1
|
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: 25] [Impact Index Per Article: 25.0] [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.
Collapse
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
| |
Collapse
|
2
|
Carrière Y, Degain BA, Tabashnik BE. Effects of gene flow between Bt and non-Bt plants in a seed mixture of Cry1A.105 + Cry2Ab corn on performance of corn earworm in Arizona. PEST MANAGEMENT SCIENCE 2021; 77:2106-2113. [PMID: 33350567 DOI: 10.1002/ps.6239] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/08/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND Using natural populations of Helicoverpa zea from Arizona, we tested the hypotheses that gene flow between Bacillus thuringiensis (Bt) plants and non-Bt plants in a seed mixture of 10% non-Bt corn and 90% Bt corn producing Cry1A.105 and Cry2Ab reduces larval performance on ears from non-Bt plants, or increases performance on ears from Bt plants. RESULTS Gene flow was not detected in blocks of non-Bt or Bt corn but was extensive in seed mixtures. Analyses of larval weight and abundance over a period of 3 to 4 weeks did not indicate consistent effects of gene flow on development rate and survival. However for non-Bt plants, the ear area damaged and percentage of ears with exit holes were significantly lower in the seed mixtures than blocks. By contrast, the percentage of ears with exit holes and ear damage did not differ significantly between the seed mixtures and blocks for Bt plants. Nearly 100% of the ears were damaged and the damaged area was substantial, showing that H. zea is a major ear-feeding pest in Arizona. Relative to non-Bt corn, the pyramided Bt corn did not significantly reduce the percentage of damaged ears and only reduced the ear area damaged by 21 to 39%, indicating that H. zea may have evolved resistance to Cry1A.105, Cry2Ab, or both. CONCLUSIONS Our results indicate that gene flow between Bt and non-Bt plants in seed mixtures reduced effective refuge size, and that block refuges may be needed to manage the evolution of H. zea resistance to Bt corn in Arizona. © 2020 Society of Chemical Industry.
Collapse
Affiliation(s)
- Yves Carrière
- Department of Entomology, University of Arizona, Tucson, AZ, USA
| | - Ben A Degain
- Department of Entomology, University of Arizona, Tucson, AZ, USA
| | | |
Collapse
|
3
|
Carrière Y, Brown ZS, Downes SJ, Gujar G, Epstein G, Omoto C, Storer NP, Mota-Sanchez D, Søgaard Jørgensen P, Carroll SP. Governing evolution: A socioecological comparison of resistance management for insecticidal transgenic Bt crops among four countries. AMBIO 2020; 49:1-16. [PMID: 30903512 PMCID: PMC6889122 DOI: 10.1007/s13280-019-01167-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 02/01/2019] [Accepted: 03/01/2019] [Indexed: 05/10/2023]
Abstract
Cooperative management of pest susceptibility to transgenic Bacillus thuringiensis (Bt) crops is pursued worldwide in a variety of forms and to varying degrees of success depending on context. We examine this context using a comparative socioecological analysis of resistance management in Australia, Brazil, India, and the United States. We find that a shared understanding of resistance risks among government regulators, growers, and other actors is critical for effective governance. Furthermore, monitoring of grower compliance with resistance management requirements, surveillance of resistance, and mechanisms to support rapid implementation of remedial actions are essential to achieve desirable outcomes. Mandated resistance management measures, strong coordination between actors, and direct linkages between the group that appraises resistance risks and growers also appear to enhance prospects for effective governance. Our analysis highlights factors that could improve current governance systems and inform other initiatives to conserve susceptibility as a contribution to the cause of public good.
Collapse
Affiliation(s)
- Yves Carrière
- Department of Entomology, University of Arizona, Tucson, USA.
