Pests Overwhelm Bt Cotton Crop

Thousands of acres of cotton bioengineered to make its own insecticide have fallen victim in the southern United States to cotton bollworms, one of three pests that the crops were supposed to kill. The result has heightened the fears of environmental activists that the insects will eventually develop resistance to the toxin, known as Bt, and that fear has revived calls for tougher federal biosafety regulations. The reasons behind the disappointing results—involving one of the first large-scale plantings of a transgenic crop—also serve as a reminder to researchers that Mother Nature still has a few tricks up her sleeve.