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Sappington TW, Spencer JL. Movement Ecology of Adult Western Corn Rootworm: Implications for Management. INSECTS 2023; 14:922. [PMID: 38132596 PMCID: PMC10744206 DOI: 10.3390/insects14120922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/23/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023]
Abstract
Movement of adult western corn rootworm, Diabrotica virgifera virgifera LeConte, is of fundamental importance to this species' population dynamics, ecology, evolution, and interactions with its environment, including cultivated cornfields. Realistic parameterization of dispersal components of models is needed to predict rates of range expansion, development, and spread of resistance to control measures and improve pest and resistance management strategies. However, a coherent understanding of western corn rootworm movement ecology has remained elusive because of conflicting evidence for both short- and long-distance lifetime dispersal, a type of dilemma observed in many species called Reid's paradox. Attempts to resolve this paradox using population genetic strategies to estimate rates of gene flow over space likewise imply greater dispersal distances than direct observations of short-range movement suggest, a dilemma called Slatkin's paradox. Based on the wide-array of available evidence, we present a conceptual model of adult western corn rootworm movement ecology under the premise it is a partially migratory species. We propose that rootworm populations consist of two behavioral phenotypes, resident and migrant. Both engage in local, appetitive flights, but only the migrant phenotype also makes non-appetitive migratory flights, resulting in observed patterns of bimodal dispersal distances and resolution of Reid's and Slatkin's paradoxes.
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Affiliation(s)
- Thomas W. Sappington
- Corn Insects and Crop Genetics Research Unit, United States Department of Agriculture, Agricultural Research Service, Ames, IA 50011, USA
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Joseph L. Spencer
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois, Champaign, IL 61820, USA
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Oyediran I, Rice ME, Conville J, Boudreau E, Morsello S, Burd T. Bt corn hybrids expressing mCry3A and eCry3.1Ab Proteins protect corn roots against western corn rootworm injury. PEST MANAGEMENT SCIENCE 2023; 79:4839-4846. [PMID: 37489843 DOI: 10.1002/ps.7680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 07/26/2023]
Abstract
BACKGROUND The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is one of the most serious pests of corn (Zea mays L.) In 2017 and 2018, studies were conducted in fields with and without known unexpected root injury to Cry3Bb1, to determine root protection by Bt corn hybrids expressing both mCry3A and eCry3.1Ab insecticidal crystal proteins, and hybrids expressing either mCry3A or eCry3.1Ab only against the WCR root injury. Node injury was evaluated using the Iowa State University 0-3 node-injury scale (NIS), and the consistency of root protection was also determined. RESULTS In 2017, with medium to high larval feeding pressure, the Bt corn hybrids expressing both mCry3A and eCry3.1Ab in the breeding stack, molecular stack, and Bt corn hybrid expressing eCry3.1Ab only, sustained low node injury compared with Bt corn hybrid expressing mCry3A only, and the non-Bt corn. In 2018, with low larval feeding pressure in most of the locations, node injury was not different for the Bt and Non-Bt corn hybrids. Across all locations in both years, the Bt corn hybrids expressing both mCry3A and eCry3.1Ab provided better and consistent node injury protection. CONCLUSION Bt corn hybrids expressing both mCry3A and eCry3.1Ab proteins provided better root protection and consistency than the Bt corn hybrid expressing mCry3A only, and non-Bt. Therefore, stacking of Bt traits will be the best option for managing insect resistance. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Isaac Oyediran
- Syngenta Crop Protection LLC, Research Triangle Park, North Carolina, USA
| | - Marlin E Rice
- Syngenta Crop Protection LLC, Research Triangle Park, North Carolina, USA
| | - Jared Conville
- Syngenta Crop Protection LLC, Research Triangle Park, North Carolina, USA
| | - Eric Boudreau
- Syngenta Crop Protection LLC, Research Triangle Park, North Carolina, USA
| | | | - Tony Burd
- Syngenta Crop Protection LLC, Greensboro, North Carolina, USA
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Gassmann AJ, Reisig DD. Management of Insect Pests with Bt Crops in the United States. ANNUAL REVIEW OF ENTOMOLOGY 2023; 68:31-49. [PMID: 36170641 DOI: 10.1146/annurev-ento-120220-105502] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Genetically engineered corn and cotton that produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) have been used to manage insect pests in the United States and elsewhere. In some cases, this has led to regional suppression of pest populations and pest eradication within the United States, and these outcomes were associated with reductions in conventional insecticides and increased profits for farmers. In other instances, pests evolved resistance to multiple Bt traits, compromising the capacity of Bt crops to manage pests and leading to increased feeding injury to crops in the field. Several aspects of pest biology and pest-crop interactions were associated with cases where pests remained susceptible versus instances where pests evolved resistance. The viability of future transgenic traits can be improved by learning from these past outcomes. In particular, efforts should be made to delay resistance by increasing the prevalence of refuges and using integrated pest management.
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Affiliation(s)
- Aaron J Gassmann
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, Iowa, USA;
| | - Dominic D Reisig
- Department of Entomology and Plant Pathology, North Carolina State University, Plymouth, North Carolina, USA
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Wang X, Shi T, Tang P, Liu S, Hou B, Jiang D, Lu J, Yang Y, Carrière Y, Wu Y. Baseline susceptibility of Helicoverpa armigera, Plutella xylostella, and Spodoptera frugiperda to the meta-diamide insecticide broflanilide. INSECT SCIENCE 2022. [PMID: 36326623 DOI: 10.1111/1744-7917.13142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/13/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
Broflanilide is a novel meta-diamide insecticide that acts as a γ-aminobutyric acid-gated chloride channel allosteric modulator. With its unique mode of action, broflanilide has no known cross-resistance with existing insecticides and is expected to be an effective tool for the management of insecticide resistance. Establishing the baseline susceptibility to this insecticide is an essential step for developing and implementing effective resistance management strategies. Here we evaluated the baseline susceptibility to broflanilide for 3 cosmopolitan lepidopteran pest species, Helicoverpa armigera, Plutella xylostella, and Spodoptera frugiperda. Broflanilide exhibited high activity against populations sampled in the major distribution range of these pests in China, with median lethal concentrations (LC50 ) ranging between 0.209 and 0.684, 0.076 and 0.336, and 0.075 and 0.219 mg/L for H. armigera, P. xylostella, and S. frugiperda, respectively. Among-population variability in susceptibility to broflanilide was moderate for H. armigera (3.3-fold), P. xylostella (4.4-fold), and S. frugiperda (2.9-fold). The recommended diagnostic concentrations for H. armigera, P. xylostella, and S. frugiperda were 8, 4, and 2 mg/L, respectively. Little or no cross-resistance to broflanilide was detected in 3 diamide-resistant strains of P. xylostella and 1 spinosyns-resistant strain of S. frugiperda. Our results provide critical information for the development of effective resistance management programs to sustain efficacy of broflanilide against these key lepidopteran pests.
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Affiliation(s)
- Xingliang Wang
- Key Laboratory of Integrated Pest Management on Crops in East China (MARA), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Tailong Shi
- Key Laboratory of Integrated Pest Management on Crops in East China (MARA), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Ping Tang
- Key Laboratory of Integrated Pest Management on Crops in East China (MARA), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Shengnan Liu
- Key Laboratory of Integrated Pest Management on Crops in East China (MARA), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Bofeng Hou
- Key Laboratory of Integrated Pest Management on Crops in East China (MARA), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Dong Jiang
- Key Laboratory of Integrated Pest Management on Crops in East China (MARA), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Jingde Lu
- Key Laboratory of Integrated Pest Management on Crops in East China (MARA), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Yihua Yang
- Key Laboratory of Integrated Pest Management on Crops in East China (MARA), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Yves Carrière
- Department of Entomology, the University of Arizona, Tucson, AZ, USA
| | - Yidong Wu
- Key Laboratory of Integrated Pest Management on Crops in East China (MARA), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
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Reinders JD, Reinders EE, Robinson EA, French BW, Meinke LJ. Evidence of western corn rootworm (Diabrotica virgifera virgifera LeConte) field-evolved resistance to Cry3Bb1 + Cry34/35Ab1 maize in Nebraska. PEST MANAGEMENT SCIENCE 2022; 78:1356-1366. [PMID: 34873825 DOI: 10.1002/ps.6752] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 12/02/2021] [Accepted: 12/07/2021] [Indexed: 06/13/2023]
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 Corn Belt. Although use of pyramided hybrids expressing Cry3Bb1 + Cry34/35Ab1 has increased in recent years to mitigate existing WCR Bt resistance, susceptibility of Nebraska WCR populations to this rootworm-Bt pyramid has not been assessed. Plant-based bioassays were used to characterize the susceptibility of WCR populations to Cry3Bb1 and Cry3Bb1 + Cry34/35Ab1 maize. Populations were collected from areas of northeastern Nebraska with a history of planting Bt maize that expressed Cry3Bb1 and Cry34/35Ab1. RESULTS Significant differences in mean corrected survival among populations within Bt hybrids indicated a mosaic of WCR susceptibility to Cry3Bb1 + Cry34/35Ab1 and Cry3Bb1 maize occurred in the landscape. All field populations exhibited some level of resistance to one or both Bt hybrids when compared to susceptible laboratory control populations in bioassays. Most WCR populations exhibited incomplete resistance to Cry3Bb1 + Cry34/35Ab1 maize (92%) and complete resistance to Cry3Bb1 maize (79%). CONCLUSION The present study confirms the first cases of field-evolved resistance to Cry3Bb1 + Cry34/35Ab1 maize in Nebraska and documents a landscape-wide WCR Cry3Bb1 resistance pattern in areas characterized by long-term continuous maize production and associated planting of Cry3Bb1 hybrids. Use of a multi-tactic integrated pest management approach is needed in areas of continuous maize production to slow or mitigate resistance evolution to Bt maize. © 2021 Society of Chemical Industry.