| | - Zachary S Brown
- Department of Agricultural and Resource Economics, North Carolina State University, Raleigh, USA
| | | | - Govind Gujar
- South Asia Biotechnology Centre, New Delhi, India
| | - Graham Epstein
- School of Environment, Resources and Sustainability, University of Waterloo, Waterloo, Canada
| | - Celso Omoto
- Department of Entomology and Acarology, University of Sao Paulo, Sao Paulo, Brazil
| | - Nicholas P Storer
- Corteva AgriscienceTM, Agriculture Division of DowDuPont, Wilmington, USA
| | | | - Peter Søgaard Jørgensen
- Global Economic Dynamics and the Biosphere, Royal Swedish Academy of Sciences, Lilla Frescativägen 4a, 10405, Stockholm, Sweden
- Stockholm Resilience Centre, Stockholm University, Kräftriket 2B, 10691, Stockholm, Sweden
| | - Scott P Carroll
- Department of Entomology and Nematology, University of California at Davis, Davis, USA
| |
Collapse
|
4
|
Carrière Y, Williams JL, Crowder DW, Tabashnik BE. Genotype-specific fitness cost of resistance to Bt toxin Cry1Ac in pink bollworm. PEST MANAGEMENT SCIENCE 2018; 74:2496-2503. [PMID: 29604164 DOI: 10.1002/ps.4928] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/28/2018] [Accepted: 03/29/2018] [Indexed: 05/29/2023]
Abstract
BACKGROUND To improve resistance management strategies for Bacillus thuringiensis (Bt) crops, a better understanding of the relative fitness of pest genotypes with resistance alleles in the absence of Bt toxins is needed. Here, we evaluated the impact of costs of resistance to Bt toxin Cry1Ac on the relative fitness of specific pink bollworm (Pectinophora gossypiella) genotypes. We created two heterogeneous strains with an intermediate frequency of mutant cadherin alleles linked with resistance to Cry1Ac, reared the strains on diet without Bt and tracked the decline in frequency of resistant genotypes for 15-30 generations using polymerase chain reaction amplification. We used a population genetics model and sensitivity analyses to estimate the relative fitness of resistant genotypes. RESULTS Costs were completely recessive in one strain and almost completely recessive in the other. Estimates of the decline in relative fitness of the resistant homozygotes fed on a diet without Bt were 14-22% in one strain and 21-36% in the other. CONCLUSION Our genotype-specific cost estimates and the results of studies discussed herein indicate that costs associated with resistance to Bt are often large enough to significantly delay the evolution of resistance to pyramided Bt crops in pests with recessive inheritance of resistance. © 2018 Society of Chemical Industry.
Collapse
Affiliation(s)
- Yves Carrière
- Department of Entomology, University of Arizona, Tucson, USA
| | | | - David W Crowder
- Department of Entomology, Washington State University, Pullman, USA
| | | |
Collapse
|
5
|
Milonas P, Gogou C, Papadopoulou A, Fountas S, Liakos V, Papadopoulos NT. Spatio-Temporal Distribution of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) and Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) in a Cotton Production Area. NEOTROPICAL ENTOMOLOGY 2016; 45:240-251. [PMID: 27008478 DOI: 10.1007/s13744-015-0358-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 12/03/2015] [Indexed: 06/05/2023]
Abstract
Helicoverpa armigera (Hübner) and Pectinophora gossypiella (Saunders) are major pests of cotton in Greece and elsewhere. Analysing male captures in pheromone traps over two seasons, in two cotton producing sites in central Greece, the spatial and temporal variation in population dynamics were examined. In 2007, captures of male H. armigera increased in late July and maintained at high levels for 1 month and declined at the end of August. For P. gossypiella, male captures remained at low levels during summer, increased late in August, peaked at mid of September and declined toward the end of the season. In 2008, trap captures of both species increased sharply by the end of June and remained at relatively high levels until August and September for P. gossypiella and H. armigera, respectively. Spatial analysis produced a spatial trend map over space, a temporal stability map over time and a spatial and temporal trend map for both species, which could lead in separating the field into management zones, and direct control to areas that exhibit high densities of the pest population and are stable over time.
Collapse
Affiliation(s)
- P Milonas
- Dept of Entomology, Benaki Phytopathological Institute, Kifisia, Greece
| | - C Gogou
- Lab of Entomology and Agricultural Zoology, Univ of Thessaly, N. Ionia, Volos, Greece
| | - A Papadopoulou
- Lab of Entomology and Agricultural Zoology, Univ of Thessaly, N. Ionia, Volos, Greece
| | - S Fountas
- Lab of Farm Mechanization, Univ of Thessaly, N. Ionia, Greece
| | - V Liakos
- Lab of Farm Mechanization, Univ of Thessaly, N. Ionia, Greece
| | - N T Papadopoulos
- Lab of Entomology and Agricultural Zoology, Univ of Thessaly, N. Ionia, Volos, Greece.
