Insects: Are IRM Plans for Transgenic Corn Endangered?.
Emerson Nafziger, Univ of Illinois, Crop Sciences/W301 Turner Hall, Urbana, IL 61801 and Kevin L. Steffey, Univ of Illinois, Crop Sciences, W301 Turner Hall, Urbana, IL 61801.
Corn hybrids containing a genetic code for insecticidal protein transferred from the Bacillus thuringiensis genome were released for commercial production with the requirement that planting be managed in a way to slow or prevent the development of field populations of target insects with resistance to these proteins. Such mandatory insect resistance management (IRM) guidelines were first imposed on Bt hybrids resistant to European corn borer (Ostrinia nubilalis) and related insects, and more recently, slightly different guidelines were put into place for Bt hybrids developed for management of the western corn rootworm (Diabrotica virgifera virgifera). Although surveys show that high percentages of producers implement these guidelines at present, we think that the continued proliferation of new GM traits, the increasing tendency to have multiple GM traits incorporated into hybrids, and the increasing proportion of fields planted to hybrids with traits that require IRM will make it more difficult for producers to maintain IRM plans.