Resistance to Bt crops emerges
Some caterpillars are cottoning to transgenic cotton.
Genetically engineered cotton and corn produce a toxin that kills caterpillar larvae and other pests, but a new study shows that resistance to this toxin could be spreading among one species of caterpillar.
Farmers worldwide plant more than 400 million acres of these transgenic crops each year. A bacterial gene inserted into the plants’ DNA enables the crops—called Bt crops—to kill insects without sprayed pesticides.
But killing vulnerable caterpillars can drive the evolution of resistance to the toxin, since only the survivors reproduce.