University of Hawaii at Manoa
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Bacillus thuringiensis (Bt)

What is it?

Bacillus thuringiensis (Bt) is a bacterium that produces crystal proteins which are toxic to many species of insects. Bt is ingested by the insect and the toxin breaks down the gut lining; spores are then activated causing death within a few days. Bt is an organic method of pest control. Because the toxin is pest-specific you must match the target pest species with a particular Bt toxin protein. In other words, there is not one kind of Bt that works on all pests. You must match the Bt protein to the pest.


Kendal Lyon, Hawaii Island Master Gardeners