Genetically modified corn on fall armyworm and earwig populations under field conditions

Frizzas, Marina Regina; Neto, Sinval Silveira; Oliveira, Charles Martins de; Omoto, Celso

doi:10.1590/s0103-84782014000200002

Cited by 14 publications

(7 citation statements)

References 16 publications

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“…In addition, extended larval stages tend to increase the likelihood of mortality by natural enemies [ 10 , 61 – 64 ], which can delay resistance development to Bt plants when maintaining a low pest density and low crop damage [ 65 ]. In fact, damage by fall armyworm seem to be minimized when Bt maize is concurrently used with biological control [ 66 , 67 ], especially small predatory bugs, which are found abundantly in maize fields and preys preferentially on small fall armyworm larvae stunted by sublethal intoxication on Cry1Ab maize [ 68 ]. Furthermore, in four out of five locations fall armyworm larvae challenged on Cry1Ab maize foliage had reduced rate of population growth (see Fig 6 ), such that a reduced number of individuals may be passing resistance alleles to the next generation, thus slowing resistance evolution at least some field populations.…”

Section: Discussionmentioning

confidence: 99%

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Life-History Traits of Spodoptera frugiperda Populations Exposed to Low-Dose Bt Maize

et al. 2016

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Exposure to Bacillus thuringiensis (Bt) toxins in low- and moderate-dose transgenic crops may induce sublethal effects and increase the rate of Bt resistance evolution, potentially compromising control efficacy against target pests. We tested this hypothesis using the fall armyworm Spodoptera frugiperda, a major polyphagous lepidopteran pest relatively tolerant to Bt notorious for evolving field-relevant resistance to single-gene Bt maize. Late-instar larvae were collected from Bt Cry1Ab and non-Bt maize fields in five locations in Brazil, and their offspring was compared for survival, development, and population growth in rearing environment without and with Cry1Ab throughout larval development. Larval survival on Cry1Ab maize leaves varied from 20 to 80% among the populations. Larvae reared on Cry1Ab maize had seven-day delay in development time in relation to control larvae, and such delay was shorter in offspring of armyworms from Cry1Ab maize. Population growth rates were 50–70% lower for insects continuously exposed to Cry1Ab maize relative to controls, showing the population-level effect of Cry1Ab, which varied among the populations and prior exposure to Cry1Ab maize in the field. In three out of five populations, armyworms derived from Bt maize reared on Cry1Ab maize showed higher larval weight, faster larval development and better reproductive performance than the armyworms derived from non-Bt maize, and one of these populations showed better performance on both Cry1Ab and control diets, indicating no fitness cost of the resistance trait. Altogether, these results indicate that offspring of armyworms that developed on field-grown, single-gene Bt Cry1Ab maize had reduced performance on Cry1Ab maize foliage in two populations studied, but in other three populations, these offspring had better overall performance on the Bt maize foliage than that of the armyworms from non-Bt maize fields, possibly because of Cry1Ab resistance alleles in these populations. Implications of these findings for resistance management of S. frugiperda in Bt crops are discussed.

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Section: Discussionmentioning

confidence: 99%

“…Altogether, these findings and observations help explain why field performance of Cry1Ab-producing maize hybrids against S . frugiperda in Brazil have not reduced much since the beginning of their commercialization [ 56 , 57 , 67 , 69 , 70 ] despite evolution of field resistance in some populations [ 32 ]. In addition to S .…”

Section: Discussionmentioning

confidence: 99%

Life-History Traits of Spodoptera frugiperda Populations Exposed to Low-Dose Bt Maize

et al. 2016

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“…In the U.S., populations from overwintering areas in south Texas (TX) and south Florida (FL) migrate annually into various regions across the country [2] . S. frugiperda is a major target of both Bt maize and Bt cotton in North and South America [3] , [4] . In 2013 alone, approximately 50 MHa of Bt crops were planted in the Americas for insect pest management [5] , [6] .…”

Section: Introductionmentioning

confidence: 99%

Cry1F Resistance in Fall Armyworm Spodoptera frugiperda: Single Gene versus Pyramided Bt Maize

