Evaluation of Conventional Resistance to European Corn Borer (Lepidoptera: Crambidae) and Western Corn Rootworm (Coleoptera: Chrysomelidae) in Experimental Maize Lines Developed from a Backcross Breeding Program

Plant resistance is a promising control method for the two mostdamaging insect pests of maize, Zea mays L.: the Europeancorn borer, Ostrinia nubilalis (Hübner), and thewestern corn rootworm, Diabrotica virgifera virgiferaLeConte. Fifteen experimental lines of maize, derived from a backcrossbreeding program designed to introgress resistance to European cornborer from Peruvian maize into two U.S. Corn Belt adapted inbred lines,were evaluated for resistance to European corn borer and western cornrootworm. The experimental lines were in the second generation ofbackcrossing. All experimental lines were resistant to leaf bladefeeding by European corn borer. These lines had low levels of2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one, a chemical commonlyassociated with leaf blade feeding resistance, indicating that this wasnot the mechanism of resistance to leaf blade feeding in these lines.Eleven experimental lines were resistant to leaf sheath and collarfeeding by European corn borer. Useful sources of European corn borerovipositional nonpreference and root feeding resistance to western cornrootworm were not identified. Some of the lines evaluated in this studymay provide useful sources of resistance to both leaf blade and leafsheath and collar feeding by European corn borer.