Short-term assessment of bt maize on non-target arthropods in Brazil

Odair Aparecido Fernandes,Samuel Martinelli,Marcos Faria,Vinícius Ferreira Carvalho,Gloverson Moro,Francisco Schmidt

doi:10.1590/s0103-90162007000300006

Abstract

Although not yet available for cultivation in Brazil, the effect of Bt maize hybrids on natural enemies and soil dwelling arthropods should be assessed prior to its release to growers. Trials were carried out during one growing season in two different locations with the genetically modified maize hybrids 7590-Bt11 and Avant-ICP4, comparing with their respective non-Bt isogenic hybrids. Arthropods were evaluated through direct observation on plants and pitfall traps. In general, no differences were observed between populations of earwig (Dermaptera: Forficulidae), lady beetles (Coleptera: Coccinellidae), minute pirate bug (Coleoptera: Anthocoridae), ground beetles (Carabidae), tiger beetles (Cicindelidae), and spiders (Araneae). There was no difference in egg parasitism of Helicoverpa zea (Boddie) by Trichogramma sp. (Hymenoptera: Trichogrammatidae). Thus, Bt maize hybrids expressing insecticide proteins Cry1A(b) and VIP 3A do not cause reduction of the main maize dweeling predators and parasitoids.

Highlights

Modified (GM) plants resistant to insects through the expression of Bacillus thuringiensis Berliner bacterial toxins (Bt) are considered a new pest management alternative for farmers
The objective of this study was to evaluate the effects of two genetically modified hybrids expressing B. thuringiensis insecticide proteins and their isogenic non-transgenic hybrids on herbivore natural enemies that occur in the Brazilian maize agroecosystem
No differences were observed between the Bt hybrids and their respective isogenic non-Bt genotypes regarding the average number of earwig, Doru luteipes (Scudder), adults per ten plants throughout the crop cycle (Figure 1)

Summary

Introduction

Modified (GM) plants resistant to insects through the expression of Bacillus thuringiensis Berliner bacterial toxins (Bt) are considered a new pest management alternative for farmers. This technology has made possible the efficient and specific control of certain lepidopterous pests (Buntin et al, 2001; Stewart et al, 2001; Wu et al, 2003; Kumar & Kumar, 2004). Romeis et al (2004) showed that the Cry1A(b) toxin had no direct effect on C. carnea These authors argued that earlier reported negative effects of Bt maize on these predators were due to prey quality mediated effects rather than to the direct effects of the toxin

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Conclusion