1998 ESA North Central Branch Meeting Abstract
61 WESTERN CORN ROOTWORM: RESISTANCE MANAGEMENT ISSUES EMERGING IN NEBRASKA. Lance J. Meinke and Blair D. Siegfried, University of Nebraska, Department of Entomology, Lincoln, NE 68583
Results of research conducted from 1994-1997 have documented that adult western corn rootworm populations have become resistant to methyl parathion and/or carbaryl in two separate areas of Nebraska. A strong relationship exists between increased tolerance, field control failures, continuous corn, and long-term use of adult management programs. To date, organophosphate or carbamate resistance in adult western corn rootworm populations has not been documented in any other part of the Corn Belt. The resistance problem is significantly impacting adult corn rootworm management options and is changing management practices in the affected areas of Nebraska. Aerial applicators are experimenting with new insecticide tank mixes; a strong interest exists in finding economic alternatives to currently used methyl parathion formulations. Many crop consultants in the affected areas are recommending changes in rootworm management practices to clients (i.e. crop rotation, soil insecticides). Questions have been raised about the relationship between adult and larval corn rootworm susceptibility to insecticides. Larval progeny from methyl parathion resistant adults also exhibit resistance to methyl-parathion, although cross-resistance to other organophosphates, carbamates, and pyrethroids used as soil insecticides is variable. For example, within the organophosphate class, larvae are much more tolerant to methyl parathion than other organophosphate compounds (i.e. chlorpyrifos, terbufos). Limited field data/observations indicate that many soil insecticides currently provide adequate larval control in areas of Nebraska where adult control failures have occurred. Ongoing research on mechanisms of resistance, resistance inheritance patterns, and gene flow among populations will improve our ability to make predictions about the potential spread of resistance.
This paper will be presented on Monday.
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