New discussion on the negative consequences of large-scale Bt maize cultivation

12.01.2012 - A recent article in the Journal of Integrated Pest Management by Hutchison et al (2011) discussed a Testbiotech report published in 2010 (commissioned by Greenpeace Germany): New plant pest caused by genetically engineered corn: The spread of the western bean cutworm causes massive damage in the US (Then, 2010a). Hutchison et al (2011) are criticising this report because they are of the opinion that genetically engineered maize should not be regarded as the sole factor that influenced the range expansion of the western bean cutworm.

In Testbiotech’s opinion, the Hutchison et al (2011) article, written in conjunction with experts from Pioneer Hi-Bred and Dow AgroSciences (who are at the same time editors-in-chief of the Journal of Integrated Pest Management), brings up some interesting issues such as possible factors that might contribute to the spread of the western bean cutworm. The authors also give an overview of historical data on the prevalence of the western bean cutworm. They do not, however, present any new evidence to show that large-scale cultivation of Bt maize does not promote the spread of the western bean cutworm (Bt maize producing Cry1Ab). Therefore the explanation that the cultivation of genetically engineered maize promotes the spread of the western bean cutworm by reducing the abundance of its competitor species is still highly probable.

In this context, one should not overlook several other examples showing that the cultivation of Bt plants can indeed cause a shift in pest insect populations, but Hutchinson et al (2011) took none of these into consideration. Some of these examples are summarised in a further Testbiotech publication on the western bean cutworm published in a peer reviewed conference reader in 2010 (Then, 2010b).

While Testbiotech is ready to discuss some details as presented in the report, we note that the findings in the Hutchison et al (2011) article do not challenge the overall conclusion that Bt maize (producing Cry1Ab) is very likely to support the spread of the western bean cutworm. Other factors may also be involved, but their relative contribution needs to be evaluated. There is no doubt that several peer-reviewed studies have associated secondary pests with cultivation of genetically engineered crops.

During the preparation of the original report, the author, Christoph Then, contacted William Hutchison and invited him to give his comments. Hutchison refused to do so. It is somehow unusual that Hutchison not only comes up with his analysis such a long time after the publication of the original report, but that he gave no notification to its author. In conclusion, it appears that this publication is not meant to promote scientific debate but to conceal the possible negative consequences of large-scale Bt maize.

Testbiotech welcomes the discussion on this issue, since the spread of the western bean cutworm is an issue largely unknown to the wider public. If any new evidence on the underlying causes arises, Testbiotech will be more than happy to report on it.

References:

Hutchison, W.D., Hunt T.E., Hein G.L, Steffey K.L., Pilcher C.D., Rice, M. E., 2011, Genetically Engineered Bt Corn and Range Expansion of the Western Bean Cutworm (Lepidoptera: Noctuidae) in the United States: A Response to Greenpeace Germany, Journal of Integrated Pest Management, J. Integ. Pest Mngmt. 2(3): 2011;DOI:http://dx.doi.org/10.1603/IPM11016

Then, C., 2010a, New plant pest caused by genetically engineered corn. The spread of the western bean cutworm causes massive damage in the US, a Testbiotech Report, http://www.testbiotech.de/sites/default/files/WBC%20en_25_3_2010.pdf

Then, C., 2010b, New pest in crop caused by large scale cultivation of Bt corn, in: Breckling, B. & Verhoeven, R. (2010) Implications of GM-Crop Cultivation at Large Spatial Scales, Theorie in der Ökologie, Frankfurt, Peter Lang,
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