 The diamondback moth was the first insect found to have become resistant to biological control by the Bt toxin (from "Bacillus thuringiensis") in the field.Bt toxin is poisonous when ingested by insects but not mammals, so it was used to target low infestation levels of the moth.Research has shown that the diamondback moth has an autosomal ressessive gene that provides resistance to four specific types of "B. thuringiensis" (Cry1Aa, Cry1Ab, Cry1Ac, and Cry1F).