| |
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
|
8
|
Tabashnik BE, Morin S, Unnithan GC, Yelich AJ, Ellers-Kirk C, Harpold VS, Sisterson MS, Ellsworth PC, Dennehy TJ, Antilla L, Liesner L, Whitlow M, Staten RT, Fabrick JA, Li X, Carrière Y. Sustained susceptibility of pink bollworm to Bt cotton in the United States. GM CROPS & FOOD 2014; 3:194-200. [DOI: 10.4161/gmcr.20329] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
9
|
Alvi AHK, Sayyed AH, Naeem M, Ali M. Field evolved resistance in Helicoverpa armigera (Lepidoptera: Noctuidae) to Bacillus thuringiensis toxin Cry1Ac in Pakistan. PLoS One 2012; 7:e47309. [PMID: 23077589 PMCID: PMC3471837 DOI: 10.1371/journal.pone.0047309] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 09/11/2012] [Indexed: 11/19/2022] Open
Abstract
Helicoverpa armigera (Hübner) is one of the most destructive pests of several field and vegetable crops, with indiscriminate use of insecticides contributing to multiple instances of resistance. In the present study we assessed whether H. armigera had developed resistance to Bt cotton and compared the results with several conventional insecticides. Furthermore, the genetics of resistance was also investigated to determine the inheritance to Cry1Ac resistance. To investigate the development of resistance to Bt cotton, and selected foliar insecticides, H. armigera populations were sampled in 2010 and 2011 in several cotton production regions in Pakistan. The resistance ratios (RR) for Cry1Ac, chlorpyrifos, profenofos, cypermethrin, spinosad, indoxacarb, abamectin and deltamethrin were 580-fold, 320-, 1110-, 1950-, 200-, 380, 690, and 40-fold, respectively, compared with the laboratory susceptible (Lab-PK) population. Selection of the field collected population with Cry1Ac in 2010 for five generations increased RR to 5440-fold. The selection also increased RR for deltamethrin, chlorpyrifos, profenofos, cypermethrin, spinosad, indoxacarb, abamectin to 125-folds, 650-, 2840-, 9830-, 370-, 3090-, 1330-fold. The estimated LC(50s) for reciprocal crosses were 105 µg/ml (Cry1Ac-SEL female × Lab-PK male) and 81 g µg/ml (Lab-PK female × Cry1Ac-SEL male) suggesting that the resistance to Cry1Ac was autosomal; the degree of dominance (D(LC)) was 0.60 and 0.57 respectively. Mixing of enzyme inhibitors significantly decreased resistance to Cry1Ac suggesting that the resistance to Cry1Ac and other insecticides tested in the present study was primarily metabolic. Resistance to Cry1Ac was probably due to a single but unstable factor suggesting that crop rotation with non-Bt cotton or other crops could reduce the selection pressure for H. armigera and improve the sustainability of Bt cotton.
Collapse
Affiliation(s)
- Anwaar H. K. Alvi
- Department of Entomology, PMAS Arid Agriculture University, Rawalpindi, Pakistan
- Institute of Molecular Biology & Biotechnology, Bahauddin Zakariya University, Multan, Pakistan
| | - Ali H. Sayyed
- Institute of Molecular Biology & Biotechnology, Bahauddin Zakariya University, Multan, Pakistan
- * E-mail:
| | - Muhammad Naeem
- Department of Entomology, PMAS Arid Agriculture University, Rawalpindi, Pakistan
| | - Muhammad Ali
- Institute of Molecular Biology & Biotechnology, Bahauddin Zakariya University, Multan, Pakistan
| |
Collapse
|
10
|
Gassmann AJ, Hannon ER, Sisterson MS, Stock SP, Carrière Y, Tabashnik BE. Effects of entomopathogenic nematodes on evolution of pink bollworm resistance to Bacillus thuringiensis toxin Cry1Ac. JOURNAL OF ECONOMIC ENTOMOLOGY 2012; 105:994-1005. [PMID: 22812141 DOI: 10.1603/ec11376] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The evolution of resistance by pests can reduce the efficacy of transgenic crops that produce insecticidal toxins from Bacillus thuringiensis (Bt). However, fitness costs may act to delay pest resistance to Bt toxins. Meta-analysis of results from four previous studies revealed that the entomopathogenic nematode Steinernema riobrave (Rhabditida: Steinernematidae) imposed a 20% fitness cost for larvae of pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), that were homozygous for resistance to Bt toxin Cry1Ac, but no significant fitness cost was detected for heterozygotes. We conducted greenhouse and laboratory selection experiments to determine whether S. riobrave would delay the evolution of pink bollworm resistance to Cry1Ac. We mimicked the high dose/refuge scenario in the greenhouse with Bt cotton (Gossypium hirsutum L.) plants and refuges of non-Bt cotton plants, and in the laboratory with diet containing Cry1Ac and refuges of untreated diet. In both experiments, half of the replicates were exposed to S. riobrave and half were not. In the greenhouse, S. riobrave did not delay resistance. In the laboratory, S. riobrave delayed resistance after two generations but not after four generations. Simulation modeling showed that an initial resistance allele frequency > 0.015 and population bottlenecks can diminish or eliminate the resistance-delaying effects of fitness costs. We hypothesize that these factors may have reduced the resistance-delaying effects of S. riobrave in the selection experiments. The experimental and modeling results suggest that entomopathogenic nematodes could slow the evolution of pest resistance to Bt crops, but only under some conditions.
