I would encourage a critical read of the paper that you reference, as the conclusions are not based on any careful analysis of the similarities and differences between North American and European production systems. As I indicated in a response to an earlier question about the Heinemann paper, I believe the authors’ “conclusions” are better characterized as assertions. First of all, it is important to recognize the multitude of factors that influence yields and pesticide use, such as climate, soils, farming practices, government subsidies and subspecies of the crop grown (which is different in Canada and Europe for oilseed rape). A more detailed analysis would explore the influence of all of these factors before attributing observed differences to any single factor, such as the adoption of GM crops. Instead, the Heinemann study compares overall trends in yields and pesticide use and uses these differences to draw conclusions about the impact of GM crops.
For pesticide use in particular, the analysis is extremely weak. The data that are used in the analysis are from FAO, which reports annual estimates of total pesticide use by country for all crops. Because the FAO data only present an aggregated estimate of pesticide use for all crops produced in a country, it would be extremely difficult to draw any conclusions based on these data alone. Further, despite the assertion by the authors that pesticide use reductions were observed in Switzerland and Germany (with no data shown in the paper), current FAO data show overall pesticide use increasing in both countries between 1995 and 2010. Perhaps most importantly though, simply comparing trends in the aggregate amount of pesticides used is problematic, as pesticides are applied at vastly different rates and are inherently different in their potential environmental and human health impacts.
The other important point that the Heinemann paper ignores is about the current and potential impact of GM crops in developing countries, where observed yield increases for adopters of GM crops are much greater than in developed countries, and pipeline technologies offer solutions to some critical production and nutritional constraints.