Rootworms are now eating Bt corn which was genetically modified in order to be rootworm-resistant. The resistant bugs are not yet widespread, but if the bugs become more numerous and widespread, farmers may be forced to resume the use of pesticides.
As farmers continue to use the GM cop, this will hasten the development of the GM -resistant bugs.
Last month, rootworms collected from Iowa fields were able to pass resistance to the corn crop's toxins onto the next generation. The development of the resistance in these fields has been attributed to planting GM crops three consecutive years in a row.
Farmers are supposed to plant one fifth of their fields with un-modified corn where non-resistant rootworms would take refuge and then would dilute the GM-resistant gene pool, however may farmers do not practice this crop diversification.
Monsanto assures everyone that this might be an isolated incidence and it is unclear of how widespread the GM resistant rootworm might become . . . but it is estimated that about one third of the corn grown in the U.S. has Monsanto's "Cry3Bb1 gene" which is the main gene which carries the toxicity for rootworms in GM corn. If one third of our nation's corn crops contain the gene, it seems that the potential for widespread resistance is significant. This finding also could signal the development of superbugs which are resistant to other forms of GM crops.
Scientists are working on a new genetic modification to overcome superbugs called "RNA interference" which, Sarah Laskow explains in her Grist article "Monsanto fail: GMO crops are losing their pest control powers," builds genetic code into plants that "turns off essential genes of any bugs that eat it." As Laskow writes "At least, we hope it only applies to bugs."
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Wall Street Journal: http://online.wsj.com/article/SB10001424053111904009304576532742267732046.html