Collapse
Affiliation(s)
- Aaron J Gassmann
- Department of Entomology, Iowa State University, Ames, IA 50011, USA.
| | | | | | | | | | | |
Collapse
|
11
|
Tabashnik BE, Gould F. Delaying corn rootworm resistance to Bt corn. JOURNAL OF ECONOMIC ENTOMOLOGY 2012; 105:767-76. [PMID: 22812111 DOI: 10.1603/ec12080] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Transgenic crops producing Bacillus thuringiensis (Bt) toxins for insect control have been successful, but their efficacy is reduced when pests evolve resistance. To delay pest resistance to Bt crops, the U.S. Environmental Protection Agency (EPA) has required refuges of host plants that do not produce Bt toxins to promote survival of susceptible pests. Such refuges are expected to be most effective if the Bt plants deliver a dose of toxin high enough to kill nearly all hybrid progeny produced by matings between resistant and susceptible pests. In 2003, the EPA first registered corn, Zea mays L., producing a Bt toxin (Cry3Bb1) that kills western corn rootworm, Diabrotica virgifera virgifera LeConte, one of the most economically important crop pests in the United States. The EPA requires minimum refuges of 20% for Cry3Bb1 corn and 5% for corn producing two Bt toxins active against corn rootworms. We conclude that the current refuge requirements are not adequate, because Bt corn hybrids active against corn rootworms do not meet the high-dose standard, and western corn rootworm has rapidly evolved resistance to Cry3Bb1 corn in the laboratory, greenhouse, and field. Accordingly, we recommend increasing the minimum refuge for Bt corn targeting corn rootworms to 50% for plants producing one toxin active against these pests and to 20% for plants producing two toxins active against these pests. Increasing the minimum refuge percentage can help to delay pest resistance, encourage integrated pest management, and promote more sustainable crop protection.
Collapse
Affiliation(s)
- Bruce E Tabashnik
- Department of Entomology, University of Arizona, Tucson, AZ 85721, USA.
| | | |
Collapse
|
12
|
Showalter AM, Heuberger S, Tabashnik BE, Carrière Y. A primer for using transgenic insecticidal cotton in developing countries. JOURNAL OF INSECT SCIENCE (ONLINE) 2009; 9:22. [PMID: 19613464 PMCID: PMC3011844 DOI: 10.1673/031.009.2201] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Accepted: 06/06/2008] [Indexed: 05/03/2023]
Abstract
Many developing countries face the decision of whether to approve the testing and commercial use of insecticidal transgenic cotton and the task of developing adequate regulations for its use. In this review, we outline concepts and provide information to assist farmers, regulators and scientists in making decisions concerning this technology. We address seven critical topics: 1) molecular and breeding techniques used for the development of transgenic cotton cultivars, 2) properties of transgenic cotton cultivars and their efficacy against major insect pests, 3) agronomic performance of transgenic cotton in developing countries, 4) factors affecting transgene expression, 5) impact of gene flow between transgenic and non-transgenic cotton, 6) non-target effects of transgenic cotton, and 7) management of pest resistance to transgenic cotton.
