Monday, 15 November 2004 - 10:42 AM
0126

Native resistant maize interactions with seed treatments for control of the western corn rootworm

Kelli Barr, klbxr6@mizzou.edu1, Thomas L. Clark, clarkth@missouri.edu1, and Bruce E. Hibbard, hibbardb@missouri.edu2. (1) University of Missouri, Department of Entomology, Columbia, MO, (2) University of Missouri, USDA-ARS, 205 Curtis Hall, Columbia, MO

The western corn rootworm, Diabrotica virgifera virgifera LeConte, is a serious pest of maize, Zea mays L., in the U.S.A. Current methods for controlling rootworm include crop rotation, insecticides and transgenics. While native resistance has been difficult to implement in modern maize hybrids, progress has been made. Damage levels are significantly lower in resistant varieties than susceptible lines but higher than insecticides or transgenics. We examined whether current levels of native resistance could provide acceptable levels of rootworm control when coupled with an insecticidal seed treatment. The experiment was a randomized split-plot design (5 replications) conducted at two sites in Missouri (one with a natural rootworm population, the other manually infested). We evaluated a native resistant population of maize which contained a composite of resistance sources at cycle 0 and after 5 cycles of recurrent selection for reduced larval feeding damage, a modern hybrid with transgenic resistance and its susceptible near-isoline. Each maize line was protected with a traditional granular insecticide, a rootworm seed treatment rate, a secondary seed treatment rate, or no insecticide. Data was collected on root damage ratings (0-3 scale) and adult emergence. ANOVA will be used to examine the interactions between maize pedigree and insecticide treatment. If maize conferring native resistance to rootworm has a synergistic effect with seed treatments then the combination may have utility as an alternative to conventional and/or transgenic control tactics. Furthermore, our results may have important implications when considering refuge requirements and resistance management for recently commercialized rootworm targeted transgenics.


Species 1: Coleoptera Chrysomelidae Diabrotica virgifera virgifera (western corn rootworm)
Keywords: Maize, rootworm

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