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ARS Home » Plains Area » Brookings, South Dakota » Integrated Cropping Systems Research » Research » Publications at this Location » Publication #385596
Research Project: Productive Cropping Systems Based on Ecological Principles of Pest Management

Location: Integrated Cropping Systems Research

Title: Evidence of western corn rootworm (Diabrotica virgifera virgifera LeConte) field-evolved resistance to Cry3Bb1 + Cry34/35Ab1 maize in Nebraska

Author
item REINDERS, JORDAN - University Of Nebraska
item REINDERS, EMILY - University Of Nebraska
item FRENCH, B - Retired ARS Employee
item MEINKE, LANCE - University Of Nebraska

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/3/2021
Publication Date: 12/7/2021
Citation: Reinders, J.E., Reinders, E.E., French, B.W., Meinke, L.J. 2021. Evidence of western corn rootworm (Diabrotica virgifera virgifera LeConte) field-evolved resistance to Cry3Bb1 + Cry34/35Ab1 maize in Nebraska. Pest Management Science. https://doi.org/10.1002/ps.6752.
DOI: https://doi.org/10.1002/ps.6752

Interpretive Summary: The western corn rootworm (WCR) is an insect pest of corn that is annually responsible for $1-2 billion USD in control costs and yield losses in the United States. Significant larval feeding injury can reduce plant growth by interfering with water and nutrient uptake, decrease plant stability, and reduce grain yield. Management programs for WCR have historically relied upon two main management strategies: 1) annual rotation between corn and a non-host crop, and 2) soil- or foliar-applied insecticides in corn grown for at least 2 successive years. The introduction of transgenic corn hybrids expressing rootworm-active insecticidal proteins derived from the soil bacterium Bacillus thuringiensis (Bt) Berliner provided growers with an additional management tactic to combat this pest in continuous maize. The high efficacy and convenience of transgenic corn facilitated widespread adoption by U.S. growers. Field-evolved resistance of Western corn rootworm to transgenic maize expressing the Cry3Bb1 protein derived from Bacillus thuringiensis (Bt) has been confirmed across the United States (U.S.) Corn Belt. The use of pyramided hybrids expressing Cry3Bb1 + Cry34/35Ab1 has increased in recent years to mitigate or slow existing WCR Bt resistance. In this study, we evaluated the susceptibility of Nebraska WCR populations to this rootworm-Bt pyramid in areas with a history of Cry3Bb1 and Cry34/35Ab1 cultivation. Most WCR populations were highly resistant to Cry3Bb1 and exhibited similar larval development when feeding on Cry3Bb1 and non-Bt corn, as indicated by head capsule width and fresh weight metrics. In contrast, most WCR populations exhibited a lower level of resistance to Cry3Bb1 + Cry34/35Ab1 corn and sublethal exposure to the rootworm-Bt pyramid resulted in more variable results in larval development compared to non-Bt corn. The present study documents a neighborhood WCR Cry3Bb1 resistance pattern and confirms the first cases of field-evolved resistance to Cry3Bb1 + Cry34/35Ab1 corn in Nebraska. Use of a multi-tactic integrated pest management approach is necessary in areas of continuous corn production to slow or mitigate resistance evolution to Bt corn.

Technical Abstract: BACKGROUND: Western corn rootworm (WCR; Diabrotica virgifera virgifera) field-evolved resistance to transgenic maize expressing the Cry3Bb1 protein derived from Bacillus thuringiensis (Bt) has been confirmed across the United States (U.S.) Corn Belt. Although the use of pyramided hybrids expressing Cry3Bb1 + Cry34/35Ab1 has increased in recent years to mitigate or slow existing WCR Bt resistance, the susceptibility of Nebraska WCR populations to this rootworm-Bt pyramid has not been assessed. The present study aimed to characterize the susceptibility of Nebraska WCR populations to Cry3Bb1 and Cry3Bb1 + Cry34/35Ab1 in areas with a history of Cry3Bb1 and Cry34/35Ab1 cultivation by conducting plant-based bioassays on F1 progeny of WCR populations collected in 2017 and 2018 from fields in northeast Nebraska. RESULTS: Most WCR populations were highly resistant to Cry3Bb1 and exhibited similar larval development when feeding on Cry3Bb1 and non-Bt maize, as indicated by head capsule width and fresh weight metrics. In contrast, most WCR populations exhibited a lower level of resistance to Cry3Bb1 + Cry34/35Ab1 maize and sublethal exposure to the rootworm-Bt pyramid resulted in more variable results in larval development compared to non-Bt maize. CONCLUSIONS: The present study documents a neighborhood WCR Cry3Bb1 resistance pattern and confirms the first cases of field-evolved resistance to Cry3Bb1 + Cry34/35Ab1 maize in Nebraska. Use of a multi-tactic integrated pest management approach is necessary in areas of continuous maize production to slow or mitigate resistance evolution to Bt maize.