Collapse
Affiliation(s)
| | | | | | - Yves Carrière
- Department of Entomology, University of Arizona, Tucson AZ
| |
Collapse
|
13
|
|
14
|
Baker GH, Tann CR, Fitt GP. Production of Helicoverpa spp. (Lepidoptera, Noctuidae) from different refuge crops to accompany transgenic cotton plantings in eastern Australia. ACTA ACUST UNITED AC 2008. [DOI: 10.1071/ar07421] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The adoption of transgenic (Bt) cotton varieties has markedly reduced feeding damage by noctuid pests, Helicoverpa armigera and H. punctigera, in Australian cotton crops. However, the potential for Bt resistance to evolve within these insect pests is a major concern. To reduce the likelihood of Bt resistance occurring, it is mandatory for growers of Bt cotton to also grow refuge crops which produce large numbers of Bt-susceptible moths. We present here findings from a series of field studies which sought to identify the relative Helicoverpa productivity of different refuge crop options. The abundance of Helicoverpa pupae (during the cotton season) was compared under crops of Ingard® (transgenic, single Bt gene) cotton, sprayed conventional cotton, and various unsprayed refuge crops (cotton, sorghum, maize, pigeon pea) from 1996 to 2003 in the major cotton-producing regions of northern New South Wales, plus St George and Dirranbandi in southern Queensland. Unsprayed, conventional cotton was used as the ‘control’ refuge in these studies. Productivity of adult Helicoverpa was estimated by surveying for pupae and discounting those that were parasitised and dead. Some supplementary experiments were also conducted to evaluate specific issues, in particular the value of additional refuge crops sown late in 2000–01 (due to accidental over-planting of Ingard® cotton that year) and the potential productivity of mixed plantings of various refuge crops which individually flowered at different times throughout the cotton season. Unsprayed refuges generally produced many more pupae than sprayed, conventional cotton and Ingard® cotton. Overall, pigeon pea, which has the advantage of prolonged flowering and thus on-going attractiveness to Helicoverpa, was the most reliable and productive refuge option, producing about twice as many pupae as unsprayed cotton. The seed mix refuge is perhaps a viable alternative option, although logistically more difficult for growers to adopt. Laboratory rearing of live pupae until moth emergence indicated that parasitism can be a substantial source of mortality in some refuge crops, especially sorghum. The most common parasitoid of Helicoverpa pupae was the ichneumonid wasp, Heteropelma scaposum. Such parasitism can greatly reduce productivity of adult Helicoverpa from refuges and needs to be taken into account when assessing relative refuge ‘value’, although such refuges will obviously contribute to the abundance of these beneficial species across the landscape.
Collapse
|
15
|
Gutierrez AP, D’Oultremont T, Ellis C, Ponti L. Climatic limits of pink bollworm in Arizona and California: effects of climate warming. ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 2006. [DOI: 10.1016/j.actao.2006.06.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
16
|
Parnell S, van den Bosch F, Gilligan CA. Large-scale fungicide spray heterogeneity and the regional spread of resistant pathogen strains. PHYTOPATHOLOGY 2006; 96:549-555. [PMID: 18944316 DOI: 10.1094/phyto-96-0549] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT Most models for the spread of fungicide resistance in plant pathogens are focused on within-field dynamics, yet regional invasion depends upon the interactions between field populations. Here, we use a spatially implicit metapopulation model to describe the dynamics of regional spread, in which subpopulations correspond to single fields. We show that the criterion for the regional invasion of pathogens between fields differs from that for invasion within fields. That is, the ability of a fungicide-resistant strain of a pathogen to invade a field population does not necessarily imply an ability to spread through many fields at the regional scale. This depends upon an interaction between the fraction of fields that is sprayed and the reproductive capacity of the pathogen. This result is of practical significance and indicates that resistance management strategies which currently target within-field processes, such as the use of mixtures and alternations of fungicides, may be more effective if between-field processes also were targeted; for example, through the restricted deployment of fungicides over large areas. We also show that the fraction of disease-free fields is maximized when the proportion of fields that is sprayed is just below the threshold for invasion of the resistant strain.
Collapse
|
17
|
Gutierrez AP, Adamczyk JJ, Ponsard S, Ellis C. Physiologically based demographics of Bt cotton–pest interactions. Ecol Modell 2006. [DOI: 10.1016/j.ecolmodel.2005.06.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
18
|
Carrière Y, Ellers-Kirk C, Kumar K, Heuberger S, Whitlow M, Antilla L, Dennehy TJ, Tabashnik BE. Long-term evaluation of compliance with refuge requirements for Bt cotton. PEST MANAGEMENT SCIENCE 2005; 61:327-330. [PMID: 15714465 DOI: 10.1002/ps.1039] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The success of the refuge strategy for delaying pest resistance to Bt crops depends on compliance by farmers. However, the accuracy of previous estimates of compliance has been questioned. We have applied a novel approach based on the use of Geographical Information System (GIS) technology to measure compliance with refuge requirements for Bt cotton in six Arizona regions from 1998 to 2003. Although compliance varied among regions, overall compliance was above 88% in five of six years. With the cooperation of farmers, our approach allows precise and economical assessment of compliance with the refuge strategy.
Collapse
Affiliation(s)
- Yves Carrière
- Department of Entomology, 410 Forbes Building, The University of Arizona, Tucson, AZ 85721, USA.