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Affiliation(s)
| | - Emily E Reinders
- Department of Entomology, University of Nebraska, Lincoln, NE, USA
| | - Emily A Robinson
- Department of Statistics, University of Nebraska, Lincoln, NE, USA
| | - Bryan W French
- United States Department of Agriculture, Agricultural Research Service, North Central Agricultural Research Laboratory, Brookings, SD, USA
| | - Lance J Meinke
- Department of Entomology, University of Nebraska, Lincoln, NE, USA
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St Clair CR, Gassmann AJ. Linking land use patterns and pest outbreaks in Bt maize. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02295. [PMID: 33428798 DOI: 10.1002/eap.2295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 08/05/2020] [Accepted: 10/05/2020] [Indexed: 06/12/2023]
Abstract
Western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a major pest of maize in the United States and is an invasive pest in Europe. Maize is the only agricultural crop on which western corn rootworm larvae can survive and this insect requires two consecutive years of maize cultivation to complete its life cycle. Transgenic maize producing insecticidal proteins derived from the bacterium Bacillus thuringiensis (Bt) is often used to manage rootworm populations. The first Bt trait, Cry3Bb1, was introduced in 2003, but larval resistance to this toxin appeared in northeastern Iowa in 2009. Rootworm management occurs on a field-by-field basis, but adult rootworm may disperse among fields. It is known that growing consecutive years of Cry3Bb1 maize within a field can lead to resistance, but the relationship of the surrounding landscape to the development of resistance is unknown. Using geospatial tools and publicly available land-use data, we examined circular areas (buffers) surrounding fields that had previously experienced high levels of rootworm injury to Cry3Bb1 maize and rootworm resistance to Cry3Bb1 maize (problem fields). We calculated the proportion of area inside each buffer planted to maize continuously for 1-9 yr, and compared these values to those for randomly selected control points throughout the state. We also calculated the proportion of the state planted to maize for at least three consecutive years for 2003 through 2018, and its relationship with the annual value of maize. We found that areas surrounding problem fields had significantly more continuous maize compared to controls, with the most continuous maize within 1.6 km of problem fields. We also found that the cultivation of continuous maize in Iowa increased significantly between 2003 and 2018, and this was correlated with average annual price of maize. We hypothesize a scenario in which continuous cultivation of Cry3Bb1 maize in local landscapes, driven in part by the increased value of maize, facilitated selection for Cry3Bb1 resistance. These results suggest that land use in areas surrounding problem fields affect the rate of resistance evolution and approaches for resistance management can be enhanced by taking a landscape-level perspective.
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Affiliation(s)
- Coy R St Clair
- Department of Entomology, Iowa State University, 2310 Pammel Drive, 339 Science Hall II, Ames, Iowa, 50011, USA
| | - Aaron J Gassmann
- Department of Entomology, Iowa State University, 2310 Pammel Drive, 339 Science Hall II, Ames, Iowa, 50011, USA
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Resistance to Bt Maize by Western Corn Rootworm: Effects of Pest Biology, the Pest-Crop Interaction and the Agricultural Landscape on Resistance. INSECTS 2021; 12:insects12020136. [PMID: 33562469 PMCID: PMC7915852 DOI: 10.3390/insects12020136] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/30/2022]
Abstract
Simple Summary Since the 1990s, an important innovation in the management of agricultural pest insects has been the commercial cultivation of genetically engineered crops that produce insecticidal toxins, which in turn act to protect plants from feeding injury by insects. To date, these transgenic crops, which include cotton, maize and soybean, have produced insecticidal proteins derived from the bacterium Bacillus thuringiensis (Bt). Benefits associated with planting of Bt crops include reduced feeding injury from pest insects, decreased yield losses from pests and less harm to the environment. However, the evolution of Bt resistance by insect pests can diminish these benefits. One serious insect pest currently managed with Bt maize is the western corn rootworm. The larval stage of this insect feeds on maize roots and can substantially reduce yield. In some parts of the US Corn Belt, western corn rootworm rapidly adapted to Bt maize, and currently, some populations show resistance to all commercially available Bt traits. This review summarizes the time course of resistance development in the field, key factors contributing to resistance evolution, and steps that biotechnology companies, farmers and regulatory agencies can take to delay additional cases of pest resistance to current and future transgenic technologies. Abstract 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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St. Clair CR, Head GP, Gassmann AJ. Comparing Populations of Western Corn Rootworm (Coleoptera: Chrysomelidae) in Regions With and Without a History of Injury to Cry3 Corn. JOURNAL OF ECONOMIC ENTOMOLOGY 2020; 113:1839-1849. [PMID: 32449512 PMCID: PMC7425785 DOI: 10.1093/jee/toaa106] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Indexed: 06/11/2023]
Abstract
Transgenic corn expressing insecticidal proteins derived from the bacterium Bacillus thuringiensis (Bt) is an important pest management tool. Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a key pest of corn in the midwestern United States that has developed field-evolved resistance to all available Bt traits. The first Bt trait to be commercialized for management of rootworm was Cry3Bb1 in 2003, and field-evolved resistance appeared in 2009. In this study, we examined fields in counties where greater-than-expected injury to Cry3 (Cry3Bb1 or mCry3A) corn roots (>1 node) had previously been reported (problem counties) and counties where injury had not been reported (non-problem counties). Four to eight fields were sampled per county in 2015, 2016, and 2017 to quantify rootworm abundance, root injury, Cry3Bb1resistance, and rootworm management strategies. Rootworm abundance, root injury, and resistance to Cry3Bb1 did not differ between county types. Management tactics differed between county types, with problem counties growing more corn, using more soil insecticide, and growing more Cry34/35Ab1 corn. Additionally, a comparison of root injury to Bt and non-Bt corn within fields indicated that farmers derived an economic benefit from planting Bt corn to manage corn rootworm. Our results suggest that rootworm populations are similar between problem and non-problem counties in Iowa due to similar levels of selection pressure on Cry3 corn, but problem county fields have applied more management tactics due to previous rootworm issues in the area.
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Affiliation(s)
| | - Graham P Head
- Bayer Crop Science, Resistance Management, Chesterfield, MO
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St. Clair CR, Head GP, Gassmann AJ. Western corn rootworm abundance, injury to corn, and resistance to Cry3Bb1 in the local landscape of previous problem fields. PLoS One 2020; 15:e0237094. [PMID: 32735582 PMCID: PMC7394452 DOI: 10.1371/journal.pone.0237094] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 07/20/2020] [Indexed: 11/20/2022] Open
Abstract
Western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a major pest of corn in the United States. Transgenic corn expressing insecticidal proteins derived from the bacterium Bacillus thuringiensis (Bt) is an important tool used to manage rootworm populations. However, field-evolved resistance to Bt threatens this technology. In areas where resistance is present, resistant individuals may travel from one field to a neighboring field, spreading resistance alleles. An important question that remains to be answered is the extent to which greater-than-expected root injury (i.e., >1 node of injury) to Cry3Bb1 corn from western corn rootworm is associated with rootworm abundance, root injury, and levels of resistance in neighboring fields. To address this question, fields with a history of greater-than-expected injury to Cry3Bb1 corn (focal fields) and surrounding fields (< 2.2 km from focal fields) were examined to quantify rootworm abundance, root injury, and resistance to Cry3Bb1 corn. Additionally, use of Bt corn and soil insecticide use for the previous six years were quantified for each field. Resistance to Cry3Bb1 was present in all fields assayed, even though focal fields had grown more Cry3 corn and less non-Bt corn than surrounding fields. This finding implies that some movement of resistance alleles had occurred between focal fields and surrounding fields. Overall, our data suggest that resistance to Cry3Bb1 in the landscape has been influenced by both local rootworm movement and field-level management tactics.
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Affiliation(s)
- Coy R. St. Clair
- Department of Entomology, Iowa State University, Ames, IA, United States of America
- * E-mail:
| | - Graham P. Head
- Bayer Crop Science, Resistance Management, Chesterfield, MO, United States of America
| | - Aaron J. Gassmann
- Department of Entomology, Iowa State University, Ames, IA, United States of America
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Gassmann AJ, Shrestha RB, Kropf AL, St Clair CR, Brenizer BD. Field-evolved resistance by western corn rootworm to Cry34/35Ab1 and other Bacillus thuringiensis traits in transgenic maize. PEST MANAGEMENT SCIENCE 2020; 76:268-276. [PMID: 31207042 DOI: 10.1002/ps.5510] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Transgenic crops producing insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) are widely planted to manage agricultural insect pests. However, widespread adoption of Bt crops has led to the evolution of Bt resistance. The western corn rootworm, Diabrotica virgifera virgifera, is among the most serious pests of maize in the midwestern United States and is currently managed with Bt maize. To date, there is evidence of field-evolved resistance to all Bt toxins used to manage this pest. While western corn rootworm resistance to Cry3Bb1, and the closely related mCry3A and eCry3.1Ab traits, is widely distributed within the Midwest, fewer cases of Cry34/35Ab1 resistance have been observed, and planting of Cry34/35Ab1 maize is one of the methods used to manage Cry3-resistant rootworm. RESULTS We found that fields with high levels of root injury to Cry34/35Ab1 maize by western corn rootworm were associated with Cry34/35Ab1-resistant western corn rootworm. Additionally, a population not associated with high levels of root injury was found to be resistant to Cry34/35Ab1. In all cases, populations that were resistant to Cry34/35Ab1 also were resistant to Cry3 traits. CONCLUSIONS Western corn rootworm resistance to Cry34/35Ab1 has continued to persist in the agricultural landscape and has likely increased. The presence of rootworm populations with resistance to all available Bt traits threatens the utility of current and future transgenic technologies to manage this pest. Decreased reliance on Cry34/35Ab1 and better use of integrated pest management will be essential to preserve Bt susceptibility in western corn rootworm. © 2019 Society of Chemical Industry.
