Bacillus thuringiensis (Bt), a bacterium that occurs naturally in soil, has been used by farmers since the 1930s to kill certain insects. It has no effect on humans, animals or other non-target species. Several of the proteins the Bt bacterium produces are lethal to the European corn borer, a common pest that costs the United States an estimated $1.2 billion in crop damage each year. Corn that has been modified to include Bt helps farmers and the environment by reducing the need to spray pesticides on the crop.
Target species for Bt are: European corn borer, Southwest corn borer, black cutworm, armyworm and corn rootworm.
Images courtesy of Iowa State University.