Safety research project: Environmental effects of Bt gene

(2000 – 2004) Bavarian State Research Center for Agriculture, Freising

The cultivation of Bt maize has been shown to have no negative effects on beneficial insects (earthworms, springtails, aphids, cicadas, parasitic wasps, lacewings, hover fly larvae, ladybirds, predatory bugs and spiders). It was noticed that there were shifts in occurrence of some groups in Bt maize fields. However, these shifts did not always occur consistently during the trial period. Application of an insecticide had a clear negative effect on various species.
Butterflies: In the laboratory, maize pollen from Bt176 varieties was found to have an adverse effect on caterpillars, but this has not been replicated in field trials, where no adverse effects have yet been found.

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Effects of Bt maize cultivation on various arthropods found in maize fields

(2001 – 2004) RWTH Aachen University, Institute of Environmental Research (Biology V) Chair of Ecology, Ecotoxicology, Ecochemistry

Analyses give no indication that Bt maize has any effect on the frequency and species diversity of non-target organisms. However, the sprayed insecticide was found to have a clear effect on some insect groups.
Butterflies in associate farmland flora: No differences were found between the Bt variant and the isogenic control in any of the three trial years. However, significantly fewer caterpillars were recorded on their fodder plants in the plots which had been treated with insecticide.

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Effect of Bt pollen on butterflies

(2001 – 2003)

Diamond-black, cabbage white and young peacock caterpillars presented higher mortality rates, ate less and grew more slowly in feeding experiments with Bt pollen (Bt176) compared with untreated control insects, showing varying levels of sensitivity. Older caterpillars are less sensitive than younger ones.
By contrast, cutworms (caterpillars that pupate in the soil) were scarcely affected by ingesting Bt pollen.
Mon810 pollen has a very low Bt toxin content. With Mon810-pollen no damage was found on the most sensitive species, the diamond-back moth, even with 80 pollen grains per caterpillar.

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Effects of Bt maize on butterflies and their antagonists

(2001 – 2004) Max Planck Institute (MPI) for Chemical Ecology, Department of Biochemistry, Jena

When damaged by caterpillar grazing, maize plants emit volatile substances (scents) which attract the caterpillars’ antagonists (parasitoids). In this way the plant defends itself indirectly against the insects that feed on it. This interaction between plant, caterpillar and parasitoid could be affected by altered scent emissions in Bt maize.
There were no qualitative differences in field and laboratory tests between the scents emitted by the different pairs of maize varieties (transgenic/non-transgenic). Normal varietal differences are far greater than the difference between Bt maize and its parent variety.

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Ecological impacts of insect-resistant Bt maize on various insects and the European corn borer

(1999 – 2002) RWTH Aachen University, Chair of Biology V, Aachen; Federal Biological Research Centre for Agriculture and Forestry (BBA)(since 2008 Julius Kühn Institute (JKI)), Institute for Biological Control, Darmstadt

The choice of maize type – Bt maize or a conventional isogenic reference variety – had no recognisable effect on the incidence of arthropods, aphids and their antagonists.
Caterpillars: Pollen from the transgenic maize line Bt176 had a negative effect on the caterpillars of the diamond-back moth and cabbage white butterfly. A species of surface caterpillar (caterpillars that pupate in the soil) was not noticeably affected.
Developing resistance. None of the larvae collected in the Bt maize fields were resistant to the Bt toxin.

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