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Affiliation(s)
| | - Ram B Shrestha
- Department of Entomology, Iowa State University, Ames, IA, USA
| | - Abigail L Kropf
- Department of Entomology, Iowa State University, Ames, IA, USA
| | - Coy R St Clair
- Department of Entomology, Iowa State University, Ames, IA, USA
| | - Ben D Brenizer
- Department of Entomology, Iowa State University, Ames, IA, USA
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Shrestha RB, Gassmann AJ. Field and Laboratory Studies of Resistance to Bt Corn by Western Corn Rootworm (Coleoptera: Chrysomelidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2019; 112:2324-2334. [PMID: 31165163 DOI: 10.1093/jee/toz151] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Indexed: 06/09/2023]
Abstract
Western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), has developed resistance to transgenic corn that produces the insecticidal toxin Cry3Bb1 derived from the bacterium Bacillus thuringiensis (Bacillales: Bacillaceae) (Bt), with cross-resistance extending to corn with Bt toxins mCry3A and eCry3.1Ab. Additionally, some populations of western corn rootworm have evolved resistance to Cry34/35Ab1 corn. We conducted a 2-yr field and laboratory study that included three field locations: 1) Bt-susceptible population, 2) field with a recent history of Cry3Bb1 resistance, and 3) field with a long-term history of Cry3Bb1 resistance. The population with recently evolved Cry3Bb1 resistance showed resistance to Cry3Bb1 corn in both laboratory bioassays and field evaluations; by contrast, the population with a long-term history of Cry3Bb1 resistance showed resistance, in both laboratory and field experiments to Cry3Bb1 corn and corn with a pyramid of mCry3A plus eCry3.1Ab corn. Field-based evaluations also showed that the field population with a long-term history of Cry3Bb1 resistance imposed higher root injury to Cry3Bb1 corn and the pyramid of mCry3A plus eCry3.1Ab compared with the susceptible control. The results of this study are discussed in the context of developing strategies to manage western corn rootworm in areas where populations have evolved resistance to Cry3Bb1 corn.
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Calles-Torrez V, Knodel JJ, Boetel MA, French BW, Fuller BW, Ransom JK. Field-Evolved Resistance of Northern and Western Corn Rootworm (Coleoptera: Chrysomelidae) Populations to Corn Hybrids Expressing Single and Pyramided Cry3Bb1 and Cry34/35Ab1 Bt Proteins in North Dakota. JOURNAL OF ECONOMIC ENTOMOLOGY 2019; 112:1875-1886. [PMID: 31114868 DOI: 10.1093/jee/toz111] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Indexed: 06/09/2023]
Abstract
Northern, Diabrotica barberi Smith & Lawrence, and western, D. virgifera virgifera LeConte, corn rootworms (Coleoptera: Chrysomelidae) are major economic pests of corn, Zea mays L., in North America. Corn hybrids expressing Bacillus thuringiensis Berliner (Bt) toxins are commonly used by growers to manage these pests. Several cases of field-evolved resistance to insecticidal proteins expressed by Bt corn hybrids have been documented in many corn-producing areas of North America, but only for D. v. virgifera. In 2016, beetles of both species were collected from five eastern North Dakota corn fields and reared in a growth chamber. In 2017, larvae reared from those populations were subjected to single-plant bioassays to screen for potential resistance to Cry3Bb1, Cry34/35Ab1, and pyramided Cry3Bb1 + Cry34/35Ab1 Bt toxins. Our results provide the first documented report of field-evolved resistance in D. barberi to corn hybrids expressing Cry3Bb1 (Arthur problem population) and Cry34/35Ab1 (Arthur and Page problem populations, and the Ransom and Sargent populations) proteins in North America. Resistance to Cry3Bb1 was also observed in the Ransom population of D. v. virgifera. Increased larval survival on the pyramided Cry3Bb1 + Cry34/35Ab1 hybrid was observed in both species. No cross-resistance was evident between Cry3Bb1 and Cry34/35Ab1 in any of the D. barberi populations tested. Our experiments identified field-evolved resistance to Bt toxins in some North Dakota populations of D. barberi and D. v. virgifera. Thus, more effective control tools and improved resistance management strategies are needed to prolong the durability of this technology for managing these important pests.
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Affiliation(s)
| | - Janet J Knodel
- Department of Plant Pathology, North Dakota State University, Dept., Fargo, ND
| | - Mark A Boetel
- Department of Entomology, North Dakota State University, Dept., Fargo, ND
| | - B Wade French
- USDA-ARS North Central Agricultural Research Laboratory, Brookings, SD
| | - Billy W Fuller
- Department of Agronomy, Horticulture, and Plant Science, South Dakota State University, Brookings, SD
| | - Joel K Ransom
- Department of Plant Sciences, North Dakota State University, Fargo, ND
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13
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Fishilevich E, Bowling AJ, Frey MLF, Wang PH, Lo W, Rangasamy M, Worden SE, Pence HE, Gandra P, Whitlock SL, Schulenberg G, Knorr E, Tenbusch L, Lutz JR, Novak S, Hamm RL, Schnelle KD, Vilcinskas A, Narva KE. RNAi targeting of rootworm Troponin I transcripts confers root protection in maize. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 104:20-29. [PMID: 30243801 DOI: 10.1016/j.ibmb.2018.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/08/2018] [Accepted: 09/16/2018] [Indexed: 06/08/2023]
Abstract
Western corn rootworm, Diabrotica virgifera virgifera, is the major agronomically important pest of maize in the US Corn Belt. To augment the repertoire of the available dsRNA-based traits that control rootworm, we explored a potentially haplolethal gene target, wings up A (wupA), which encodes Troponin I. Troponin I, a component of the Troponin-Tropomyosin complex, is an inhibitory protein involved in muscle contraction. In situ hybridization showed that feeding on wupA-targeted dsRNAs caused systemic transcript knockdown in D. v. virgifera larvae. The knockdown of wupA transcript, and by extension Troponin I protein, led to deterioration of the striated banding pattern in larval body muscle and decreased muscle integrity. Additionally, the loss of function of the circular muscles surrounding the alimentary system led to significant accumulation of food material in the hind gut, which is consistent with a loss of peristaltic motion of the alimentary canal. In this study, we demonstrate that wupA dsRNA is lethal in D. v. virgifera larvae when fed via artificial diet, with growth inhibition of up to 50% within two days of application. Further, wupA hairpins can be stably expressed and detected in maize. Maize expressing wupA hairpins exhibit robust root protection in greenhouse bioassays, with several maize transgene integration events showing root protection equivalent to commercial insecticidal protein-expressing maize.
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Affiliation(s)
- Elane Fishilevich
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States; University of Nebraska - Lincoln, Department of Entomology, Entomology Hall, Lincoln, NE, 68583-0816, United States.
| | - Andrew J Bowling
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Meghan L F Frey
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Po-Hao Wang
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Wendy Lo
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Murugesan Rangasamy
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Sarah E Worden
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Heather E Pence
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Premchand Gandra
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Shannon L Whitlock
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Greg Schulenberg
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Eileen Knorr
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Department of Bioresources, Winchester Str. 2, 35394, Giessen, Germany
| | - Linda Tenbusch
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Department of Bioresources, Winchester Str. 2, 35394, Giessen, Germany
| | - Jamie R Lutz
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Stephen Novak
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Ronda L Hamm
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Karl D Schnelle
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States
| | - Andreas Vilcinskas
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Department of Bioresources, Winchester Str. 2, 35394, Giessen, Germany
| | - Kenneth E Narva
- Corteva Agriscience™, Agriculture Division of DowDuPont™, 9330 Zionsville Road, Indianapolis, IN, 46268, United States.
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Wen Z, Chen JS. A Simple and Sensitive Plant-Based Western Corn Rootworm Bioassay Method for Resistance Determination and Event Selection. JOURNAL OF ECONOMIC ENTOMOLOGY 2018; 111:1842-1850. [PMID: 29846650 DOI: 10.1093/jee/toy141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Indexed: 06/08/2023]
Abstract
We report here a simple and sensitive plant-based western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), bioassay method that allows for examination of multiple parameters for both plants and insects in a single experimental setup within a short duration. For plants, injury to roots can be visually examined, fresh root weight can be measured, and expression of trait protein in plant roots can be analyzed. For insects, in addition to survival, larval growth and development can be evaluated in several aspects including body weight gain, body length, and head capsule width. We demonstrated using the method that eCry3.1Ab-expressing 5307 corn was very effective against western corn rootworm by eliciting high mortality and significantly inhibiting larval growth and development. We also validated that the method allowed determination of resistance in an eCry3.1Ab-resistant western corn rootworm strain. While data presented in this paper demonstrate the usefulness of the method for selection of events of protein traits and for determination of resistance in laboratory populations, we envision that the method can be applied in much broader applications.
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Affiliation(s)
- Zhimou Wen
- Syngenta Crop Protection, LLC, Davis Drive, Research Triangle Park, NC
| | - Jeng Shong Chen
- Syngenta Crop Protection, LLC, Davis Drive, Research Triangle Park, NC
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15
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Calles-Torrez V, Knodel JJ, Boetel MA, Doetkott CD, Podliska KK, Ransom JK, Beauzay P, French BW, Fuller BW. Transgenic Bt Corn, Soil Insecticide, and Insecticidal Seed Treatment Effects on Corn Rootworm (Coleoptera: Chrysomelidae) Beetle Emergence, Larval Feeding Injury, and Corn Yield in North Dakota. JOURNAL OF ECONOMIC ENTOMOLOGY 2018; 111:348-360. [PMID: 29186516 DOI: 10.1093/jee/tox297] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Indexed: 05/24/2023]
Abstract
Northern, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae), and western, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), corn rootworms are economic pests of corn, Zea mays L. in North America. We measured the impacts of corn hybrids incorporated with Cry3Bb1, Cry34/35Ab1, and pyramided (Cry3Bb1 + Cry34/35Ab1) Bacillus thuringiensis Berliner (Bt) proteins, tefluthrin soil insecticide, and clothianidin insecticidal seed treatment on beetle emergence, larval feeding injury, and corn yield at five locations from 2013 to 2015 in eastern North Dakota. In most cases, emergence was significantly lower in Bt-protected corn than in non-Bt corn hybrids. Exceptions included Wyndmere, ND (2013), where D. barberi emergence from Cry34/35Ab1 plots was not different from that in the non-Bt hybrid, and Arthur, ND (2013), where D. v. virgifera emergence from Cry3Bb1 plots did not differ from that in the non-Bt hybrid. Bt hybrids generally produced increased grain yield compared with non-Bt corn where rootworm densities were high, and larval root-feeding injury was consistently lower in Bt-protected plots than in non-Bt corn. The lowest overall feeding injury and emergence levels occurred in plots planted with the Cry3Bb1 + Cry34/35Ab1 hybrid. Time to 50% cumulative emergence of both species was 5-7 d later in Bt-protected than in non-Bt hybrids. Tefluthrin and clothianidin were mostly inconsequential in relation to beetle emergence and larval root injury. Our findings could suggest that some North Dakota populations could be in early stages of increased tolerance to some Bt toxins; however, Bt corn hybrids currently provide effective protection against rootworm injury in eastern North Dakota.
