Considering the recurrent requests of the European Commission for reanalysis of the 2005 Scientific Opinion on genetically modified (GM) maize event 1507, the European Food Safety Authority (EFSA) asked the Panel on Genetically Modified Organisms (EFSA GMO Panel) to update the previous environmental risk assessment (ERA) of maize 1507 in light of the scientific data and methodology currently available, and to consider the possible adverse effects that the cultivation of maize 1507 might have on non-target organisms (e.g., Lepidoptera). In addition, the EFSA GMO Panel was asked to reconsider its recommendations to risk managers for methods to reduce exposure and mitigate risks linked to maize 1507 cultivation.
In delivering its Scientific Opinion, the EFSA GMO Panel considered the initial notification C/ES/01/01 for cultivation of maize 1507, including additional data supplied by the applicant and relevant scientific publications.
The EFSA GMO Panel recalibrated its mathematical model, developed by Perry et al. (2010) for the ERA of a similar insect resistant maize (event MON 810), in order to simulate and assess potential adverse effects resulting from the exposure of non-target Lepidoptera (butterflies and moths) to pollen from maize 1507 under representative EU cultivation conditions, and extended it to estimate the efficacy of certain mitigation measures. The 2005 EFSA GMO Panel Scientific Opinion on maize 1507 supported 'management recommendations for the cultivation of maize 1507 [with] measures to reduce exposure of non-target Lepidoptera (as well as the target pest), such as the use of non-transgenic border rows as refugia for the target that would also reduce exposure of field margin weeds (and hence non-target Lepidoptera) to pollen from Bt-maize’. In this Scientific Opinion, the EFSA GMO Panel has used new evidence to explore the complexities of this issue.
The EFSA GMO Panel concludes that the cultivation of maize 1507 could have the following adverse effects on the environment in the context of its intended uses (1) the adoption of altered pest control practices with higher environmental load due to potential evolution of resistance to the Cry1F protein in populations of exposed lepidopteran target pests, and (2) reductions in populations of certain highly sensitive non-target lepidopteran species where high proportions of their populations are exposed over successive years to high levels of maize 1507 pollen deposited on their host-plants. In situations where highly sensitive non-target Lepidoptera populations might be at risk, the EFSA GMO Panel recommends that mitigation measures are adopted to reduce exposure.
Considering the wide range and variability of agro-ecosystems and protection goals within the EU, this EFSA GMO Panel Scientific Opinion provides risk managers with tools to estimate global and, where needed local, mortality of exposed non-target Lepidoptera, both before and after different mitigation measures are put in place, and for different host-plant densities. This enables risk managers to choose mitigation measures proportionate to the level of identified risk and to the protection goals pertaining to their region. Special attention should be paid to the degree of large-scale exposure as mitigation measures are only needed when the proportion of maize and uptake of maize 1507 are sufficiently high, regardless of the other parameters. If maize 1507 cultivation remains below 5% of the Utilized Agricultural Area, the global mortality is predicted to remain below 1%, even for extremely highly sensitive species, and then risk management measures are not required. Whenever mitigation measures are needed, the implementation of non-Bt-maize border rows will reduce the mortality of non-target lepidopteran species for both within fields and in field margins.
For protected lepidopteran species in habitats according to Directive 2004/35/EC, it is recommended that maize 1507 is not cultivated within 30 m of their habitat boundary, so that exposure and hence the risks to larvae of lepidopteran populations are minimised in these areas.
In addition to the specific concern on non-target Lepidoptera, the EFSA GMO Panel considered the possible adverse effects of maize 1507 on other non-target organisms, in order to update, where appropriate, its previous evaluations in light of new relevant scientific literature. Having considered all available relevant scientific literature, the EFSA GMO Panel concludes that no new scientific information has been made available that would invalidate the conclusions of its previous Scientific Opinions on maize 1507.
The possible resistance evolution to the Cry1F protein in lepidopteran target pests is identified by the EFSA GMO Panel as a concern associated with the cultivation of maize 1507, as resistance evolution may lead to altered pest control practices that may cause adverse environmental effects.
The EFSA GMO Panel recommends case-specific monitoring (CSM) to assess the efficacy of risk management measures put in place to reduce levels of risk and scientific uncertainty for (1) the possible resistance evolution to the Cry1F protein in lepidopteran target pests, and (2) the risk to sensitive non-target Lepidoptera from maize 1507 pollen. The EFSA GMO Panel considers that risk managers should adapt monitoring methodologies to their local receiving environments and management systems.
For (1), the EFSA GMO Panel reiterates its earlier recommendation that appropriate insect resistance management (IRM) strategies relying on the 'high dose/refuge' strategy should be employed, in order to delay the potential evolution of resistance to the Cry1F protein in lepidopteran target pests. In the case of a cluster of fields with an aggregate area greater than 5 ha of Bt-maize, the EFSA GMO Panel advises that there shall be refugia equivalent to 20% of this aggregate area, irrespective of individual field and farm size. In addition, the EFSA GMO Panel makes additional recommendations to the applicant like (a) to focus the sampling of lepidopteran target pests in 'hotspot areas' over time; (b) to include in the samplings surviving lepidopteran target pests within maize 1507 fields in order to detect potentially resistant individuals; (c) to consider regionally important lepidopteran pests (other than corn borers) of maize 1507; and (d) to revise the monitoring protocol aiming at a detecting resistance allele frequency below 5% in 'hotspot areas'. The EFSA GMO Panel recommends caution when predicting future responses of the European and Mediterranean corn borer in the EU based on experiences elsewhere, as resistance evolution in target insect pests is dependent upon many factors. Therefore, the EFSA GMO Panel, while agreeing with the 'high dose/refuge' strategy, recommends the periodic re-evaluation of the adequacy and efficacy of this IRM strategy.
For (2), the EFSA GMO Panel recommends to carry out further field studies on non-target Lepidoptera. The purpose of these studies should be to estimate whether non-target Lepidoptera larvae, with a high sensitivity to the Cry1F protein, are in reality feeding on host-plants in and adjacent to maize fields at the time of pollen deposition, and if so (a) to estimate the proportions of these populations likely to be affected; and (b) to determine the overall effect on maintaining a favourable status of these populations.
The EFSA GMO Panel agrees with the general surveillance (GS) approach of the applicant (1) to establish farmer questionnaires as a reporting format of any on-farm observations of effects associated with the cultivation of maize 1507, (2) to use existing monitoring networks which observe changes in biota and production practices from farm up to regional level to obtain data on environmental impacts in the landscape where maize 1507 is cultivated, (3) to review all new scientific, technical and other information pertaining to maize 1507, and (4) to develop stewardship programs for the introduction, marketing, management and stewardship of maize 1507, but requests that its proposals to strengthen GS are implemented. The EFSA GMO Panel considers that the current plan for GS, and in particular the methodology, needs further details according to the requirements laid down in its 2011 Scientific Opinion providing guidance on post-market environmental monitoring (PMEM) of GM plants, as well as its Scientific Opinion on the annual 2009 PMEM report on maize MON 810. The EFSA GMO Panel agrees with the reporting intervals and modalities proposed by the applicant.
In areas where other lepidopteran pests than the European and Mediterranean corn borer are important targets of maize, they might also be subject to resistance evolution due to exposure to the Cry1F protein expressed in maize 1507. Therefore, the EFSA GMO Panel recommends these species are considered by the applicant in the context of the IRM strategy, CSM to monitor resistance evolution to the Cry1F protein in those species, as well as GS through farmer questionnaires.
The EFSA GMO Panel concludes that, subject to appropriate management measures, maize 1507 cultivation is unlikely to raise safety concerns for the environment.