Evidence of pyrethroid resistance evolution in western corn rootworm populations from the western U.S. Corn Belt

The western corn rootworm, Diabrotica virgifera virgifera LeConte, is among the most serious pests of maize in the United States. Since 2003, transgenic maize that produces insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) has been used to manage western corn rootworm by killing rootworm larvae, which feed on maize roots. In 2009, the first cases of field-evolved resistance to Bt maize were documented. These cases occurred in Iowa and involved maize that produced Bt toxin Cry3Bb1. Since then, resistance has expanded to include other geographies and additional Bt toxins, with some rootworm populations displaying resistance to all commercially available Bt traits. Factors that contributed to field-evolved resistance likely included non-recessive inheritance of resistance, minimal fitness costs of resistance and limited adult dispersal. Additionally, because maize is the primary agricultural crop on which rootworm larvae can survive, continuous maize cultivation, in particular continuous cultivation of Bt maize, appears to be another key factor facilitating resistance evolution. More diversified management of rootworm larvae, including rotating fields out of maize production and using soil-applied insecticide with non-Bt maize, in addition to planting refuges of non-Bt maize, should help to delay the evolution of resistance to current and future transgenic traits.

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Estimation of Cry3Bb1 resistance allele frequency in field populations of western corn rootworm using a genetic marker

G3 Genes|Genome|Genetics ◽

10.1093/g3journal/jkaa013 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alan Willse ◽

Lex Flagel ◽

Graham Head

Keyword(s):

Allele Frequency ◽

Western Corn Rootworm ◽

Allele Frequencies ◽

Chromosome 8 ◽

Corn Belt ◽

Corn Rootworm ◽

Resistance Allele ◽

Response To Selection ◽

The Us ◽

Causal Allele

Abstract Following the discovery of western corn rootworm (WCR; Diabrotica virgifera virgifera) populations resistant to the Bacillus thuringiensis (Bt) protein Cry3Bb1, resistance was genetically mapped to a single locus on WCR chromosome 8 and linked SNP markers were shown to correlate with the frequency of resistance among field-collected populations from the US Corn Belt. The purpose of this paper is to further investigate the relationship between one of these resistance-linked markers and the causal resistance locus. Using data from laboratory bioassays and field experiments, we show that one allele of the resistance-linked marker increased in frequency in response to selection, but was not perfectly linked to the causal resistance allele. By coupling the response to selection data with a genetic model of the linkage between the marker and the causal allele, we developed a model that allowed marker allele frequencies to be mapped to causal allele frequencies. We then used this model to estimate the resistance allele frequency distribution in the US Corn Belt based on collections from 40 populations. These estimates suggest that chromosome 8 Cry3Bb1 resistance allele frequency was generally low (<10%) for 65% of the landscape, though an estimated 13% of landscape has relatively high (>25%) resistance allele frequency.

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Resistance to Bt Corn by Western Corn Rootworm (Coleoptera: Chrysomelidae) in the U.S. Corn Belt

Journal of Integrated Pest Management ◽

10.1603/ipm13012 ◽

2013 ◽

Vol 4 (3) ◽

pp. 1-6 ◽

Cited By ~ 23

Author(s):

Eileen M. Cullen ◽

Michael E. Gray ◽

Aaron J. Gassmann ◽

Bruce E. Hibbard

Keyword(s):

Western Corn Rootworm ◽

Corn Belt ◽

Bt Corn ◽

Corn Rootworm ◽

The U.S

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Molecular characterization of western corn rootworm pyrethroid resistance

Pest Management Science ◽

10.1002/ps.6090 ◽

2020 ◽

Author(s):

Dariane Souza ◽

Blair D Siegfried ◽

Lance J Meinke ◽

Nicholas J Miller

Keyword(s):

Molecular Characterization ◽

Pyrethroid Resistance ◽

Western Corn Rootworm ◽

Corn Rootworm

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LEVEL OF LARVAL ATACK ON MAIZE ROOTS AS A CONSEQUENCE OF ARTIFICIAL INFESTATION WITH WESTERN CORN ROOTWORM EGGS

AGROFOR ◽

10.7251/agreng1701132t ◽

2018 ◽

Vol 2 (1) ◽

Author(s):

Snežana TANASKOVIĆ ◽

Branka POPOVIĆ ◽

Sonja GVOZDENAC ◽

Zsolt KARPÁTI ◽

Csengele BÓGNAR ◽

...

Keyword(s):

Ostrinia Nubilalis ◽

Control Plant ◽

Western Corn Rootworm ◽

Corn Belt ◽

Corn Rootworm ◽

Diabrotica Virgifera ◽

Maize Field ◽

Artificial Infestation ◽

Maize Roots ◽

Vojvodina Province

The Western corn rootworm (WCR), Diabrotica virgifera sp. virgifera(Col.,Chrysomelidae), is an oligophagous pest native in America. WCR is a maizepest present in all regions of the Corn Belt. It is an invasive species which was, inEurope, first identified in Serbia, in 1992, near the Belgrade airport. The presenceof this pest in maize field can cause losses and plant damages up to 100%. A fieldexperiment was carried out in Bečej, Vojvodina province (Serbia), during 2014 and2015. In the field, 96 plants (maize cultivar NS 640), arranged in 48 pairs wereselected. Each pair consisted of one plant artificially infested with WCR eggs (Dplant) and the control plant (C plant). In both years, the experiment in the field wasregularly inspected, once a week. During each observation, the presence of "gooseneck" symptoms was recorded, and the number of plants damaged by the mostimportant stem boring and leaf feeding insects (Ostrinia nubilalis, Helicoverpaarmigera, H. zeae, aphids, mites, cicadas, etc. ) was counted. Root damages wereassessed at the end of the experiment (September), according to Ostlie and Notzel(1987), on scale 1-6. Comparing the root damages on C and D plants, less rootdamages were established on C plants. Only six i. e. four D plants had healthy roots(rate 1) during 2014 and 2015, respectively. Between D plants in 2014, the mostdamaged were14 plants, with the rate 3 (least one root chewed to within 1½ inches(3. 8 cm) of the plant). In 2015, severe damages were registered on 18 plants,which were ranked as level 6 (with three or more nodes destroyed). Only two Cplants during vegetation 2014-2015were registered with damages with rate 5 (twonodes destroyed) and rate 6 (three or more nodes destroyed), respectively.

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