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Affiliation(s)
| | - Janet J Knodel
- Department of Plant Pathology, North Dakota State University, Dept. 7660, Fargo, ND
| | - Mark A Boetel
- Department of Entomology, North Dakota State University, Dept. 7650, Fargo, ND
| | - Curt D Doetkott
- Statistical Consulting Services, North Dakota State University, Dept. 4500, Fargo, ND
| | - Kellie K Podliska
- Department of Plant Sciences, North Dakota State University, Dept. 7670, Fargo, ND
| | - Joel K Ransom
- Department of Plant Sciences, North Dakota State University, Dept. 7670, Fargo, ND
| | - Patrick Beauzay
- Department of Plant Pathology, North Dakota State University, Dept. 7660, Fargo, ND
| | - B Wade French
- North Central Agricultural Research Laboratory, Brookings, SD
| | - Billy W Fuller
- Department of Agronomy, Horticulture, and Plant Science, South Dakota State University, Brookings, SD
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16
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Paolino AR, Gassmann AJ. Assessment of Inheritance and Fitness Costs Associated with Field-Evolved Resistance to Cry3Bb1 Maize by Western Corn Rootworm. Toxins (Basel) 2017; 9:E159. [PMID: 28492498 PMCID: PMC5450707 DOI: 10.3390/toxins9050159] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/04/2017] [Accepted: 05/05/2017] [Indexed: 01/12/2023] Open
Abstract
The western corn rootworm, Diabrotica virgifera virgifera LeConte, is among the most serious insect pests of maize in North America. One strategy used to manage this pest is transgenic maize that produces one or more crystalline (Cry) toxins derived from the bacterium Bacillus thuringiensis (Bt). To delay Bt resistance by insect pests, refuges of non-Bt maize are grown in conjunction with Bt maize. Two factors influencing the success of the refuge strategy to delay resistance are the inheritance of resistance and fitness costs, with greater delays in resistance expected when inheritance of resistance is recessive and fitness costs are present. We measured inheritance and fitness costs of resistance for two strains of western corn rootworm with field-evolved resistance to Cry3Bb1 maize. Plant-based and diet-based bioassays revealed that the inheritance of resistance was non-recessive. In a greenhouse experiment, in which larvae were reared on whole maize plants in field soil, no fitness costs of resistance were detected. In a laboratory experiment, in which larvae experienced intraspecific and interspecific competition for food, a fitness cost of delayed larval development was identified, however, no other fitness costs were found. These findings of non-recessive inheritance of resistance and minimal fitness costs, highlight the potential for the rapid evolution of resistance to Cry3Bb1 maize by western corn rootworm, and may help to improve resistance management strategies for this pest.
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Affiliation(s)
- Aubrey R Paolino
- Department of Entomology, Iowa State University, Ames, IA 50011, USA.
| | - Aaron J Gassmann
- Department of Entomology, Iowa State University, Ames, IA 50011, USA.
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17
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Wangila DS, Valencia J A, Wang H, Siegfried BD, Meinke LJ. Influence of calcareous soil on Cry3Bb1 expression and efficacy in the field. Transgenic Res 2017; 26:419-428. [PMID: 28326506 DOI: 10.1007/s11248-017-0014-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Accepted: 03/14/2017] [Indexed: 11/26/2022]
Abstract
Greater than expected injury by western corn rootworm (WCR) (Diabrotica virgifera virgifera LeConte) to Cry3Bb1 expressing maize hybrids (Zea mays L.) has been reported in southwestern Nebraska. Affected areas of some fields are often associated with high pH calcareous soils where maize growth is poor and iron chlorosis is common. As part of a comprehensive study to understand potential causes of unexpected injury, experiments were conducted during 2013 and 2014 to ascertain whether the calcareous soil conditions and associated poor maize growth negatively affect the expression of Cry3Bb1. Quantitative determination of Cry3Bb1 protein expression levels in root tissues was carried out on plants at V5-V6 growth stage using the enzyme-linked immunosorbent assay. Cry3Bb1 and non-Bt near isoline maize hybrids were artificially infested with Cry3Bb1-susceptible WCR eggs to measure survival and efficacy of Cry3Bb1 maize in calcareous and non-calcareous soils. Results showed that there was not a significant difference in expression of Cry3Bb1 protein between plants from calcareous and non-calcareous soils (18.9-21.2 µg/g fresh weight). Western corn rootworm survival was about sevenfold greater from the non-Bt isoline than Cry3Bb1 maize indicating that Cry3Bb1 performed as expected when infested with a Cry3Bb1 susceptible rootworm population. When survival from calcareous and non-calcareous soils was compared, no significant differences were observed in each soil. A significant positive correlation between soil pH and expression of Cry3Bb1 protein in roots was detected from samples collected in 2014 but not in 2013. No such correlation was found between soil pH and survival of WCR. Results suggest that Cry3Bb1 expression levels were sufficient to provide adequate root protection against WCR regardless of soil environment, indicating that lowered Cry3Bb1 expression is not a contributing factor to the greater than expected WCR injury observed in some southwestern Nebraska maize fields.
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Affiliation(s)
- David S Wangila
- Department of Entomology, University of Nebraska- Lincoln, 220 Entomology Hall, Lincoln, NE, 68583, USA.
| | - Arnubio Valencia J
- Department of Entomology, University of Nebraska- Lincoln, 220 Entomology Hall, Lincoln, NE, 68583, USA
- Departamento de Producción Agropecuaria, Universidad de Caldas, Manizales, Colombia
| | - Haichuan Wang
- Department of Entomology, University of Nebraska- Lincoln, 220 Entomology Hall, Lincoln, NE, 68583, USA
| | - Blair D Siegfried
- Department of Entomology, University of Nebraska- Lincoln, 220 Entomology Hall, Lincoln, NE, 68583, USA
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, 32611, USA
| | - Lance J Meinke
- Department of Entomology, University of Nebraska- Lincoln, 220 Entomology Hall, Lincoln, NE, 68583, USA
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18
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Gressel J, Gassmann AJ, Owen MD. How well will stacked transgenic pest/herbicide resistances delay pests from evolving resistance? PEST MANAGEMENT SCIENCE 2017; 73:22-34. [PMID: 27598030 DOI: 10.1002/ps.4425] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Revised: 08/28/2016] [Accepted: 08/29/2016] [Indexed: 06/06/2023]
Abstract
Resistance has evolved to single transgenic traits engineered into crops for arthropod and herbicide resistances, and can be expected to evolve to the more recently introduced pathogen resistances. Combining transgenes against the same target pest is being promoted as the solution to the problem. This solution will work if used pre-emptively, but where resistance has evolved to one member of a stack, resistance should easily evolve for the second gene in most cases. We propose and elaborate criteria that could be used to evaluate the value of stacked traits for pest resistance management. Stacked partners must: target the same pest species; be in a tandem construct to preclude segregation; be synchronously expressed in the same tissues; have similar tissue persistence; target pest species that are still susceptible to at least two stacked partners. Additionally, transgene products must not be degraded in the same manner, and there should be a lack of cross-resistance to stacked transgenes or to their products. With stacked herbicide resistance transgenes, both herbicides must be used and have the same persistence. If these criteria are followed, and integrated with other pest management practices, resistance may be considerably delayed. © 2016 Society of Chemical Industry.
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Affiliation(s)
- Jonathan Gressel
- Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
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19
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Fishilevich E, Vélez AM, Storer NP, Li H, Bowling AJ, Rangasamy M, Worden SE, Narva KE, Siegfried BD. RNAi as a management tool for the western corn rootworm, Diabrotica virgifera virgifera. PEST MANAGEMENT SCIENCE 2016; 72:1652-1663. [PMID: 27218412 DOI: 10.1002/ps.4324] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Revised: 04/27/2016] [Accepted: 05/13/2016] [Indexed: 06/05/2023]
Abstract
The western corn rootworm (WCR), Diabrotica virgifera virgifera, is the most important pest of corn in the US Corn Belt. Economic estimates indicate that costs of control and yield loss associated with WCR damage exceed $US 1 billion annually. Historically, corn rootworm management has been extremely difficult because of its ability to evolve resistance to both chemical insecticides and cultural control practices. Since 2003, the only novel commercialized developments in rootworm management have been transgenic plants expressing Bt insecticidal proteins. Four transgenic insecticidal proteins are currently registered for rootworm management, and field resistance to proteins from the Cry3 family highlights the importance of developing traits with new modes of action. One of the newest approaches for controlling rootworm pests involves RNA interference (RNAi). This review describes the current understanding of the RNAi mechanisms in WCR and the use of this technology for WCR management. Further, the review addresses ecological risk assessment of RNAi and insect resistance management of RNAi for corn rootworm. © 2016 Society of Chemical Industry.
