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ARS Home » Plains Area » Brookings, South Dakota » Integrated Cropping Systems Research » Research » Publications at this Location » Publication #355596

Research Project: Productive Cropping Systems Based on Ecological Principles of Pest Management

Location: Integrated Cropping Systems Research

Title: Spatial variation in western corn rootworm (Coleoptera: Chrysomelidae) susceptibility to Cry3 toxins in Nebraska

Author
item REINDERS, JORDAN - University Of Nebraska
item HITT, BRIANNA - University Of Nebraska
item STROUP, WALTER - University Of Nebraska
item French, Bryan
item MEINKE, LANCE - University Of Nebraska

Submitted to: PLoS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/14/2018
Publication Date: 11/29/2018
Citation: Reinders, J.D., Hitt, B.D., Stroup, W.W., French, B.W., Meinke, L.J. 2018. Spatial variation in western corn rootworm (Coleoptera: Chrysomelidae) susceptibility to Cry3 toxins in Nebraska. PLoS One. 13(11):e0208266. https://doi.org/10.1371/journal.pone.0208266.
DOI: https://doi.org/10.1371/journal.pone.0208266

Interpretive Summary: Repeated use of field corn expressing the Cry3 protein toxins in Nebraska has selected for resistance in western corn rootworm (WCR) populations. This study was conducted to characterize spatial variation in WCR susceptibility to Cry3Bb1 and mCry3A proteins in Keith and Buffalo counties, Nebraska, and determine the relationship between past management practices and current WCR susceptibility. We found that neighboring cornfields may support WCR populations with different levels of susceptibility, which indicates limited dispersal of resistance beetles. Analyzing the field history indicated years of trait use and associated selection pressure at the local level were the key drivers of WCR susceptibility to Cry3 traits in this system. Reviewing case histories from this study will inform development of optimal resistance management programs and increase understanding of plant-insect interactions when transgenic corn is deployed in the landscape. Our results also support current recommendations to slow or mitigate the evolution of resistance by using a multi-tactic approach to manage WCR populations in cornfields using an integrated pest management approach.

Technical Abstract: Repeated use of field corn (Zea mays L.) hybrids expressing the Cry3Bb1 and mCry3A traits in Nebraska has selected for field-evolved resistance in some western corn rootworm (WCR; Diabrotica virgifera virgifera LeConte) populations. Therefore, this study was conducted to characterize spatial variation in local WCR susceptibility to Cry3Bb1 and mCry3A traits in Keith and Buffalo counties, Nebraska, and determine the relationship between past management practices and current WCR susceptibility. Adult WCR populations were collected from sampling grids during 2015 and 2016 and single-plant larval bioassays conducted with F1 progeny documented significant variation in WCR susceptibility to Cry3Bb1 and mCry3A on different spatial scales in both sampling grids. At the local level, results revealed that neighboring cornfields may support WCR populations with very different susceptibility levels, indicating that gene flow of resistant alleles from high trait survival sites is not inundating large areas. A field history index, comprised of additive and weighted variables including past WCR management tactics and agronomic practices, was developed to quantify relative selection pressure in individual fields. The field history index-Cry3 trait survivorship relationship from year 1 data was highly predictive of year 2 Cry3 trait survivorship when year 2 field history indices were inserted into the year 1 base model. Sensitivity analyses indicated years of trait use and associated selection pressure at the local level were the key drivers of WCR susceptibility to Cry3 traits in this system. Retrospective case histories from this study will inform development of optimal resistance management programs and increase understanding of plant-insect interactions that may occur when transgenic corn is deployed in the landscape. Results from this study also support current recommendations to slow or mitigate the evolution of resistance by using a multi-tactic approach to manage WCR densities in individual fields within an integrated pest management framework.