Close-ups of 12-day-old cotton bollworm larvae on cotton bolls. The smaller larva was fed a diet containing Bt proteins, whereas the larger larva was fed a controlled diet. Diet comparisons are used to track the development of Bt resistance.
In the past, farmers have used toxic chemicals such as calcium arsenate, Paris green, dichlorodiphenyltrichloroethane (DDT), and toxaphene to rid their cotton crops of insects. Today, however, farmers are buying transgenic seeds that have ...