Bt maize in Europe: higher yields, lower use of insecticides

The first large-scale empirical study on agronomic and economic performance of Bt maize in Spain suggests that it leads to better results, higher returns and lower costs than does conventional maize. However, future socioeconomic analyses of GM crops need additionally to consider the costs incurred to ensure coexistence with non-GM crops during the adoption of GM crops by farmers.

In June, the Institute for Prospective Technological Studies of the Joint Research Centre (JRC) released the results of a face-to-face survey with 402 Spanish maize farmers, including adopters and non-adopters of Bt maize. For the first time, data on the agronomic and economic impact of adoption of Bt maize during three growing seasons are available. The survey was conducted in the three leading Spanish GM corn-growing regions of Aragón, Catalonia and Castilla-La Mancha. Spain is the largest producer of maize in the EU and has grown GM corn since 1997. The three regions surveyed account for 90 per cent of Spanish Bt maize production. The farmers involved in the study produce maize for the manufacture of feed.

The survey shows that growers of Bt maize experienced higher average yields than do growers of conventional maize and, as a consequence, higher economic returns. Particularly, growers of Bt maize in Aragón were able to increase their crop production by nearly 12 per cent. In comparison to growers of conventional maize, Bt farmers had to pay more for seeds but were able to cut overall costs because the corresponding usage of insecticides was considerably lower (0,32 insecticide treatments per year compared to 0,86 treatments). Since farmers were paid similar prices for Bt and conventional maize, the annual impact of the adoption of Bt maize on gross margin ranged from neutrality to €122 per hectare. The authors of the study emphasised that differences in yields and gross margin are attributable to the adoption of Bt maize and not to differences in the socio-economic profiles or technical capability of the farmers surveyed.

Growers of Bt maize expressed the highest degree of satisfaction with regard to the fact the adoption of such varieties considerably reduces the risk of maize borer damage. In the past, such damage had caused enormous yield losses in conventional maize. As a consequence, Bt maize today accounts for nearly 60 per cent of maize acreage in regions that traditionally have displayed high infestation with the corn borer. The resulting perception of increased economic security played a much greater role for farmers than did the prospect of higher yields or better yield quality.

Results of the study may provide a basis for future cost calculations, including the costs caused by ensuring co-existence with non-GM crops. Most EU Member States currently are drafting or adopting individual coexistence measures for the cultivation of GM crops. Therefore, the gross margin of GM maize production may differ significantly between individual EU countries.