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Meng F, Shen J, Zhou W, Cen H. Long-term selection for resistance to transgenic cotton expressing Bacillus thuringiensis toxin in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). PEST MANAGEMENT SCIENCE 2004; 60:167-172. [PMID: 14971684 DOI: 10.1002/ps.806] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Selection experiments for resistance to transgenic Bt cotton expressing Cry1Ac toxin in Helicoverpa armigera (Hübner) were conducted using a leaf-feeding method with 42 selection episodes over 45 generations. The cotton bollworm developed resistance to transgenic Bt cotton after 12 generations (F12) of selection. The survival rate of F12 neonates feeding on leaves of seedling stage for 4 days and boll-opening stage for 5 days of R19 line were ca 34 and 72%, respectively, compared with ca 0 and 40% for a non-selected sister strain (NYCS), but lower than or similar to that of F12 feeding on leaves of non-Bt cotton, Sumian 12 (ca 87 or 76%). Resistance to B thuringiensis HD-1 Dipel in neonates (F12) was ca 6-fold. After 42 generations of selection, the strain developed a very high level of resistance to Cry1Ac protoxin, 210 g kg(-1) MVPII wettable powder and 200 g litre(-1) MVPII liquid formulation, the resistance ratios being 1680-, 1780- and ca 1200-fold, respectively, compared with a laboratory susceptible strain (HZS). When compared with the non-selected NYCS, the resistance ratios to the above toxins were ca 540-, 580- and 510-fold, respectively, but to Dipel only ca 16-fold. The results indicated that it is very important to develop and implement effective resistance-management strategies and to detect early resistance to Bt cotton in field populations.
Collapse
Affiliation(s)
- Fengxia Meng
- Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, China National Centre for Monitoring Pesticide Resistance, Department of Pesticide Science, Nanjing Agricultural University, Nanjing 210095, China
| | | | | | | |
Collapse
|
20
|
Abstract
Increasing interest in the responsible management of technology in the industrial and agricultural sectors of the economy has been met thorough the development of broadly applicable tools to assess the "sustainability" of new technologies. An arena ripe for application of such analysis is the deployment of transgenic crops. The new transgenic pesticidal or plant-incorporated protectant (PIP) crops have seen widespread application in the United States based on the features of higher yield, lower applications of insecticides, and control of mycotoxin content. However, open rejection of these new crops in Europe and in other countries has been a surprising message and has limited their worldwide acceptance. The US Environmental Protection Agency's (USEPA) Office of Pesticide Programs (OPP) has worked on the development and analysis of insect resistance management (IRM) strategies and has mandated specific IRM requirements for Bacillus thuringiensis (Bt) crops since 1995 under the Food, Fungicide, Insecticide, and Rodenticide Act. Improvement of data quality and sustainability of IRM strategies have been targeted in an ongoing partnership between the USEPA Office of Research and Development and the Office of Pesticide Programs that will further enhance the agency's ability to develop sustainable insect resistance management strategies for transgenic field corn (Bt corn) producing B. thuringiensis (Bt) insecticidal proteins.
Collapse
Affiliation(s)
- John A Glaser
- United States Environmental Protection Agency, Office of Research & Development, National Risk Management Research Laboratory, Sustainable Technology Division, 26 W King Dr., Cincinnati, OH 45268, USA.
| | | |
Collapse
|
21
|
González-Cabrera J, Escriche B, Tabashnik BE, Ferré J. Binding of Bacillus thuringiensis toxins in resistant and susceptible strains of pink bollworm (Pectinophora gossypiella). INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2003; 33:929-935. [PMID: 12915184 DOI: 10.1016/s0965-1748(03)00099-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Evolution of resistance by pests could cut short the success of transgenic plants producing toxins from Bacillus thuringiensis, such as Bt cotton. The most common mechanism of insect resistance to B. thuringiensis is reduced binding of toxins to target sites in the brush border membrane of the larval midgut. We compared toxin binding in resistant and susceptible strains of Pectinophora gossypiella, a major pest of cotton worldwide. Using Cry1Ab and Cry1Ac labeled with (125)I and brush border membrane vesicles (BBMV), competition experiments were performed with unlabeled Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ba, Cry1Ca, Cry1Ja, Cry2Aa, and Cry9Ca. In the susceptible strain, Cry1Aa, Cry1Ab, Cry1Ac, and Cry1Ja bound to a common binding site that was not shared by the other toxins tested. Reciprocal competition experiments with Cry1Ab, Cry1Ac, and Cry1Ja showed that these toxins do not bind to any additional binding sites. In the resistant strain, binding of (125)I-Cry1Ac was not significantly affected; however, (125)I-Cry1Ab did not bind to the BBMV. This result, along with previous data from this strain, shows that the resistance fits the "mode 1" pattern of resistance described previously in Plutella xylostella, Plodia interpunctella, and Heliothis virescens.
