The Present and Future Role of Insect-Resistant Genetically Modified Cotton in IPM

Naranjo, Steven E.; Ruberson, John R.; Sharma, H. C.; Wilson, Lewis; Wu, Kongming

doi:10.1007/978-1-4020-8373-0_6

Cited by 65 publications

(69 citation statements)

References 82 publications

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“…and Pectinophora gossypiella (Saunders)]. These B. thuringiensis-transgenic cotton plants are highly resistant to damage by lepidopteran pests, and consequently, the application of chemical insecticides has been greatly reduced (12,32). This makes Bt cotton a valuable component of integrated pest management programs, with many environmental, economic, and health benefits (34,35).…”

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confidence: 99%

Effectiveness of Bacillus thuringiensis -Transgenic Chickpeas and the Entomopathogenic Fungus Metarhizium anisopliae in Controlling Helicoverpa armigera (Lepidoptera: Noctuidae)

Lawo

Mahon

Milner

et al. 2008

Appl Environ Microbiol

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The use of genetically modified (Bt) crops expressing lepidopteran-specific Cry proteins derived from the soil bacterium Bacillus thuringiensis is an effective method to control the polyphagous pest Helicoverpa armigera. As H. armigera potentially develops resistance to Cry proteins, Bt crops should be regarded as one tool in integrated pest management. Therefore, they should be compatible with biological control. Bioassays were conducted to understand the interactions between a Cry2Aa-expressing chickpea line, either a susceptible or a Cry2A-resistant H. armigera strain, and the entomopathogenic fungus Metarhizium anisopliae. In a first concentration-response assay, Cry2A-resistant larvae were more tolerant of M. anisopliae than susceptible larvae, while in a second bioassay, the fungus caused similar mortalities in the two strains fed control chickpea leaves. Thus, resistance to Cry2A did not cause any fitness costs that became visible as increased susceptibility to the fungus. On Bt chickpea leaves, susceptible H. armigera larvae were more sensitive to M. anisopliae than on control leaves. It appeared that sublethal damage induced by the B. thuringiensis toxin enhanced the effectiveness of M. anisopliae. For Cry2A-resistant larvae, the mortalities caused by the fungus were similar when they were fed either food source. To examine which strain would be more likely to be exposed to the fungus, their movements on control and Bt chickpea plants were compared. Movement did not appear to differ among larvae on Bt or conventional chickpeas, as indicated by the number of leaflets damaged per leaf. The findings suggest that Bt chickpeas and M. anisopliae are compatible to control H. armigera.

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confidence: 99%

Effectiveness of Bacillus thuringiensis -Transgenic Chickpeas and the Entomopathogenic Fungus Metarhizium anisopliae in Controlling Helicoverpa armigera (Lepidoptera: Noctuidae)

Lawo

Mahon

Milner

et al. 2008

Appl Environ Microbiol

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“…In India, most of the predators of T. tabaci are generalists that rely on T. tabaci as a food source early in the season, the time when Cry protein expression in the cotton plant is high (Kranthi et al 2005, Bakhsh et al 2012. Similar nontarget pest issues with different pest species have been observed in China, Australia, and the United States (Naranjo et al 2008).…”

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confidence: 92%

“…Cotton is attacked by a large complex of insect pests but the most damaging is the bollworm complex, primarily Helicoverpa zea (Boddie), Helicoverpa armigera (Hü bner), Helicoverpa punctigera (Wallengren), Heliothis virescens (Fabricius) (Lepidoptera: Noctuiidae), and Pectinophora gossypiella Saunders (Lepidoptera: Gelechiidae). The Cry proteins produced in Bt cotton target these and additional Lepidoptera but do not affect a number of other cotton pest species (Naranjo et al 2008).…”

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confidence: 99%

“…Initially, Bt cotton varieties producing only a single Cry protein were cultivated, but these have largely been replaced in most areas of the world by cotton producing two Cry proteins, such as Bollgard-II (BG-II), producing Cry1Ac and Cry2Ab (Naranjo et al 2008). The Cry proteins in Bt cotton are produced throughout the entire growing season, and so target and nontarget arthropods have ample opportunity for exposure to these proteins.…”

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confidence: 99%

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Effects of Bt Cotton on <I>Thrips tabaci</I> (Thysanoptera: Thripidae) and Its Predator, <I>Orius insidiosus</I> (Hemiptera: Anthocoridae)

Kumar¹,

Tian²,

Naranjo³

et al. 2014

j econ entomol

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Laboratory studies were conducted to investigate tritrophic transfer of insecticidal Cry proteins from transgenic cotton to an herbivore and its predator, and to examine effects of these proteins on the predatorÕs development, survival, and reproduction. Cry1Ac and Cry2Ab proteins from the bacterium Bacillus thuringiensis (Bt) produced in Bollgard-II (BG-II, Event 15985) cotton plants were acquired by Thrips tabaci Lindeman (Thysanoptera: Thripidae), an important sucking pest of cotton, and its generalist predator, Orius insidiosus (Say) (Hemiptera: Anthocoridae). The average protein titers in BG-II cotton leaves were 1,256 and 43,637 ng Cry1Ac and Cry2Ab per gram fresh leaf tissue, respectively. At the second trophic level, larvae of T. tabaci reared on BG-II cotton for 48 Ð96 h had 22.1 and 2.1% of the Cry1Ac and Cry2Ab levels expressed in leaves, respectively. At the third trophic level, O. insidiosus that fed on T. tabaci larvae had 4.4 and 0.3% of the Cry1Ac and Cry2Ab protein levels, respectively, expressed in BG-II plants. O. insidiosus survivorship, time of nymphal development, adult weight, preoviposition and postoviposition periods, fecundity, and adult longevity were not adversely affected owing to consumption of T. tabaci larvae that had fed on BG-II cotton compared with non-Bt cotton. Our results indicate that O. insidiosus, a common predator of T. tabaci, is not harmed by BG-II cotton when exposed to Bt proteins through its prey. Thus, O. insidiosus can continue to provide important biological control services in the cotton ecosystem when BG-II cotton is used to control primary lepidopteran pests.

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“…Second, reduced insecticide sprays against Helicoverpa spp. allowed some pests, formerly coincidentally controlled by these sprays and not affected by the Bt proteins, to increase to damaging levels (Lei et al 2003;Naranjo et al 2008). The most important of these emergent pests have been the green mirid (Creontiades dilutus) and the green vegetable bug (Nezara viridula).…”

Section: Introductionmentioning

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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The Present and Future Role of Insect-Resistant Genetically Modified Cotton in IPM

Cited by 65 publications

References 82 publications

Effectiveness of Bacillus thuringiensis -Transgenic Chickpeas and the Entomopathogenic Fungus Metarhizium anisopliae in Controlling Helicoverpa armigera (Lepidoptera: Noctuidae)

Effectiveness of Bacillus thuringiensis -Transgenic Chickpeas and the Entomopathogenic Fungus Metarhizium anisopliae in Controlling Helicoverpa armigera (Lepidoptera: Noctuidae)

Effects of Bt Cotton on <I>Thrips tabaci</I> (Thysanoptera: Thripidae) and Its Predator, <I>Orius insidiosus</I> (Hemiptera: Anthocoridae)

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

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