Characterization of Western Corn Rootworm (Coleoptera: Chrysomelidae) susceptibility to foliar insecticides in northeast Nebraska

Authors

Timothy B. Dang, University of Nebraska - LincolnFollow
Ana M. Vélez, University of Nebraska - LincolnFollow
Arnubio Valencia-Jiménez, Universidad de Caldas, Manizales, Colombia
Jordan Reinders, University of Nebraska-LincolnFollow
Emily E. Stricklin, University of Nebraska-Lincoln
Matthew W. Carroll, Bayer AG, CropScience Division, Chesterfield, MO
Clinton D. Pilcher, Corteva Agriscience, Johnston, IA
Jeffrey T. Krumm, Corteva Agriscience, Hastings, NE
Graham P. Head, Bayer AG, CropScience Division, Chesterfield, MO
Lance Meinke, University of Nebraska-LincolnFollow

Date of this Version

2023

Citation

Published in Journal of Economic Entomology, 116(3), 2023, 945–955

doi:10.1093/jee/toad067

Comments

Copyright © 2023 by the authors. Published by Oxford University Press on behalf of Entomological Society of America. Used by permission.

Abstract

Foliar-applied insecticides are commonly used for adult Western Corn Rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), control in Nebraska but little efficacy data is available. Anecdotal reports of reduced efficacy in areas of northeast Nebraska led to the conduct of this study. Objectives were to (i) evaluate the efficacy of commercial applications of commonly used formulated insecticides (bifenthrin, lambda-cyhalothrin, chlorpyrifos, or tank mixes) for WCR control in 7 northeast Nebraska counties during 2019 and 2020 and (ii) conduct adult WCR concentration-response vial bioassays with bifenthrin, chlorpyrifos, and dimethoate active ingredients on a subset of field populations. Whole plant counts (WPC) were used to measure WCR densities in insecticide-treated and untreated maize fields before and after insecticide application. Field control was excellent with organophosphate/pyrethroid tank mixes as proportional change in mean WPC of treated fields was significantly reduced (>0.90) versus untreated fields where little change in WPC occurred. The exception was one treated Boone County field where proportional reduction in WPC was ≤0.78. Bioassays revealed LC₅₀s and resistance ratios of most populations exposed to bifenthrin and dimethoate were not significantly different than the susceptible control. Most populations exhibited a low level of chlorpyrifos resistance when compared to the susceptible control. Field and lab data suggest the local onset of practical WCR field-evolved resistance to bifenthrin in Boone County and chlorpyrifos in Boone and Colfax counties. Results of this study will increase our understanding of WCR resistance evolution, serve as a comprehensive baseline for future research, and inform WCR management programs.