Bacillus thuringiensis kurstaki (Btk) is a gram-positive, rod-shaped bacterium native to the soil in a wide range of regions globally. A subspecies of Bacillus thuringiensis, Btk controls Lepidoptera. This order includes gypsy moths, cabbage loopers, tomato hornworms and grape leaf skeletonizers.
One of the many advantages to using Btk is that it does not pose a threat to other animals or insects outside of the order Lepidoptera in the environment once it has been sprayed or ingested by the target pest. Similar to Bacillus thuringiensis israelensis, birds and other predators can feed on the infected pests without ingesting toxic chemicals. As with most biological control measures, Btk applications will be most effective when made early in the pest's life cycle, particularly during the larvae's 1st and 2nd instars. Once ingested, the alkaline environment of the caterpillar's digestive system triggers the Btk bacterium to release a crystalline protein, a type of endotoxin, which paralyzes the caterpillar's digestive tract. The caterpillars will stop feeding and die shortly after this occurs.
Btk is not an effective control for corn earworm or squash vine borer.
Please give us a call at 1-800-827-2847 if you have any questions about Btk, its uses, targeted pests, etc.