Genome evolution in an agricultural pest following adoption of transgenic crops

Significance Evolution of resistance to management approaches in agricultural landscapes is common and results in economic losses. Early detection of pest resistance prior to significant crop damage would benefit the agricultural community. It has been hypothesized that new genomic approaches could track molecular signals of emerging resistance and trigger efforts to preempt widespread damage. We tested this hypothesis by quantifying genomic changes in the pest Helicoverpa zea over a 15-y period concurrent with commercialization of transgenic Bacillus thuringiensis– expressing crops and their subsequent loss of efficacy. Our results demonstrate the complex nature of evolution in agricultural ecosystems and provide insight into the potential and pitfalls of using genomic approaches for resistance monitoring.