Statement supplementing the evaluation of the environmental risk assessment and risk management recommendations on insect resistant genetically modified maize Bt11 for cultivation

GMO, maize (Zea mays), Bt11, Cry1Ab, insect resistance, non-target organisms, Lepidoptera, environmental safety, post-market environmental monitoring, mathematical modelling
First published in the EFSA Journal
8 December 2011
30 November 2011
Last Updated
24 February 2012. This version replaces the previous one/s.


In this Statement, the EFSA GMO Panel supplements its previous evaluations of the potential impact of maize Bt11 cultivation on a range of non-target lepidopteran species using existing data on species sensitivity and considering various scenarios of exposure which may occur across Europe. The mathematical model, initially developed for maize MON 810 and recently recalibrated for maize 1507, was used to estimate the efficacy of risk mitigation measures. In situations where „extremely sensitive‟ non-target Lepidoptera populations might be at risk, the EFSA GMO Panel recommends that risk mitigation measures are adopted to reduce exposure. Risk managers are provided with tools to estimate global and, where needed local, mortality of exposed non-target Lepidoptera, both before and after different risk mitigation measures are put in place, and for different host-plant densities. Risk mitigation measures are only needed when the proportion of maize and uptake of maize Bt11 (and/or maize MON 810) are sufficiently high, regardless of the other parameters. If maize Bt11 (and/or maize MON 810) cultivation remains below 7.5% of the regional Utilized Agricultural Area, then risk mitigation measures are not required. In addition, the EFSA GMO Panel recommends that appropriate insect resistance management (IRM) strategies for maize Bt11, which should be integrated with those of other Cry1Ab-expressing maize events currently grown commercially in the EU, are implemented in order to delay the possible resistance evolution to the Cry1Ab protein in target pests. The EFSA GMO Panel also considers that post-market environmental monitoring and IRM need to be revised. The EFSA GMO Panel concludes that, subject to appropriate management measures, maize Bt11 cultivation is unlikely to raise additional safety concerns for the environment compared to conventional maize. The EFSA GMO Panel considers that the conclusions on the risk to non-target Lepidoptera from maize Bt11 apply equally to maize MON 810.

Panel members at the time of adoption

Hans Christer Andersson, Salvatore Arpaia, Detlef Bartsch, Josep Casacuberta, Howard Davies, Patrick du Jardin, Gerhard Flachowsky, Lieve Herman, Huw Jones, Sirpa Kärenlampi, Jozsef Kiss, Gijs Kleter, Harry Kuiper, Antoine Messéan, Kaare Magne Nielsen, Joe Perry, Annette Pöting, Jeremy Sweet, Christoph Tebbe, Atte Johannes von Wright, and Jean-Michel Wal
Panel on Genetically Modified Organisms
gmo [at]
EFSA Journal 2011;9(12):2478
Question Number
On request from
European Commission