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

PLoS One. 2018 Aug 10;13(8):e0201201. doi: 10.1371/journal.pone.0201201. eCollection 2018.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacillus thuringiensis Toxins
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / toxicity*
  • Brazil
  • Coleoptera / pathogenicity
  • Diptera / pathogenicity
  • Edible Grain / genetics
  • Edible Grain / parasitology
  • Endotoxins / genetics*
  • Endotoxins / toxicity*
  • Genotype
  • Hemolysin Proteins / genetics*
  • Hemolysin Proteins / toxicity*
  • Herbivory
  • Insecta / pathogenicity*
  • Moths / pathogenicity
  • Pest Control, Biological / methods
  • Plants, Genetically Modified
  • Spodoptera / pathogenicity
  • Weevils / pathogenicity
  • Zea mays / genetics*
  • Zea mays / growth & development
  • Zea mays / parasitology*

Substances

  • Bacillus thuringiensis Toxins
  • Bacterial Proteins
  • Endotoxins
  • Hemolysin Proteins
  • insecticidal crystal protein, Bacillus Thuringiensis

Grants and funding

This work was supported by Fundação de Amparo à Pesquisa do Estado de Minas Gerais and Conselho Nacional de Desenvolvimento Científico e Tecnológico who provided resources and the Post-Graduate Program in Entomology and Plant Science at the Federal University of Viçosa. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.