It is conceivable, so to speak, that the bollworm could evolve immunity to its own sex pheromonefor example, by producing a different scent.
So far, the pink bollworm population has not rebounded, indicating that the feared resistance to Bt has not yet developed.
As the pests, such as pink bollworm and aphids, became increasingly resistant to chemical spraying, farmers reacted by laying on even more, sometimes mixing two or more products .