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Affiliation(s)
| | - Ana M Vélez
- Department of Entomology, University of Nebraska, Lincoln, NE, USA
| | | | | | | | | | | | | | - Blair D Siegfried
- Entomology and Nematology Department, University of Florida, Gainesville, FL, USA
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20
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Gassmann AJ, Shrestha RB, Jakka SRK, Dunbar MW, Clifton EH, Paolino AR, Ingber DA, French BW, Masloski KE, Dounda JW, St Clair CR. Evidence of Resistance to Cry34/35Ab1 Corn by Western Corn Rootworm (Coleoptera: Chrysomelidae): Root Injury in the Field and Larval Survival in Plant-Based Bioassays. JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:1872-1880. [PMID: 27329619 DOI: 10.1093/jee/tow110] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/03/2016] [Indexed: 06/06/2023]
Abstract
Western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a serious pest of corn in the United States, and recent management of western corn rootworm has included planting of Bt corn. Beginning in 2009, western corn rootworm populations with resistance to Cry3Bb1 corn and mCry3A corn were found in Iowa and elsewhere. To date, western corn rootworm populations have remained susceptible to corn producing Bt toxin Cry34/35Ab1. In this study, we used single-plant bioassays to test field populations of western corn rootworm for resistance to Cry34/35Ab1 corn, Cry3Bb1 corn, and mCry3A corn. Bioassays included nine rootworm populations collected from fields where severe injury to Bt corn had been observed and six control populations that had never been exposed to Bt corn. We found incomplete resistance to Cry34/35Ab1 corn among field populations collected from fields where severe injury to corn producing Cry34/35Ab1, either singly or as a pyramid, had been observed. Additionally, resistance to Cry3Bb1 corn and mCry3A corn was found among the majority of populations tested. These first cases of resistance to Cry34/35Ab1 corn, and the presence of resistance to multiple Bt toxins by western corn rootworm, highlight the potential vulnerability of Bt corn to the evolution of resistance by western corn rootworm. The use of more diversified management practices, in addition to insect resistance management, likely will be essential to sustain the viability of Bt corn for management of western corn rootworm.
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Affiliation(s)
- Aaron J Gassmann
- Department of Entomology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; ; ), Corresponding author, e-mail:
| | - Ram B Shrestha
- Department of Entomology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; ; )
| | - Siva R K Jakka
- Department of Entomology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; ; ), Current address: Valent U.S.A. Company, 3800 Old Leland Rd., Leland, MS 38756
| | - Mike W Dunbar
- Department of Entomology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; ; )
| | - Eric H Clifton
- Department of Entomology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; ; )
| | - Aubrey R Paolino
- Department of Entomology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; ; )
| | - David A Ingber
- Department of Entomology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; ; ), Current address: Department of Entomology and Wildlife Ecology, University of Delaware, Newark, DE 19716 , and
| | - B Wade French
- USDA ARS North Central Agricultural Research Laboratory, Brookings, SD
| | - Kenneth E Masloski
- Department of Entomology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; ; )
| | - John W Dounda
- Department of Entomology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; ; )
| | - Coy R St Clair
- Department of Entomology, Iowa State University, Ames, IA 50011 (; ; ; ; ; ; ; )
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21
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Jakka SRK, Shrestha RB, Gassmann AJ. Broad-spectrum resistance to Bacillus thuringiensis toxins by western corn rootworm (Diabrotica virgifera virgifera). Sci Rep 2016; 6:27860. [PMID: 27297953 PMCID: PMC4906537 DOI: 10.1038/srep27860] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 05/25/2016] [Indexed: 12/27/2022] Open
Abstract
The evolution of resistance and cross-resistance threaten the sustainability of genetically engineered crops that produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt). Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a serious pest of maize and has been managed with Bt maize since 2003. We conducted laboratory bioassays with maize hybrids producing Bt toxins Cry3Bb1, mCry3A, eCry3.1Ab, and Cry34/35Ab1, which represent all commercialized Bt toxins for management of western corn rootworm. We tested populations from fields where severe injury to Cry3Bb1 maize was observed, and populations that had never been exposed to Bt maize. Consistent with past studies, bioassays indicated that field populations were resistant to Cry3Bb1 maize and mCry3A maize, and that cross-resistance was present between these two types of Bt maize. Additionally, bioassays revealed resistance to eCry3.1Ab maize and cross-resistance among Cry3Bb1, mCry3A and eCry3.1Ab. However, no resistance or cross-resistance was detected for Cry34/35Ab1 maize. This broad-spectrum resistance illustrates the potential for insect pests to develop resistance rapidly to multiple Bt toxins when structural similarities are present among toxins, and raises concerns about the long-term durability of Bt crops for management of some insect pests.
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Affiliation(s)
- Siva R. K. Jakka
- Department of Entomology, Iowa State University, Ames, IA 50011, USA.
| | - Ram B. Shrestha
- Department of Entomology, Iowa State University, Ames, IA 50011, USA.
| | - Aaron J. Gassmann
- Department of Entomology, Iowa State University, Ames, IA 50011, USA.
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22
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Broad-spectrum resistance to Bacillus thuringiensis toxins by western corn rootworm (Diabrotica virgifera virgifera). Sci Rep 2016. [PMID: 27297953 DOI: 10.1038/srep27860.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The evolution of resistance and cross-resistance threaten the sustainability of genetically engineered crops that produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt). Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a serious pest of maize and has been managed with Bt maize since 2003. We conducted laboratory bioassays with maize hybrids producing Bt toxins Cry3Bb1, mCry3A, eCry3.1Ab, and Cry34/35Ab1, which represent all commercialized Bt toxins for management of western corn rootworm. We tested populations from fields where severe injury to Cry3Bb1 maize was observed, and populations that had never been exposed to Bt maize. Consistent with past studies, bioassays indicated that field populations were resistant to Cry3Bb1 maize and mCry3A maize, and that cross-resistance was present between these two types of Bt maize. Additionally, bioassays revealed resistance to eCry3.1Ab maize and cross-resistance among Cry3Bb1, mCry3A and eCry3.1Ab. However, no resistance or cross-resistance was detected for Cry34/35Ab1 maize. This broad-spectrum resistance illustrates the potential for insect pests to develop resistance rapidly to multiple Bt toxins when structural similarities are present among toxins, and raises concerns about the long-term durability of Bt crops for management of some insect pests.
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23
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Martinez JC, Caprio MA. IPM Use With the Deployment of a Non-High Dose Bt Pyramid and Mitigation of Resistance for Western Corn Rootworm (Diabrotica virgifera virgifera). ENVIRONMENTAL ENTOMOLOGY 2016; 45:747-761. [PMID: 27018423 DOI: 10.1093/ee/nvw015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 02/09/2016] [Indexed: 06/05/2023]
Abstract
Recent detection of western corn rootworm resistance to Bt (Bacillus thuringiensis) corn prompted recommendations for the use of integrated pest management (IPM) with planting refuges to prolong the durability of Bt technologies. We conducted a simulation experiment exploring the effectiveness of various IPM tools at extending durability of pyramided Bt traits. Results indicate that some IPM practices have greater merits than others. Crop rotation was the most effective strategy, followed by increasing the non-Bt refuge size from 5 to 20%. Soil-applied insecticide use for Bt corn did not increase the durability compared with planting Bt with refuges alone, and both projected lower durabilities. When IPM participation with randomly selected management tools was increased at the time of Bt commercialization, durability of pyramided traits increased as well. When non-corn rootworm expressing corn was incorporated as an IPM option, the durability further increased. For corn rootworm, a local resistance phenomenon appeared immediately surrounding the resistant field (hotspot) and spread throughout the local neighborhood in six generations in absence of mitigation. Hotspot mitigation with random selection of strategies was ineffective at slowing resistance, unless crop rotation occurred immediately; regional mitigation was superior to random mitigation in the hotspot and reduced observed resistance allele frequencies in the neighborhood. As resistance alleles of mobile pests can escape hotspots, the scope of mitigation should extend beyond resistant sites. In the case of widespread resistance, regional mitigation was less effective at prolonging the life of the pyramid than IPM with Bt deployment at the time of commercialization.
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Affiliation(s)
- J C Martinez
- 1US EPA Office of Pesticide Programs, 1200 Pennsylvania Ave, NW, Mail Code 7511-P, Washington, DC 20460 (; )
| | - M A Caprio
- 3Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762
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Gassmann AJ. Resistance to Bt maize by western corn rootworm: insights from the laboratory and the field. CURRENT OPINION IN INSECT SCIENCE 2016; 15:111-115. [PMID: 27436740 DOI: 10.1016/j.cois.2016.04.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/11/2016] [Accepted: 04/06/2016] [Indexed: 06/06/2023]
Abstract
Western corn rootworm is a serious pest of maize. Beginning in 2003, management of western corn rootworm included transgenic maize that produces insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt). The first Bt maize hybrids produced Cry3Bb1, but additional Bt toxins have since been introduced, including eCry3.1Ab, mCry3A and Cry34/35Ab1. Laboratory selection experiments found that western corn rootworm could develop resistance to all types of Bt maize following three to seven generations of selection. By 2009 cases of field-evolved resistance to Cry3Bb1 maize had been identified, with populations also showing cross-resistance to mCry3A maize. Factors likely contributing to resistance were the lack of a high dose of Bt toxin for maize targeting rootworm and minimal fitness costs of resistance.
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Affiliation(s)
- Aaron J Gassmann
- Department of Entomology, Iowa State University, Ames, IA 50011, United States.
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Shrestha RB, Jakka SRK, French BW, Gassmann AJ. Field-Based Assessment of Resistance to Bt Corn by Western Corn Rootworm (Coleoptera: Chrysomelidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:1399-1409. [PMID: 27122498 DOI: 10.1093/jee/tow087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 03/29/2016] [Indexed: 06/05/2023]
Abstract
Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a serious pest of corn and is managed with corn that produces insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt). Beginning in 2009, resistance to Cry3Bb1 corn, and severe injury to Cry3Bb1 corn in the field, was observed in Iowa. However, few data exist on how Cry3Bb1-resistant western corn rootworm interact with various management practices in the field. Using a field experiment, we measured adult emergence and feeding injury to corn roots for both Cry3Bb1-resistant and Cry3Bb1-susceptible populations of western corn rootworm when tested against various Bt corn hybrids and a soil-applied insecticide. Between 2012 and 2013, we evaluated five fields that were associated with greater than one node of feeding injury to Cry3Bb1 corn by western corn rootworm (i.e., problem-field populations), and a laboratory strain that had never been exposed to Bt corn (i.e., control population). Adult emergence for western corn rootworm and root injury to corn were significantly higher in problem-field populations than control populations for both Cry3Bb1 corn and mCry3A corn. By contrast, corn with Cry34/35Ab1, either alone or pyramided with Cry3Bb1, significantly reduced adult emergence and root injury in both problem fields and control fields. In problem fields, application of the soil-applied insecticide to Cry3Bb1 corn significantly reduced root injury, but not adult emergence. Our results are discussed in terms of developing strategies for managing western corn rootworm with resistance to Cry3Bb1 and mCry3A, and delaying the additional evolution of Bt resistance by this pest.
