Effect of Maize Lines on Larval Fitness Costs of Cry1F Resistance in the European Corn Borer (Lepidoptera: Crambidae)

Background: Lepidopteran and coleopteran species are the most important pests in maize. They can be controlled using genetically modified (GM) crops expressing insecticidal Bacillus thuringiensis (Bt) proteins. The long-term success of this technology demands a pest resistance management. Important information for the successful management of resistance is the baseline susceptibility of the different target pests to the different Bt proteins. The data on baseline susceptibility should enable risk assessors and managers to assess whether a GM maize produces a Bt protein in a high-dose to specific target organisms and resistance has evolved during the commercial cultivation of this GM maize events.Methods: Our systematic search followed an a priori protocol including the database platforms Web of Science, Scopus, CAB abstracts, Science Direct and JSTOR. We additionally conducted a Google scholar search. We collated all search results and screened all retrieved articles using predetermined inclusion criteria. We identified 30 studies, which fulfilled the criteria of including a relevant Bt protein, a relevant species, an appropriate endpoint, and fieldderived pest generations reared in the laboratory no longer than three generations. We then made a quality assessment to discover if the studies considered the dose response curves with confidence intervals, described the protein source, tested the protein concentration and the protein activity via positive controls, use more than ten larvae per concentration, more than two replications, and more than five protein concentrations. Since no quantitative synthesis was possible the synthesis of the results was done in a narrative form.Results: Seventy percent of the studies fulfilled five or more criteria and 17% fulfilled four of the seven criteria. Six Bt proteins were tested on one or more of the four species Ostrinia nubilalis, Helicoverpa armigera, Sesamia nonagrioides, and Diabrotica virgifera virgifera. We extracted the baseline susceptibility for the given protein-species-combinations and the test method with the Bt protein applied either on the surface of the diet or incorporated. Although, the data displays a high heterogeneity and are thus hard to compare, they give an overview of the baseline susceptibility of lepidopteran/coleopteran pests to Bt proteins. Conclusion:Our systematic review illustrates the heterogeneity of the data and indicates the necessity of standard protocols for testing susceptibility of insect pests, which provide comparable data. The cultivation of Bt crops, as with any other plant protection measure, is likely to result in resistance evolution in the target pests. Industry, policy makers, and research should combine knowledge to protect the benefits of this technology.

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“…The aim of the different screened studies varied. Many toxicity studies tested for survival [17][18][19] or mortality only (e.g. [20][21][22]).…”

Section: Discussionmentioning

confidence: 99%

Baseline susceptibility of different European lepidopteran and coleopteran pests to Bt proteins expressed in Bt maize: a systematic review

Priesnitz¹,

Vaasen²,

Gathmann³

2016

Environ Evid

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“…Diet bioassays conducted following backcrossing and selection on Cry1F confirmed that the resistant strain was still highly resistant to Cry1F (Petzold‐Maxwell et al. ).…”

Section: Methodsmentioning

confidence: 99%

“…Maize plants were grown in a greenhouse in 9‐l pots (Classic 1000, Hummert International, Earth City, Missouri) as described in Petzold‐Maxwell et al. (). Greenhouse temperature throughout the experiment was 25.9°C ± 7.6°C (mean ± SD) for experiment one and 22.3°C ± 6.1°C for experiment two.…”

Section: Methodsmentioning

confidence: 99%

“…By contrast, no fitness costs were found for larval survival, growth rate or mass when Cry1F‐resistant insects were tested on three different maize lines (Petzold‐Maxwell et al. ). It is important to note that with the exception of Petzold‐Maxwell et al.…”

Section: Introductionmentioning

confidence: 99%

“…It is important to note that with the exception of Petzold‐Maxwell et al. (), these studies were conducted with insects reared on artificial diets optimized for growth and development. In general, fitness costs of Bt resistance are observed more frequently when insects are fed plants compared to artificial diets (Gassmann et al.…”

Section: Introductionmentioning

confidence: 99%

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Fitness costs associated with Cry1F resistance in the European corn borer

Petzold-Maxwell

Siegfried

Hellmich

et al. 2016

J Applied Entomology

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Crops producing insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are widely planted to manage insect pests. Bt crops can provide an effective tool for pest management; however, the evolution of Bt resistance can diminish this benefit. The European corn borer, Ostrinia nubilalis Hübner, is a significant pest of maize and is widely managed with Bt maize in the Midwest of the United States. When Bt crops are grown in conjunction with non‐Bt refuges, fitness costs of Bt resistance can delay the evolution of resistance. Importantly, fitness costs often vary with ecological factors, including host‐plant genotype and diapause. In this study, we examined fitness costs associated with Cry1F resistance in O. nubilalis when insects were reared on three maize lines. Fitness costs were tested in two experiments. One experiment assessed the fitness costs when Cry1F‐resistant and Cry1F‐susceptible insects were reared on plants as larvae and experienced diapause. The second experiment tested resistant, susceptible and F1 heterozygotes that were reared on plants but did not experience diapause. Despite some evidence of greater adult longevity for Cry1F‐resistant insects, these insects produced fewer fertile eggs than Cry1F‐susceptible insects, and this occurred independent of diapause. Reduced fecundity was not detected among heterozygous individuals, which indicated that this fitness cost was recessive. Additionally, maize lines did not affect the magnitude of this fitness cost. The lower fitness of Cry1F‐resistant O. nubilalis may contribute to the maintenance of Cry1F susceptibility in field populations more than a decade after Cry1F maize was commercialized.

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Role of Seed Quality in Improving Crop Yields

Wimalasekera

2015

Crop Production and Global Environmental Issues

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Effect of Maize Lines on Larval Fitness Costs of Cry1F Resistance in the European Corn Borer (Lepidoptera: Crambidae)

Cited by 13 publications

References 50 publications

Baseline susceptibility of different European lepidopteran and coleopteran pests to Bt proteins expressed in Bt maize: a systematic review

Baseline susceptibility of different European lepidopteran and coleopteran pests to Bt proteins expressed in Bt maize: a systematic review

Fitness costs associated with Cry1F resistance in the European corn borer

Role of Seed Quality in Improving Crop Yields

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