Collapse
Affiliation(s)
- Joel González-Cabrera
- Departamento de Genética, Facultad de CC. Biológicas, Universidad de Valencia, , 46100-Burjassot, Valencia, Spain
| | | | | | | |
Collapse
|
22
|
Carrière Y, Ellers-Kirk C, Sisterson M, Antilla L, Whitlow M, Dennehy TJ, Tabashnik BE. Long-term regional suppression of pink bollworm by Bacillus thuringiensis cotton. Proc Natl Acad Sci U S A 2003; 100:1519-23. [PMID: 12571355 PMCID: PMC149864 DOI: 10.1073/pnas.0436708100] [Citation(s) in RCA: 245] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2002] [Indexed: 11/18/2022] Open
Abstract
Despite the potentially profound impact of genetically modified crops on agriculture and the environment, we know little about their long-term effects. Transgenic crops that produce toxins from Bacillus thuringiensis (Bt) to control insects are grown widely, but rapid evolution of resistance by pests could nullify their benefits. Here, we present theoretical analyses showing that long-term suppression of pest populations is governed by interactions among reproductive rate, dispersal propensity, and regional abundance of a Bt crop. Supporting this theory, a 10-year study in 15 regions across Arizona shows that Bt cotton suppressed a major pest, pink bollworm (Pectinophora gossypiella), independent of demographic effects of weather and variation among regions. Pink bollworm population density declined only in regions where Bt cotton was abundant. Such long-term suppression has not been observed with insecticide sprays, showing that transgenic crops open new avenues for pest control. The debate about putative benefits of Bt crops has focused primarily on short-term decreases in insecticide use. The present findings suggest that long-term regional pest suppression after deployment of Bt crops may also contribute to reducing the need for insecticide sprays.
Collapse
Affiliation(s)
- Yves Carrière
- Department of Entomology, University of Arizona, Tucson, AZ 85721, USA.
| | | | | | | | | | | | | |
Collapse
|
23
|
Tabashnik BE, Dennehy TJ, Sims MA, Larkin K, Head GP, Moar WJ, Carrière Y. Control of resistant pink bollworm (Pectinophora gossypiella) by transgenic cotton that produces Bacillus thuringiensis toxin Cry2Ab. Appl Environ Microbiol 2002; 68:3790-4. [PMID: 12147473 PMCID: PMC124036 DOI: 10.1128/aem.68.8.3790-3794.2002] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Crops genetically engineered to produce Bacillus thuringiensis toxins for insect control can reduce use of conventional insecticides, but insect resistance could limit the success of this technology. The first generation of transgenic cotton with B. thuringiensis produces a single toxin, Cry1Ac, that is highly effective against susceptible larvae of pink bollworm (Pectinophora gossypiella), a major cotton pest. To counter potential problems with resistance, second-generation transgenic cotton that produces B. thuringiensis toxin Cry2Ab alone or in combination with Cry1Ac has been developed. In greenhouse bioassays, a pink bollworm strain selected in the laboratory for resistance to Cry1Ac survived equally well on transgenic cotton with Cry1Ac and on cotton without Cry1Ac. In contrast, Cry1Ac-resistant pink bollworm had little or no survival on second-generation transgenic cotton with Cry2Ab alone or with Cry1Ac plus Cry2Ab. Artificial diet bioassays showed that resistance to Cry1Ac did not confer strong cross-resistance to Cry2Aa. Strains with >90% larval survival on diet with 10 microg of Cry1Ac per ml showed 0% survival on diet with 3.2 or 10 microg of Cry2Aa per ml. However, the average survival of larvae fed a diet with 1 microg of Cry2Aa per ml was higher for Cry1Ac-resistant strains (2 to 10%) than for susceptible strains (0%). If plants with Cry1Ac plus Cry2Ab are deployed while genes that confer resistance to each of these toxins are rare, and if the inheritance of resistance to both toxins is recessive, the efficacy of transgenic cotton might be greatly extended.
Collapse
Affiliation(s)
- Bruce E Tabashnik
- Department of Entomology, University of Arizona, Tucson, Arizona 85721, USA.
| | | | | | | | | | | | | |
Collapse
|
24
|
Abstract
In recent years, there has been increasing interest in how changes in agricultural practice associated with the introduction of particular genetically modified (GM) crops might indirectly impact the environment. There is also interest in any effects that might be associated with recombinant and novel combinations of DNA passing into the environment, and the possibility that they may be taken up by microorganisms or other live biological material. From the current state of knowledge, the impact of free DNA of transgenic origin is likely to be negligible compared with the large amount of total free DNA. We can find no compelling scientific arguments to demonstrate that GM crops are innately different from non-GM crops. The kinds of potential impacts of GM crops fall into classes familiar from the cultivation of non-GM crops (e.g., invasiveness, weediness, toxicity, or biodiversity). It is likely, however, that the novelty of some of the products of GM crop improvement will present new challenges and perhaps opportunities to manage particular crops in creative ways.
