Characterizing the relationship between western corn rootworm (Coleoptera: Chrysomelidae) larval survival on Cry3Bb1-expressing corn and larval development metrics

Authors: REINDERS, JORDAN - University Of Nebraska; WANGILA, DAVID - Bayer Cropscience; ROBINSON, EMILY - University Of Nebraska; FRENCH, B - Retired ARS Employee; MEINKE, LANCE - University Of Nebraska

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/2021
Publication Date: 7/29/2021
Citation: Reinders, J.D., Wangila, D.S., Robinson, E.A., French, B.W., Meinke, L.J. 2021. Characterizing the relationship between western corn rootworm (Coleoptera: Chrysomelidae) larval survival on Cry3Bb1-expressing corn and larval development metrics. Journal of Economic Entomology. 114(5):2096-2107. https://doi.org/10.1093/jee/toab151.
DOI: https://doi.org/10.1093/jee/toab151

Interpretive Summary: The western corn rootworm is a significant pest of field corn across the United States Corn Belt. Widespread adoption and continuous use of transgenic corn hybrids expressing the insecticidal Cry3Bb1 protein to manage the western corn rootworm has resulted in greater than expected injury to these corn hybrids in multiple areas of Nebraska. In these studies, we aimed to determine the level of rootworm resistance present in various Nebraska counties. Single-plant larval bioassays were conducted on larval western corn rootworm. The results confirmed a mosaic of susceptibility to Cry3Bb1 across Nebraska. Larval development metrics, including head capsule width and fresh weight, were measured to quantify the relationship between the level of resistance to Cry3Bb1 and larval developmental rate. Results indicate that as the level of resistance to Cry3Bb1 within field populations increases, mean head capsule width and larval fresh weight also increase. Regression and correlation analyses indicate a significant, positive relationship between Cry3Bb1 corrected survival and both larval development metrics. This increases our understanding of western corn rootworm population dynamics and age structure variability present in the transgenic landscape that is part of the complex interaction of factors that drives resistance evolution. This collective variability and complexity within the landscape reinforces the importance of making corn rootworm management decisions based on information collected at the local level.

Technical Abstract: The western corn rootworm, Diabrotica virgifera virgifera LeConte, is a significant pest of field corn, Zea mays L., across the United States Corn Belt. Widespread adoption and continuous use of corn hybrids expressing the Cry3Bb1 protein to manage the western corn rootworm has resulted in greater than expected injury to Cry3Bb1-expressing hybrids in multiple areas of Nebraska. Single-plant larval bioassays were conducted on larval western corn rootworm populations to determine the level of resistance present in various Nebraska counties. The results confirmed a mosaic of susceptibility to Cry3Bb1 across Nebraska. Larval development metrics, including head capsule width and fresh weight, were measured to quantify the relationship between the level of resistance to Cry3Bb1 and larval developmental rate. Results indicate that as the level of resistance to Cry3Bb1 within field populations increases, mean head capsule width and larval fresh weight also increase. Regression and correlation analyses indicate a significant, positive relationship between Cry3Bb1 corrected survival and both larval development metrics. This increases our understanding of western corn rootworm population dynamics and age structure variability present in the transgenic landscape that is part of the complex interaction of factors that drives resistance evolution. This collective variability and complexity within the landscape reinforces the importance of making corn rootworm management decisions based on information collected at the local level.