Huang

Qureshi

Meagher³

et al. 2014

PLoS ONE

266

288

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Evolution of insect resistance to transgenic crops containing Bacillus thuringiensis (Bt) genes is a serious threat to the sustainability of this technology. However, field resistance related to the reduced efficacy of Bt maize has not been documented in any lepidopteran pest in the mainland U.S. after 18 years of intensive Bt maize planting. Here we report compelling evidence of field resistance in the fall armyworm, Spodoptera frugiperda (J.E. Smith), to Cry1F maize (TC 3507) in the southeastern region of the U.S. An F2 screen showed a surprisingly high (0.293) Cry1F resistance allele frequency in a population collected in 2011 from non-Bt maize in south Florida. Field populations from non-Bt maize in 2012–2013 exhibited 18.8-fold to >85.4-fold resistance to purified Cry1F protein and those collected from unexpectedly damaged Bt maize plants at several locations in Florida and North Carolina had >85.4-fold resistance. In addition, reduced efficacy and control failure of Cry1F maize against natural populations of S. frugiperda were documented in field trials using Cry1F-based and pyramided Bt maize products in south Florida. The Cry1F-resistant S. frugiperda also showed a low level of cross-resistance to Cry1A.105 and related maize products, but not to Cry2Ab2 or Vip3A. The occurrence of Cry1F resistance in the U.S. mainland populations of S. frugiperda likely represents migration of insects from Puerto Rico, indicating the great challenges faced in achieving effective resistance management for long-distance migratory pests like S. frugiperda.

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“…The higher, although mild, damage of non-Bt corn by caterpillars observed in the second corn season may be due to the higher incidence of fall armyworm on the ears of non-Bt corn at this opportunity. This species is a notorious defoliator of corn plants in the Americas [ 42 , 43 ]. However, while the initial generations of S .…”

Section: Discussionmentioning

confidence: 99%

Spatial distribution and losses by grain destroying insects in transgenic corn expressing the toxin Cry1Ab

et al. 2018

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Insect pests are one of the factors that most impact plant yield. The magnitude of the losses and the spatiotemporal pest distribution in crops is a result of their interactions with the environment. Therefore, the understanding of the causes of production losses and the pest spatial patterns is important for the development of suitable sampling plans and pest management programs. Thus, this study aimed to quantify grain losses caused by insects and to determine the spatial distribution pattern of arthropod pest species in Bt and non-Bt corn. The prevailing insect pests in the corn ears were the earworm and fall armyworm caterpillars (Helicoverpa spp. and Spodoptera frugiperda), the cornsilk fly (Euxesta spp.), the maize weevil (Sitophilus zeamais), and the square-necked grain beetle (Cathartus quadricollis). The non-Bt corn was more attacked by the caterpillars and the weevil, while Bt corn was more affected by the cornsilk fly Euxesta spp. Spatial dependence was significant for the damage caused by the caterpillars, the grain beetle and the maize weevil in both the Bt and non-Bt corn genotypes. The range of the damage caused by the insects was between 9.0–9.7 m for the caterpillars, 6.9–12.20 m for the cornsilk fly, 10.7–80.4 m for the square-necked grain beetle, and 51.9–170.7 m for the maize weevil. The pattern of the spatial distribution of pest damage in both corn genotypes (i.e., Bt and non-Bt corn) was similar with a prevalence of moderate to strong spatial dependence and aggregate damage distribution. The plants near to the sampling points exhibited injury and infestation levels similar to those of the sampled plants.

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Genetically modified corn on fall armyworm and earwig populations under field conditions

Abstract: The effects of corn MON810 on the Spodoptera frugiperda (J.E. Smith)

Cited by 14 publications

References 16 publications

Life-History Traits of Spodoptera frugiperda Populations Exposed to Low-Dose Bt Maize

Life-History Traits of Spodoptera frugiperda Populations Exposed to Low-Dose Bt Maize

Cry1F Resistance in Fall Armyworm Spodoptera frugiperda: Single Gene versus Pyramided Bt Maize

Spatial distribution and losses by grain destroying insects in transgenic corn expressing the toxin Cry1Ab

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