective natural caterpillar and worm-stage pest control that is safe to animals, people, and beneficial insects like honeybees and ladybugs. The active ingredient is baccilus thuringiensis, a bacteria found naturally in soils. This bacteria paralyzes the target pest’s digestive system, causing them to stop feeding within a few hours of eating the product, where they will die within hours. Monterey B.t. can be used on fruits and vegetables, ornamentals, and shade trees. It can be applied up to one day before harvesting.