Widespread adoption of Bt cotton and insecticide decrease promotes biocontrol services

Lu, Yanhui; Wu, Kongming; Jiang, Yuying; Guo, Yong; Desneux, Nicolas

doi:10.1038/nature11153

Cited by 672 publications

(422 citation statements)

References 30 publications

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“…W rs = BtW rs · P Bt + RefW rs · P Ref , [3] W ss = BtW ss · P Bt + RefW ss · P Ref , [4] where P Bt is the proportion of We iterated Eq. 1 with a computer program to project changes in the r allele frequency over successive generations.…”

Section: Methodsmentioning

confidence: 99%

Hybridizing transgenic Bt cotton with non-Bt cotton counters resistance in pink bollworm

Wan

Cong

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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115

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Extensive cultivation of crops genetically engineered to produce insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) has suppressed some major pests, reduced insecticide sprays, enhanced pest control by natural enemies, and increased grower profits. However, these benefits are being eroded by evolution of resistance in pests. We report a strategy for combating resistance by crossing transgenic Bt plants with conventional non-Bt plants and then crossing the resulting first-generation (F 1 ) hybrid progeny and sowing the second-generation (F 2 ) seeds. This strategy yields a random mixture within fields of three-quarters of plants that produce Bt toxin and one-quarter that does not. We hypothesized that the non-Bt plants in this mixture promote survival of susceptible insects, thereby delaying evolution of resistance. To test this hypothesis, we compared predictions from computer modeling with data monitoring pink bollworm (Pectinophora gossypiella) resistance to Bt toxin Cry1Ac produced by transgenic cotton in an 11-y study at 17 field sites in six provinces of China. The frequency of resistant individuals in the field increased before this strategy was widely deployed and then declined after its widespread adoption boosted the percentage of non-Bt cotton plants in the region. The correspondence between the predicted and observed outcomes implies that this strategy countered evolution of resistance. Despite the increased percentage of non-Bt cotton, suppression of pink bollworm was sustained. Unlike other resistance management tactics that require regulatory intervention, growers adopted this strategy voluntarily, apparently because of advantages that may include better performance as well as lower costs for seeds and insecticides.sustainability | evolution | resistance management | genetically modified | refuge G enetically engineered crops that produce insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) have been planted globally on a cumulative total of over 732 million ha since 1996 (1). The benefits of these Bt crops include pest suppression, reduced insecticide use, enhanced biological control, and increased farmer profits (2-7). However, increasingly rapid evolution of resistance to Bt crops by pests has eroded these benefits (8-11). The main strategy for delaying pest resistance to Bt crops aims to increase the survival of susceptible insects with "refuges" of host plants that do not produce Bt toxins (9). Although refuges can delay insect adaptation to Bt crops (2, 3, 9, 12), the optimal spatial scale for planting refuges remains unresolved (13-15). Also, because refuges are often perceived to cause short-term economic sacrifices for growers, they are usually imposed by regulations.Before 2010, regulations in the United States mandated refuges of non-Bt plants in blocks consisting of separate fields, rows, or strips (14). In 2010, the regulations were modified to include mixtures of Bt and non-Bt seeds generating a random array of Bt and non-Bt plants side by side within...

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Section: Methodsmentioning

confidence: 99%

Hybridizing transgenic Bt cotton with non-Bt cotton counters resistance in pink bollworm

Wan

Cong

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

115

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“…genetically modified | sustainability C orn and cotton engineered to produce insecticidal proteins from Bacillus thuringiensis (Bt) have provided several benefits, including reduced insecticide use, regional pest suppression, protection of natural enemies, and increased or less variable yields (1)(2)(3). Evolution of resistance by pests, however, is the most serious threat to the continued efficacy of Bt crops.…”

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confidence: 99%

Potential shortfall of pyramided transgenic cotton for insect resistance management

Brévault

Heuberger

Zhang

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

149

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To delay evolution of pest resistance to transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt), the "pyramid" strategy uses plants that produce two or more toxins that kill the same pest. In the United States, this strategy has been adopted widely, with two-toxin Bt cotton replacing one-toxin Bt cotton. Although two-toxin plants are likely to be more durable than one-toxin plants, the extent of this advantage depends on several conditions. One key assumption favoring success of two-toxin plants is that they kill insects selected for resistance to one toxin, which is called "redundant killing." Here we tested this assumption for a major pest, Helicoverpa zea, on transgenic cotton producing Bt toxins Cry1Ac and Cry2Ab. Selection with Cry1Ac increased survival on two-toxin cotton, which contradicts the assumption. The concentration of Cry1Ac and Cry2Ab declined during the growing season, which would tend to exacerbate this problem. Furthermore, analysis of results from 21 selection experiments with eight species of lepidopteran pests indicates that some cross-resistance typically occurs between Cry1A and Cry2A toxins. Incorporation of empirical data into simulation models shows that the observed deviations from ideal conditions could greatly reduce the benefits of the pyramid strategy for pests like H. zea, which have inherently low susceptibility to Bt toxins and have been exposed extensively to one of the toxins in the pyramid before two-toxin plants are adopted. For such pests, the pyramid strategy could be improved by incorporating empirical data on deviations from ideal assumptions about redundant killing and cross-resistance. (Résumé d'auteur

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“…The IPM Guidelines for Cotton Production Systems emphasise conservation of beneficial species through use of the most selective control options against target pests when required . The dramatically reduced spray regime associated with Bt-cotton has led to increased survival of beneficial populations, both in Australia (Mansfield et al 2006) and in China (Lu et al 2012c). Further, recent research has also shown the value of native vegetation remnants on farms as a source of beneficial species that can migrate into cotton and other crops (e.g.…”

Section: The Role Of Beneficial Arthropodsmentioning

confidence: 99%

IPM in the transgenic era: a review of the challenges from emerging pests in Australian cotton systems

Wilson

Downes

Khan³

et al. 2013

Crop Pasture Sci.

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Abstract. The Cotton Catchment Communities Cooperative Research Centre began during a period of rapid uptake of Bollgard II ® cotton, which contains genes to express two Bt proteins that control the primary pests of cotton in Australia, Helicoverpa armigera and H. punctigera. The dramatic uptake of this technology presumably resulted in strong selection pressure for resistance in Helicoverpa spp. against the Bt proteins. The discovery of higher than expected levels of resistance in both species against one of the proteins in Bollgard II ® cotton (Cry2Ab) led to significant re-evaluation of the resistance management plan developed for this technology, which was a core area of research for the Cotton CRC. The uptake of Bollgard II ® cotton also led to a substantial decline in pesticide applications against Helicoverpa spp. (from 10-14 to 0-3 applications per season). The low spray environment allowed some pests not controlled by the Bt proteins to emerge as more significant pests, especially sucking species such as Creontiades dilutus and Nezara viridula. A range of other minor pests have also sporadically arisen as problems. Lack of knowledge and experience with these pests created uncertainty and encouraged insecticide use, which threatened to undermine the gains made with Bollgard II ® cotton. Here we chronicle the achievements of the Cotton CRC in providing the industry with new knowledge and management strategies for these pests.

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Widespread adoption of Bt cotton and insecticide decrease promotes biocontrol services

Cited by 672 publications

References 30 publications

Hybridizing transgenic Bt cotton with non-Bt cotton counters resistance in pink bollworm

Hybridizing transgenic Bt cotton with non-Bt cotton counters resistance in pink bollworm

Potential shortfall of pyramided transgenic cotton for insect resistance management

IPM in the transgenic era: a review of the challenges from emerging pests in Australian cotton systems

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