8. SIGMEA has produced the first large-scale empirically based estimation of the economic impact of a GM crop for EU farmers.

Currently the only GM crop authorised for commercial cultivation in the EU is Bt maize, resistant to certain stem borer pests.   Spain has the largest surface of Bt maize in the EU and over 9 years of commercial experience in cultivation. The Spanish case presented an opportunity to study ex-post the agronomic and economic performance of a GM crop in the EU. Analyses of GM crop impacts on farm economics are usually based on surveys of farmers cultivating GM crops under commercial conditions. A face-to-face survey was conducted among Spanish commercial maize farmers with the aim both of obtaining data on the agronomic and economic performance of Bt maize during three growing seasons (2002–2004) and of comparing the socioeconomic profile of farmers who adopted Bt maize versus those who did not. The survey was conducted in the three leading Bt maize-growing regions (Aragon, Catalonia and Castilla-La Mancha), which accounted for ~90% of the Bt corn–growing area in Spain in 2006. A province was selected within each region based on the importance of maize cultivation and the presence of farmers growing Bt maize (the provinces of Zaragoza in Aragon, Albacete in Castilla-La Mancha and Lleida in Catalonia).

Survey results found that Bt maize, like other pest-control technologies, produced variable impacts on maize yields in different provinces, ranging from neutral to 11.8% yield increase. The regional variability depends mainly on local variations of pest pressure and damage. Yield gains for growers of Bt maize were translated into revenue increase since no differences were found in the price paid to farmers for Bt or conventional maize. Regarding production costs, Bt maize growers paid more for the seeds than conventional growers, but had reduced insecticide use and costs. On average, growers of conventional maize applied 0.86 insecticide treatments/year to control borers and other insects, versus 0.32 treatments/year applied by Bt maize growers. All things considered, the impact of Bt maize adoption on gross margin obtained by farmers in different provinces ranged from neutral to € 122/ha per annum. In the survey, the reason most quoted by farmers for adopting Bt maize was "lowering the risk of maize borer damage" followed by "obtaining higher yields".

Finally, the survey compared the socio-economic profiles of farmers adopting or not Bt maize varieties. No differences were found for the two groups of farmers for variables such as land ownership, farm size, experience as maize grower, education or training. The conclusion is that the differences in yields and gross margin should therefore be attributable to the adoption of Bt maize varieties.

SIGMEA has also produced the largest survey to estimate ex ante the potential adoption by farmers of three GM crops not yet authorized in the EU but widely grown elsewhere: Herbicide Tolerant (HT) oilseed rape, HT maize and Bt/HT maize (combining herbicide tolerance and insect resistance). It has also looked at the impact of proposed coexistence measures on the willingness of farmers to adopt GM crops. A face-to-face survey of 1214 European farmers with a questionnaire specifically designed for this study was the main source of data. Germany, France, Spain, Hungary, United Kingdom and Czech Republic were chosen as countries to be studied. All these countries are major producers of maize and/or oilseed rape.

Analyses of farmers' responses show that there is high potential adoption of HT oilseed rape and HT maize, as well as Bt/HT maize. On average, forty-one percent of the farmers surveyed in the six countries are prepared to plant these GM crops. This figure nevertheless depends to a large extent on the coexistence measures put in place by EU member states.