Monterey B.t. is an easy-to-mix liquid concentrate that kills worms and caterpillar stage insects, but has no effect on birds, earthworms, or beneficial insects such as honeybees and ladybugs, when used as directed. Worms and caterpillars eat treated foliage, then immediately stop feeding and damaging plants. Monterey B.t. is acceptable for use on edible plants up to the day of harvest.