MODELING THE DYNAMICS OF ADAPTATION TO TRANSGENIC MAIZE BY EUROPEAN CORN-BORER (LEPIDOPTERA, PYRALIDAE)

A deterministic population dynamics model was modified to include sing le-locus, 2-allele genetics to simulate strategies for delaying resist ance in the European corn borer, Ostrinia nubilalis (Hubner), populati on to transgenic maize. We evaluated seed mixtures of transgenic and n ontransgenic maize, B-row strips of nontransgenic plants, adjacent but separate refuges of nontransgenic maize, and rotation of nontransgeni c and transgenic maize. We studied how the choice of hybrid, planting time, and weather may influence the selection of a tactic for delaying resistance to transgenic maize. Our results indicate that separate re fuges are superior to seed mixtures for delaying resistance. If a high toxin dose cannot be achieved and a small fraction of homozygous susc eptible and heterozygous European corn borer neonates survive on trans genic maize, then resistance can develop in 10-33% of the time require d under the assumption of a successful high dose that kills all hetero zygous neonates. Planting e-row strips may be as good as separate refu ges in delaying resistance, but their adoption carries greater risk be cause of the uncertainty surrounding movement and survival of neonates . The use of transgenic hybrids is the same whether or not they expres s the toxin gene in silks and kernels of maize ears. Toxin titer decli ne must be studied because our simulations indicate that development o f resistance may be greatly hastened by this process.