Brazilian farmers worried about ineffectiveness of GM corn variety

Brazilian farmers who grow genetically-modified corn are very worried with the apparent ineffectiveness of Bt-corn against pests, foremost caterpillars, which are claimed to be eliminated by the technology. Last year, Brazil experienced attacks of species that had never been registered before in the country. One of the highlights is the Helicoverpa Armigera (known as the earworm), which already accounted losses of millions of Brazilian Reals.

Bt-corn is obtained throughout genetic transformation of corn plants with Bacillus thuringiensis bacterium genes, stemming a plant production of toxic proteins for some insect species. The technology, created in the United States, was very frequently used - until then - due to its effectiveness. In the South American country, Bt seeds are used for approximately five years, being accounted for 80% of the total corn seeds sold in the market.

The issue has taken such dimension that it was discussed by the National Commission of Cereals, Oilseeds, and Fibers of Brazil's National Confederation of Agriculture and Livestock with the participation of farmers in the most affected states. "Bt-corn did not bring us the expected results. The losses cannot be quantified yet, but we expected a corn more resistant to insect pests", affirmed Rui Prado, president of the collegiate and of the Mato Grosso Federation of Agriculture and Livestock.

Prado revealed that the Commission intends to hear more farmers, so it can study measures to minimize the damages, such as the regulation of the use of the Bt variety. One of the alternatives is to institute a mandatory implementation of a "refuge area" - which is in other words the use of parts of the crops to plant conventional hybrid corn, and thus to attract the resistant insects and to reduce the incidence and proliferation of pests over the crops.

This solution was pointed by the chief of Center of Research from the Agricultural Research Company of the state of Minas Gerais (Epamig), José Mauro Valente Paes. "This ineffectiveness has occurred in Minais Gerais and other producing regions in the country. One of the main factors that fostered the resistance of insect pests towards Bt technology is the lack of a refuge area", argued the specialist. 

"In this space, which must measure between 10% and 15% of the total planted area and planted with conventional seeds, is where the natural enemies of the culture should pro-create, develop, and be naturally combated by the concurrent species. The lack of use of a refuge area by the producers fosters a resistant animals selection, which causes a loss of seed technology", explains Paes.

Other factor that compromises the technology is the difference among fabricators on the use of Bt proteins. "Companies invest constantly on seeds improvements, but is important that the farmer follows the guidance of manufacturers and seeks to be informed of which pests affects the crops, which Bt technology would best attend and which should be the size of the refuge area. Such care avoid technology loss and investments made by the farmer", adds the researcher.