Bacillus thuringiensis kurstaki

Subspecies of bacterium

Bacillus thuringiensis subsp. kurstaki (Btk) is a group of bacteria used as biological control agents against lepidopterans. Btk, along with other B. thuringiensis products, is one of the most widely used biological pesticides due to its high specificity; it is effective against lepidopterans, and it has little to no effect on nontarget species. During sporulation, Btk produces a crystal protein that is lethal to lepidopteran larvae. Once ingested by the insect, the dissolution of the crystal allows the protoxin to be released. The toxin is then activated by the insect gut juice, and it begins to break down the gut.

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