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Fishilevich E, Vélez AM, Khajuria C, Frey MLF, Hamm RL, Wang H, Schulenberg GA, Bowling AJ, Pence HE, Gandra P, Arora K, Storer NP, Narva KE, Siegfried BD. Use of chromatin remodeling ATPases as RNAi targets for parental control of western corn rootworm (Diabrotica virgifera virgifera) and Neotropical brown stink bug (Euschistus heros). INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2016; 71:58-71. [PMID: 26873291 DOI: 10.1016/j.ibmb.2016.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 02/04/2016] [Accepted: 02/04/2016] [Indexed: 06/05/2023]
Abstract
RNA interference (RNAi) is a gene silencing mechanism that is present in animals and plants and is triggered by double stranded RNA (dsRNA) or small interfering RNA (siRNA), depending on the organism. In the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), RNAi can be achieved by feeding rootworms dsRNA added to artificial diet or plant tissues transformed to express dsRNA. The effect of RNAi depends on the targeted gene function and can range from an absence of phenotypic response to readily apparent responses, including lethality. Furthermore, RNAi can directly affect individuals that consume dsRNA or the effect may be transferred to the next generation. Our previous work described the potential use of genes involved in embryonic development as a parental RNAi technology for the control of WCR. In this study, we describe the use of chromatin-remodeling ATPases as target genes to achieve parental gene silencing in two insect pests, a coleopteran, WCR, and a hemipteran, the Neotropical brown stink bug, Euschistus heros Fabricius (Hemiptera: Pentatomidae). Our results show that dsRNA targeting chromatin-remodeling ATPase transcripts, brahma, mi-2, and iswi strongly reduced the fecundity of the exposed females in both insect species. Additionally, knockdown of chd1 reduced the fecundity of E. heros.
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Affiliation(s)
- Elane Fishilevich
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN, United States
| | - Ana M Vélez
- University of Nebraska, Department of Entomology, 103 Entomology Hall, Lincoln, NE 68583-0816, United States
| | - Chitvan Khajuria
- University of Nebraska, Department of Entomology, 103 Entomology Hall, Lincoln, NE 68583-0816, United States
| | - Meghan L F Frey
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN, United States
| | - Ronda L Hamm
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN, United States
| | - Haichuan Wang
- University of Nebraska, Department of Entomology, 103 Entomology Hall, Lincoln, NE 68583-0816, United States
| | | | - Andrew J Bowling
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN, United States
| | - Heather E Pence
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN, United States
| | - Premchand Gandra
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN, United States
| | - Kanika Arora
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN, United States
| | - Nicholas P Storer
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN, United States
| | - Kenneth E Narva
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN, United States
| | - Blair D Siegfried
- Entomology and Nematology Department, Charles Steinmetz Hall, University of Florida, P.O. Box 110620, Gainesville, FL 32611-0620, United States.
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Nair R, Kamath SP, Mohan KS, Head G, Sumerford DV. Inheritance of field-relevant resistance to the Bacillus thuringiensis protein Cry1Ac in Pectinophora gossypiella (Lepidoptera: Gelechiidae) collected from India. PEST MANAGEMENT SCIENCE 2016; 72:558-565. [PMID: 25864528 DOI: 10.1002/ps.4023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 04/02/2015] [Accepted: 04/02/2015] [Indexed: 05/29/2023]
Abstract
BACKGROUND The inheritance and phenotypic expression of resistance to Bacillus thuringiensis Cry1Ac insecticidal protein were studied in selected populations of pink bollworm, Pectinophora gossypiella (Saunders), that were collected from Bollgard cotton in India. The individual populations in the pool were Cry1Ac resistant and sourced from Cry1Ac-containing Bt cotton (Bollgard) hybrids in 2010. RESULTS Laboratory selection on diet with 1.0 µg Cry1Ac protein mL(-1) increased the percentage reaching at least third instar from 7% in the F3 generation to 94% in the F15 generation, a 257-fold increase in median lethal concentration relative to the susceptible strain. Analysis of reciprocal genetic crosses between the Cry1Ac-resistant strain NKJ and a susceptible laboratory strain MRC showed a dominance of 0.22, indicating that the inheritance of Cry1Ac resistance is partially recessive at Cry1Ac concentrations comparable with those in Bollgard. Analyses of backcrosses of F1 hybrid moths with NKJ and MRC indicated that resistance is autosomal. The Cry1Ac-resistant strain exhibited little or no cross-resistance to the Cry2Ab2 protein. CONCLUSION This is the first study of the dominance of Cry1Ac field resistance in P. gossypiella. The results provide the basis for refining resistance management strategies for Bt cotton.
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Affiliation(s)
- Rupa Nair
- Monsanto Research Centre, Bangalore, Karnataka, India
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Andow DA, Pueppke SG, Schaafsma AW, Gassmann AJ, Sappington TW, Meinke LJ, Mitchell PD, Hurley TM, Hellmich RL, Porter RP. Early Detection and Mitigation of Resistance to Bt Maize by Western Corn Rootworm (Coleoptera: Chrysomelidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:1-12. [PMID: 26362989 DOI: 10.1093/jee/tov238] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 07/17/2015] [Indexed: 05/25/2023]
Abstract
Transgenic Bt maize that produces less than a high-dose has been widely adopted and presents considerable insect resistance management (IRM) challenges. Western corn rootworm, Diabrotica virgifera virgifera LeConte, has rapidly evolved resistance to Bt maize in the field, leading to local loss of efficacy for some corn rootworm Bt maize events. Documenting and responding to this resistance has been complicated by a lack of rapid diagnostic bioassays and by regulatory triggers that hinder timely and effective management responses. These failures are of great concern to the scientific and agricultural community. Specific challenges posed by western corn rootworm resistance to Bt maize, and more general concerns around Bt crops that produce less than a high-dose of Bt toxin, have caused uncertainty around current IRM protocols. More than 15 years of experience with IRM has shown that high-dose and refuge-based IRM is not applicable to Bt crops that produce less than a high-dose. Adaptive IRM approaches and pro-active, integrated IRM-pest management strategies are needed and should be in place before release of new technologies that produce less than a high-dose. We suggest changes in IRM strategies to preserve the utility of corn rootworm Bt maize by 1) targeting local resistance management earlier in the sequence of responses to resistance and 2) developing area-wide criteria to address widespread economic losses. We also favor consideration of policies and programs to counteract economic forces that are contributing to rapid resistance evolution.
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Affiliation(s)
- David A Andow
- Department of Entomology, University of Minnesota, St. Paul, MN 55108 ,
| | - Steven G Pueppke
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824
| | - Arthur W Schaafsma
- University of Guelph Ridgetown Campus, Ridgetown, Ontario, Canada N0P 2C0
| | | | | | - Lance J Meinke
- Department of Entomology, University of Nebraska, Lincoln, NE 68583
| | - Paul D Mitchell
- Department of Agricultural and Applied Economics, University of Wisconsin, Madison, WI 53706
| | - Terrance M Hurley
- Department of Applied Economics, University of Minnesota, St. Paul, MN 55108 , and
| | - Richard L Hellmich
- USDA-ARS, Corn Insects & Crop Genetics Research Unit, Ames, IA 50011 (; )
| | - R Pat Porter
- Texas A&M Agrilife Research and Extension Center, Lubbock, TX 79403
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Huesing JE, Andres D, Braverman MP, Burns A, Felsot AS, Harrigan GG, Hellmich RL, Reynolds A, Shelton AM, Jansen van Rijssen W, Morris EJ, Eloff JN. Global Adoption of Genetically Modified (GM) Crops: Challenges for the Public Sector. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:394-402. [PMID: 26751159 DOI: 10.1021/acs.jafc.5b05116] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Advances in biotechnology continue to drive the development of a wide range of insect-protected, herbicide-tolerant, stress-tolerant, and nutritionally enhanced genetically modified (GM) crops, yet societal and public policy considerations may slow their commercialization. Such restrictions may disproportionately affect developing countries, as well as smaller entrepreneurial and public sector initiatives. The 2014 IUPAC International Congress of Pesticide Chemistry (San Francisco, CA, USA; August 2014) included a symposium on "Challenges Associated with Global Adoption of Agricultural Biotechnology" to review current obstacles in promoting GM crops. Challenges identified by symposium presenters included (i) poor public understanding of GM technology and the need for enhanced communication strategies, (ii) nonharmonized and prescriptive regulatory requirements, and (iii) limited experience with regulations and product development within some public sector programs. The need for holistic resistance management programs to enable the most effective use of insect-protected crops was also a point of emphasis. This paper provides details on the symposium discussion and provides background information that can be used in support of further adoption of beneficial GM crops. Overall, it emphasizes that global adoption of modern agricultural biotechnology has not only provided benefits to growers and consumers but has great potential to provide solutions to an increasing global population and diminishing agricultural land. This potential will be realized by continued scientific innovation, harmonized regulatory systems, and broader communication of the benefits of the high-yielding, disease-resistant, and nutritionally enhanced crops attainable through modern biotechnology.
