Genetically Modified Organisms

Cultivation of genetically modified maize Bt11 is unlikely to harm environment and agriculture in Norway


Report no: 2017: 22

Published: 06.07.2017

Key message:

Based on current knowledge, it is unlikely that cultivation of insect-resistant and herbicide-tolerant genetically modified maize Bt11 will have negative effects on biodiversity or agriculture in Norway, concludes the Norwegian Scientific Committee for Food Safety, VKM.

The Norwegian Environment Agency and the Norwegian Food Safety Authority requested the Norwegian Scientific Committee for Food Safety for an opinion of potential risks to biodiversity and agriculture in Norway associated with import of seeds and cultivation of insect-resistant and herbicide-tolerant genetically modified maize Bt11.

VKM was also requested to assess the applicant´s post-market environmental monitoring plan, and the management measures suggested in the draft implementing decision of the European Commission.

Maize Bt11

The genetically modified maize Bt11has been developed to provide protection against certain lepidopteran target pests, such as the European corn borer (ECB, Ostrinia nubilalis), and some species belonging to the genus Sesamia.

Maize Bt11 also expresses the phosphinothricin-N-acetyltransferase (pat) gene, derived from the soil microorganism Streptomyces viridochromogenes strain Tu494, which encodes an enzyme: phosphinothricin acetyl transferase (PAT).

The encoded PAT protein confers tolerance to the herbicidal active substance glufosinate-ammonium. The PAT protein produced by maize Bt11 has been used as a selectable marker to facilitate the selection process of transformed plant cells and is not intended for weed

management purposes. Since the scope of the notification C/F/96.05.10 does not cover the use of glufosinate-ammonium-containing herbicides on maize Bt11, potential effects due to the use of such herbicides on maize Bt11 are not considered by VKM.

Environmental risk

Maize is the only representative of the genus Zea in Europe, and there are no cross-compatible wild or weedy relatives outside cultivated maize with which maize can hybridise and form backcross progeny.

There are no reports of the target lepidopteran species attaining pest status on maize in Norway. Since there are no Bt-based insecticides approved for use in Norway, and lepidopteran pests have not been registered in maize, issues related to resistance evolution in target pests are not relevant at present for Norwegian agriculture.

Published scientific studies showed that the likelihood of negative effects of Cry1Ab protein on non-target arthropods that live on or in the vicinity of maize plants is low. The VKM also concludes that cultivation of maize Bt11 is not considered to represent a threat to the prevalence of red-listed species in Norway.

Exposure of nontarget organisms to Cry proteins in aquatic ecosystems is likely to be very low, and potential exposure of Bt toxins to non-target organisms in aquatic ecosystems in Norway is considered to be negligible.

VKM concludes that, although the data on the fate of the Cry1Ab protein and its potential interactions in soil are limited, the relevant scientific publications analysing the Cry1Ab protein, together with the relatively broad knowledge about the environmental fate of other Cry1 proteins, do not indicate significant direct effects on the soil environment.

Despite limited number of studies, most studies conclude that effects on soil microorganisms and microbial communities are transient and minor compared to effects caused by agronomic and environmental factors. However, data are only available from short-term experiments and predictions of potential long-term effects are difficult to deduce.


VKM concludes that separation distances of 200 meters most likely will ensure coexistence between genetically modified maize and conventional and organic maize varieties in Norway.


Maize Bt11 is approved for import, further processing and for use as food and feed in the EU. An application for approval of Bt11 for cultivation has been processed in EU since 1996. The European Food Safety Authority, EFSA, has considered the application a number of times from 2005 to 2016. In 2016, the Commission submitted a proposal to approve the application.

VKM delivered a health and environmental risk assessment of Bt11 maize for import, processing and use as food and feed in 2014. In this assignment, VKM is asked to assess the risk of adverse impacts on biodiversity and Norwegian agriculture when cultivating the genetically modified maize. The assessment is part of the Norwegian Environment Agency’s preparation for a possible approval in the EU.

The VKM Panel on Genetically Modified Organisms has conducted this opinion.

Other popular articles

The Norwegian Scientific Committee for Food and Environment

T: 21 62 28 00

P.O. Box 222 Skøyen
0213 Oslo

©2004-2023 VKM