Collapse
Affiliation(s)
- Philip J Dale
- John Innes Centre, Colney Lane, Norwich NR4 7UH, UK.
| | | | | |
Collapse
|
25
|
Shelton AM, Zhao JZ, Roush RT. Economic, ecological, food safety, and social consequences of the deployment of bt transgenic plants. ANNUAL REVIEW OF ENTOMOLOGY 2002; 47:845-81. [PMID: 11729093 DOI: 10.1146/annurev.ento.47.091201.145309] [Citation(s) in RCA: 282] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Transgenic plants expressing insecticidal proteins from the bacterium, Bacillus thuringiensis (Bt), are revolutionizing agriculture. Bt, which had limited use as a foliar insecticide, has become a major insecticide because genes that produce Bt toxins have been engineered into major crops grown on 11.4 million ha worldwide in 2000. Based on the data collected to date, generally these crops have shown positive economic benefits to growers and reduced the use of other insecticides. The potential ecological and human health consequences of Bt plants, including effects on nontarget organisms, food safety, and the development of resistant insect populations, are being compared for Bt plants and alternative insect management strategies. Scientists do not have full knowledge of the risks and benefits of any insect management strategies. Bt plants were deployed with the expectation that the risks would be lower than current or alternative technologies and that the benefits would be greater. Based on the data to date, these expectations seem valid.
Collapse
Affiliation(s)
- A M Shelton
- Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, New York 14456, USA.
| | | | | |
Collapse
|
26
|
Carrière Y, Ellers-Kirk C, Pedersen B, Haller S, Antilla L. Predicting spring moth emergence in the pink bollworm (Lepidoptera: Gelechiidae): implications for managing resistance to transgenic cotton. JOURNAL OF ECONOMIC ENTOMOLOGY 2001; 94:1012-1021. [PMID: 11681660 DOI: 10.1603/0022-0493-94.5.1012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Cultural control methods have been central in the southwestern United States for reducing pink bollworm, Pectinophora gossypiella (Saunders), damage to cotton. Nevertheless, it is not clear at present how such methods could be integrated within the novel pest management framework allowed by introduction of cotton producing a toxin from Bacillus thuringiensis (Bt) for pink bollworm control. Using statewide pheromone trapping and climatic data in conjunction with deterministic simulation models, we investigated whether manipulation of cotton planting date and use of other cultural control methods could represent valuable tactics for control of the pink bollworm in Arizona. Accumulation of heat units from one January accurately predicted the rate of pink bollworm emergence from diapause in 15 cotton-producing regions. Significant variation in rate of emergence from diapause was present among regions, with earlier emergence at higher altitudes. Most adults emerge from diapause too early to reproduce successfully on cotton, a phenomenon known as suicidal emergence. A method for prediction of the fraction of suicidal emergence resulting from adoption of a given cotton planting date is presented. Results from simulation models suggest that manipulation of planting date and implementation of other control cultural methods reduce the rate of application of insecticides and delay the evolution of resistance to Bt cotton in the pink bollworm.
Collapse
Affiliation(s)
- Y Carrière
- Department of Entomology, University of Arizona, Tucson 85721, USA.
| | | | | | | | | |
Collapse
|
27
|
Abstract
The refuge-high-dose strategy for delaying insect adaptation to transgenic plants produces non-transgenic plants that enable survival of susceptible individuals. Previous theoretical work has suggested three requirements for success of the refuge-high-dose strategy: a low initial frequency of the resistance allele, extensive mating between resistant and susceptible adults and recessive inheritance of resistance. In order to understand an observed decrease in resistance frequency and improve the potential for managing resistance better, we used analytical and simulation models for exploring the conditions that prevent or reverse the evolution of resistance, even when resistance is not rare initially. Assuming random mating and recessive or nearly recessive inheritance of resistance, the factors favouring reversal of resistance are non-recessive costs of resistance, low initial resistance allele frequency, large refuges, incomplete resistance and density-independent population growth in refuges.
Collapse
Affiliation(s)
- Y Carrière
- Department of Entomology, The University of Arizona, 410 Forbes Building, Tucson, AZ 85721, USA.
| | | |
Collapse
|
28
|
|