Why Do I Need Bt in My Garden?

B.t. a natural insecticide that does not kill insects quickly but in a day or two.

It kills ONLY the larvae (grub or worm form) of adult insects that become moths or butterfly pests. Most adult forms of moths that are garden pests do their damage in the larva stage, not the adult. The primary mission of the adult is to mate and lay eggs.
Bt (this is the Kurstaki form) is applied to plant leaves and when larvae eat the sprayed plant part, it takes Bt into its body. Within a few hours the Bt infected larvae stop feeding. The Bt is activated inside the insect where it creates holes in its gut. Death is caused by this bacterium (Bt) cannibalizing the insect. Death occurs within a couple days.

There are several forms of Bt. The Kurstaki form is commonly used by home gardeners for controlling tomato fruitworm, corn earworm, hornworms, cutworms, armyworms, tent-leaf caterpillar, grape leaf skeletonizer and tobacco budworm among others. It is sprayed near emerging seedlings or small transplants; tomato fruit for tomato fruitworm damage; corn silks for corn earworms; grape leaves for grapeleaf skeletonizer and other applications.

• Apply on the soil surrounding young seedlings and transplants to protect them from cutworms.

•  Apply to corn silks as soon as the silks emerge and repeat it about every three days as the silks get longer.

•  Apply to the undersides of grape leaves to kill the grapeleaf skeletonizer and hornworms.

•  Apply to tomato fruits when they are forming to control tomato fruitworm from burrowing into green fruit.

•  Apply to petunias and other flowers as the flower buds are forming to prevent tobacco budworm.