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Affiliation(s)
- Joseph E Huesing
- Bureau for Food Security, Research Division, U.S. Agency for International Development , Washington, D.C. 20004, United States
| | - David Andres
- Bayer Cropscience AG, Alfred-Nobel-Strasse 50, 40789 Monheim, Germany
- Representing Europabio, Avenue de l'Armée 6, 1040 Etterbeek, Belgium
| | - Michael P Braverman
- IR-4 Project, Rutgers University , Princeton, New Jersey 08540, United States
| | - Andrea Burns
- Syngenta Crop Protection, LLC, 3054 East Cornwallis Road, Research Triangle Park, North Carolina 27709, United States
| | - Allan S Felsot
- Department of Entomology, Washington State University , Richland, Washington 99354, United States
| | - George G Harrigan
- Monsanto Company, 800 North Lindbergh Boulevard, St. Louis, Missouri 63167, United States
| | - Richard L Hellmich
- USDA-ARS, Corn Insects and Crop Genetics Research Unit and Department of Entomology, Iowa State University , Ames, Iowa 50011, United States
| | - Alan Reynolds
- Biopesticides and Pollution Prevention Division, U.S. Environmental Protection Agency , Washington, D.C. 20460, United States
| | - Anthony M Shelton
- Department of Entomology, Cornell University/NYSAES , Geneva, New York 14456, United States
| | - Wilna Jansen van Rijssen
- Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria , Private Bag X04, Onderstepoort 0110, South Africa
| | - E Jane Morris
- School of Biology, University of Leeds , Leeds LS2 9JT, United Kingdom
| | - Jacobus N Eloff
- Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria , Private Bag X04, Onderstepoort 0110, South Africa
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Deitloff J, Dunbar MW, Ingber DA, Hibbard BE, Gassmann AJ. Effects of refuges on the evolution of resistance to transgenic corn by the western corn rootworm, Diabrotica virgifera virgifera LeConte. PEST MANAGEMENT SCIENCE 2016; 72:190-198. [PMID: 25652190 DOI: 10.1002/ps.3988] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 01/05/2015] [Accepted: 01/29/2015] [Indexed: 06/04/2023]
Abstract
BACKGROUND Diabrotica virgifera virgifera LeConte is a major pest of corn and causes over a billion dollars of economic loss annually through yield reductions and management costs. Corn producing toxins derived from Bacillus thuringiensis (Bt) has been developed to help manage D. v. virgifera. However, previous studies have demonstrated the ability of this species to evolve resistance to Bt toxins in both laboratory and field settings. RESULTS We used an experimental evolution approach to test the refuge strategies for delaying resistance of D. v. virgifera to corn producing Bt toxin Cry34/35Ab1. In the absence of refuges, D. v. virgifera developed resistance to Bt corn after three generations of selection. In some cases, non-Bt refuges reduced the level of resistance compared with the strain selected in the absence of refuges, but refuge strains did show reduced susceptibility to Bt corn compared with the unselected strain. CONCLUSIONS In this study, non-Bt refuges delayed resistance to Bt corn by D. v. virgifera in some cases but not others. Combining the refuge strategy with pyramids of multiple Bt toxins and applying other pest management strategies will likely be necessary to delay resistance of D. v. virgifera to Bt corn.
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Affiliation(s)
- Jennifer Deitloff
- Department of Entomology, Iowa State University, Ames, IA, USA
- Department of Biological Sciences, Lock Haven University, Lock Haven, PA, USA
| | - Mike W Dunbar
- Department of Entomology, Iowa State University, Ames, IA, USA
| | - David A Ingber
- Department of Entomology, Iowa State University, Ames, IA, USA
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Ingber DA, Gassmann AJ. Inheritance and Fitness Costs of Resistance to Cry3Bb1 Corn by Western Corn Rootworm (Coleoptera: Chrysomelidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2015; 108:2421-2432. [PMID: 26453731 DOI: 10.1093/jee/tov199] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 06/18/2015] [Indexed: 06/05/2023]
Abstract
Transgenic crops that produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are widely planted to manage pest insects. One of the primary pests targeted by Bt corn in the United States is western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae). Cry3Bb1 corn for management of western corn rootworm was commercialized in 2003, and beginning in 2009, populations of western corn rootworm with field-evolved resistance to Cry3Bb1 corn were found in Iowa. Here we quantify the magnitude, inheritance, and fitness costs of resistance to Cry3Bb1 corn in two strains (Hopkinton and Cresco) derived from field populations that evolved resistance to Cry3Bb1 corn. For Hopkinton, we found evidence for complete resistance to Cry3Bb1 corn and nonrecessive inheritance. Additionally, no fitness costs of Cry3Bb1 resistance were detected for Hopkinton. For Cresco, resistance was incomplete and recessive, and we detected fitness costs affecting developmental rate, survival to adulthood, and fecundity. These results suggest that variation may exist among field populations in both the inheritance and accompanying fitness costs of resistance. To the extent that field populations exhibit nonrecessive inheritance and a lack of fitness cost, this will favor more rapid evolution of resistance than would be expected when resistance is functionally recessive and is accompanied by fitness costs.
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Affiliation(s)
- David A Ingber
- Department of Entomology, Iowa State University, Ames, IA 50011. Current Address: Department of Entomology and Wildlife Ecology, University of Delaware, Newark, DE 19716.
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32
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Wangila DS, Gassmann AJ, Petzold-Maxwell JL, French BW, Meinke LJ. Susceptibility of Nebraska Western Corn Rootworm (Coleoptera: Chrysomelidae) Populations to Bt Corn Events. JOURNAL OF ECONOMIC ENTOMOLOGY 2015; 108:742-51. [PMID: 26470186 DOI: 10.1093/jee/tou063] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 12/03/2014] [Indexed: 05/16/2023]
Abstract
Transgenic plants have been widely adopted by growers to manage the western corn rootworm, Diabrotica virgifera virgifera LeConte, in field corn. Because of reduced efficacy in some Nebraska fields after repeated use of Cry3Bb1-expressing hybrids, single plant bioassays were conducted in 2012 and 2013 to characterize the susceptibility of western corn rootworm populations to the rootworm-active proteins Cry3Bb1, mCry3A, and Cry34/35Ab1. Results demonstrate that there are heritable differences in susceptibility of Nebraska western corn rootworm populations to rootworm-active Bt traits. Proportional survival and corrected survival data coupled with field histories collectively support the conclusion that a level of field resistance to Cry3Bb1 has evolved in some Nebraska populations in response to selection pressure and that cross-resistance exists between Cry3Bb1 and mCry3A. There was no apparent cross-resistance between Cry34/35Ab1 and either Cry3Bb1 or mCry3A. The potential implications of these results on current and future corn rootworm management strategies are discussed.
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Affiliation(s)
- David S Wangila
- Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE 68583
| | - Aaron J Gassmann
- Department of Entomology, Iowa State University, 18 Insectary, Ames, IA 50011
| | - Jennifer L Petzold-Maxwell
- Department of Entomology, Iowa State University, 18 Insectary, Ames, IA 50011. Current address: Department of Biology, 100 Wartburg Blvd., Wartburg College, Waverly, IA 50677
| | - B Wade French
- North Central Agricultural Research Laboratory, USDA-ARS, Brookings, SD 57006
| | - Lance J Meinke
- Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE 68583. Corresponding author, e-mail:
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Keweshan RS, Head GP, Gassmann AJ. Effects of Pyramided Bt Corn and Blended Refuges on Western Corn Rootworm and Northern Corn Rootworm (Coleoptera: Chrysomelidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2015; 108:720-729. [PMID: 26470183 DOI: 10.1093/jee/tov005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 12/14/2014] [Indexed: 06/05/2023]
Abstract
The western corn rootworm, Diabrotica virgifera virgifera LeConte, and the northern corn rootworm, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae), are major pests of corn (Zea mays L). Several transgenic corn events producing insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) kill corn rootworm larvae and reduce injury to corn roots. However, planting of Bt corn imposes selection on rootworm populations to evolve Bt resistance. The refuge strategy and pyramiding of multiple Bt toxins can delay resistance to Bt crops. In this study, we assessed the impact of four treatments--1) non-Bt corn, 2) Cry3Bb1 corn, 3) corn pyramided with Cry3Bb1 and Cry34/35Ab1, and 4) pyramided corn with a blended refuge--on survival, time of adult emergence, and size of western and northern corn rootworm. All treatments with Bt corn led to significant reductions in the number of adults that emerged per plot. However, at one location, we identified Cry3Bb1-resistant western corn rootworm. In some cases Bt treatments reduced size of adults and delayed time of adult emergence, with effects most pronounced for pyramided corn. For both species, the number of adults that emerged from pyramided corn with a blended refuge was significantly lower than expected, based solely on emergence from pure stands of pyramided corn and non-Bt corn. The results of this study indicate that pyramided corn with a blended refuge substantially reduces survival of both western and northern corn rootworm, and as such, should be a useful tool within the context of a broader integrated pest management strategy.
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Affiliation(s)
- Ryan S Keweshan
- Department of Entomology, Iowa State University, Ames, IA 50011. Current Address: Department of Biology, Utah State University, Logan, UT 84321
| | | | - Aaron J Gassmann
- Department of Entomology, Iowa State University, Ames, IA 50011.
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34
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Abstract
Western corn rootworm (WCR) is a major maize (Zea mays L.) pest leading to annual economic losses of more than 1 billion dollars in the United States. Transgenic maize expressing insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are widely used for the management of WCR. However, cultivation of Bt-expressing maize places intense selection pressure on pest populations to evolve resistance. Instances of resistance to Bt toxins have been reported in WCR. Developing genetic markers for resistance will help in characterizing the extent of existing issues, predicting where future field failures may occur, improving insect resistance management strategies, and in designing and sustainably implementing forthcoming WCR control products. Here, we discover and validate genetic markers in WCR that are associated with resistance to the Cry3Bb1 Bt toxin. A field-derived WCR population known to be resistant to the Cry3Bb1 Bt toxin was used to generate a genetic map and to identify a genomic region associated with Cry3Bb1 resistance. Our results indicate that resistance is inherited in a nearly recessive manner and associated with a single autosomal linkage group. Markers tightly linked with resistance were validated using WCR populations collected from Cry3Bb1 maize fields showing significant WCR damage from across the US Corn Belt. Two markers were found to be correlated with both diet (R2 = 0.14) and plant (R2 = 0.23) bioassays for resistance. These results will assist in assessing resistance risk for different WCR populations, and can be used to improve insect resistance management strategies.
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35
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Whiting SA, Strain KE, Campbell LA, Young BG, Lydy MJ. A multi-year field study to evaluate the environmental fate and agronomic effects of insecticide mixtures. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 497-498:534-542. [PMID: 25163650 DOI: 10.1016/j.scitotenv.2014.07.115] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 07/29/2014] [Accepted: 07/29/2014] [Indexed: 06/03/2023]
Abstract
A mixture of insecticides used in corn production was monitored over a three-year period in a field study to determine how long each persists in the environment, where each insecticide travels within the corn field, and the efficacy of using soil-applied insecticides with genetically modified corn. The genetically modified corn contained the insecticidal Cry1Ab and Cry3Bb1 proteins (Bt corn) and the Cry1Ab protein was found to persist only during the corn growing season in soil, runoff water, and runoff sediment with highest concentrations measured during pollination. Very low concentrations of Cry1Ab proteins were measured in soil collected in the non-Bt corn field, and no Cry1Ab proteins were detected in shallow groundwater or soil pore water. Clothianidin, a neonicotinoid insecticide used as a seed coating, was detected in all matrices and remained persistent throughout the year in soil pore water. Tefluthrin, a pyrethroid insecticide applied at planting to control corn rootworm larvae (Diabrotica spp., Coleoptera: Chrysomelidae) populations, was consistently detected in soil, runoff water, and runoff sediment during the corn growing season, but was not detected in groundwater or soil pore water. Tefluthrin did not have an effect on root damage from corn rootworm larvae feeding to Bt corn, but did prevent damage to non-Bt corn. A slight reduction in grain yield was observed in the non-Bt, no tefluthrin treatment when compared to all other treatments, but no significant difference in grain yield was observed among Bt corn treatments regardless of soil insecticide application. In the current study, the use of tefluthrin on Bt corn did not significantly affect crop damage or yield, and tefluthrin may travel off-site in runoff water and sediment.
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Affiliation(s)
- Sara A Whiting
- Center for Fisheries, Aquaculture, and Aquatic Sciences and Department of Zoology, 1125 Lincoln Dr., Southern Illinois University, Carbondale, IL 62901, USA.
| | - Katherine E Strain
- Center for Fisheries, Aquaculture, and Aquatic Sciences and Department of Zoology, 1125 Lincoln Dr., Southern Illinois University, Carbondale, IL 62901, USA.
| | - Laura A Campbell
- Plant, Soil, and Agricultural Systems Department, 1205 Lincoln Dr., Southern Illinois University, Carbondale, IL 62901, USA.
| | - Bryan G Young
- Plant, Soil, and Agricultural Systems Department, 1205 Lincoln Dr., Southern Illinois University, Carbondale, IL 62901, USA.
| | - Michael J Lydy
- Center for Fisheries, Aquaculture, and Aquatic Sciences and Department of Zoology, 1125 Lincoln Dr., Southern Illinois University, Carbondale, IL 62901, USA.
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Field-evolved resistance by western corn rootworm to multiple Bacillus thuringiensis toxins in transgenic maize. Proc Natl Acad Sci U S A 2014; 111:5141-6. [PMID: 24639498 DOI: 10.1073/pnas.1317179111] [Citation(s) in RCA: 210] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The widespread planting of crops genetically engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) places intense selective pressure on pest populations to evolve resistance. Western corn rootworm is a key pest of maize, and in continuous maize fields it is often managed through planting of Bt maize. During 2009 and 2010, fields were identified in Iowa in which western corn rootworm imposed severe injury to maize producing Bt toxin Cry3Bb1. Subsequent bioassays revealed Cry3Bb1 resistance in these populations. Here, we report that, during 2011, injury to Bt maize in the field expanded to include mCry3A maize in addition to Cry3Bb1 maize and that laboratory analysis of western corn rootworm from these fields found resistance to Cry3Bb1 and mCry3A and cross-resistance between these toxins. Resistance to Bt maize has persisted in Iowa, with both the number of Bt fields identified with severe root injury and the ability western corn rootworm populations to survive on Cry3Bb1 maize increasing between 2009 and 2011. Additionally, Bt maize targeting western corn rootworm does not produce a high dose of Bt toxin, and the magnitude of resistance associated with feeding injury was less than that seen in a high-dose Bt crop. These first cases of resistance by western corn rootworm highlight the vulnerability of Bt maize to further evolution of resistance from this pest and, more broadly, point to the potential of insects to develop resistance rapidly when Bt crops do not achieve a high dose of Bt toxin.
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Insect resistance to Bt crops: lessons from the first billion acres. Nat Biotechnol 2013; 31:510-21. [DOI: 10.1038/nbt.2597] [Citation(s) in RCA: 681] [Impact Index Per Article: 61.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 03/26/2013] [Indexed: 01/14/2023]
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Rudeen ML, Gassmann AJ. Effects of Cry34/35Ab1 corn on the survival and development of western corn rootworm, Diabrotica virgifera virgifera. PEST MANAGEMENT SCIENCE 2013; 69:709-716. [PMID: 23109348 DOI: 10.1002/ps.3425] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 08/24/2012] [Accepted: 09/19/2012] [Indexed: 06/01/2023]
Abstract
BACKGROUND The western corn rootworm, Diabrotica virgifera virgifera LeConte, is a major agricultural pest that is managed with transgenic corn, Zea mays L., expressing genes from Bacillus thuringiensis Berliner (Bt). The effects of Bt corn producing Cry34/35Ab1 (event DAS-59122-7) and entomopathogens on the survival and development of larval D. v. virgifera were examined in laboratory, field and greenhouse experiments. RESULTS Larvae preferred non-Bt over Bt corn in a laboratory experiment, and there was higher recovery from non-Bt corn than from Bt corn in a field experiment. In a greenhouse study, survival at 17 days did not differ significantly among non-Bt corn, Bt corn and a blend of Bt and non-Bt corn, but development was delayed on Bt corn. Older larvae fed non-Bt corn had lower survival when entomopathogenic nematodes were added, but no other effects of pathogen were detected. CONCLUSION Bt corn producing Cry34/35Ab1 delayed larval development of D. v. virgifera and deterred feeding. In a mixture of Bt and non-Bt corn, larval development and survival were similar to non-Bt corn alone, suggesting that non-Bt plants in a blended refuge or a pure stand may produce a similar number of adult insects, and that timing of adult emergence may also be similar.
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Scientific Opinion on an application from Pioneer Hi‐Bred International and Dow AgroSciences LLC (EFSA‐GMO‐NL‐2005‐23) for placing on the market of genetically modified maize 59122 for food and feed uses, import, processing and cultivation under Regulation (EC) No 1829/2003. EFSA J 2013. [DOI: 10.2903/j.efsa.2013.3135] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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Transgenic approaches to western corn rootworm control. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2013; 136:135-62. [PMID: 23604211 DOI: 10.1007/10_2013_195] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) is a significant corn pest throughout the United States corn belt. Rootworm larvae feed on corn roots causing yield losses and control expenditures that are estimated to exceed US$1 billion annually. Traditional management practices to control rootworms such as chemical insecticides or crop rotation have suffered reduced effectiveness due to the development of physiological and behavioral resistance. Transgenic maize expressing insecticidal proteins are very successful in protecting against rootworm damage and preserving corn yield potential. However, the high rate of grower adoption and early reliance on hybrids expressing a single mode of action and low-dose traits threatens the durability of commercialized transgenic rootworm technology for rootworm control. A summary of current transgenic approaches for rootworm control and the corresponding insect resistance management practices is included. An overview of potential new modes of action based on insecticidal proteins, and especially RNAi targeting mRNA coding for essential insect proteins is provided.
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Meihls LN, Higdon ML, Ellersieck MR, Tabashnik BE, Hibbard BE. Greenhouse-selected resistance to Cry3Bb1-producing corn in three western corn rootworm populations. PLoS One 2012; 7:e51055. [PMID: 23284656 PMCID: PMC3527414 DOI: 10.1371/journal.pone.0051055] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Accepted: 10/29/2012] [Indexed: 01/12/2023] Open
Abstract
Transgenic corn producing the Bacillus thuringiensis (Bt) toxin Cry3Bb1 has been useful for controlling western corn rootworm, Diabrotica virgifera virgifera LeConte, one of the most economically important crop pests in the United States. However, rapid evolution of resistance by this beetle to Bt corn producing Cry3Bb1 has been reported previously from the laboratory, greenhouse, and field. Here we selected in the greenhouse for resistance to Cry3Bb1 corn in three colonies of WCR derived from Kansas, Minnesota, and Wisconsin, respectively. Three generations of rearing on Cry3Bb1 corn significantly increased larval survival on Cry3Bb1 corn, resulting in similar survival in the greenhouse for selected colonies on Cry3Bb1 corn and isoline corn that does not produce Bt toxin. After four to seven generations of rearing on Cry3Bb1 corn, survival in the field on Cry3Bb1 corn relative to isoline corn more than doubled for selected colonies (72%) compared with control colonies (33%). For both selected and control colonies, survival in the field was significantly lower on Cry3Bb1 corn than on isoline corn. On isoline corn, most fitness components were similar for selected colonies and control colonies. However, fecundity was significantly lower for selected colonies than control colonies, indicating a fitness cost associated with resistance. The rapid evolution of resistance by western corn rootworm to Bt corn reported here and previously underlines the importance of effective resistance management for this pest.
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Affiliation(s)
- Lisa N Meihls
- Plant-Insect Interactions, The Boyce Thompson Institute for Plant Research, Ithaca, New York, United States of America.
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Resistance evolution to the first generation of genetically modified Diabrotica-active Bt-maize events by western corn rootworm: management and monitoring considerations. Transgenic Res 2012; 22:269-99. [DOI: 10.1007/s11248-012-9657-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Accepted: 09/07/2012] [Indexed: 01/21/2023]
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