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Officials See Growing Rootworm Populations in Genetically Engineered Corn

April 5, 2010

University researchers, such as Ken Ostlie, a University of Minnesota Extension entomologist, are beginning to document what many in agriculture fear most: pest resistance. And this isn’t just any pest resistance, or any crop or any pest management system, for that matter. During the 2009 growing season, researchers have found widespread growth in rootworm populations in corn fields planted with genetically modified corn. This has recently been reported in a Progressive Farmer article: http://www.dtnprogressivefarmer.com/dtnag/common/link.do?symbolicName=/free/crops/news/template1&product=/ag/news/production/features&vendorReference=0702DAAC&paneContentId=70115&paneParentId=70104  In a documented case in southern Minnesota, rootworms destroyed the genetically engineered corn while the non-engineered corn planted in the same field suffered little to no affect. Studies and reports from across the Corn Belt indicate similar situations.

The National Corn Growers Association has argued this unforeseen problem is not a fatal error of genetically modified corn. This problem can more simply be placed upon the shoulders of farmers failing to plant enough refuge, or non-genetically modified corn planted for the purpose of drawing rootworms away from genetically modified corn. However, a number of studies, such as that conducted by Ostlie, were of fields with adequate refuge. The problem, it appears, runs much deeper than “operator error” and instead point to impacts stemming from long-term use of genetically modified crops. Genetically engineered crops are a relatively recent technological advancement of the 1980s and 1990s. The simple definition or explanation is that rather than using the hybridization process, a process created in the 1940s which uses natural methods of plant mating and reproduction to produce stronger seed varieties, genetic modification involves entering a seed’s gene code and chemically modifying genes to produce desired traits. Compared to genetic engineering, hybridization offered a much slower process with fewer opportunities for manipulation. The process involved patience, a lot of trial and error, and a bit of luck.

Unfortunately, while genetic modification has created the opportunity to speed up the plant improvement process, it has also led agriculture down an uncharted course fraught with uncertainty and unknown consequences. Having now traveled down that path for just under a quarter of a century some of the problems are now coming into view.

 Pest Resistance Grows

As more and more acres become dedicated to corn-corn rotation and are planted with genetically modified corn, the weaknesses of genetic modification are becoming increasingly apparent. Thus, two problems could explain the rootworm resistance. Continuous corn offers rootworm and other pests a continuous feed supply, allowing for populations to build. However, continuous corn has been used in the past before the implementation of genetic modification without such a rapid and widespread growth in pest resistance. A more likely explanation involves the method of pest deterrence in genetically modified corn. To create pest resistance in seeds, geneticists manipulate a protein in the genetic sequence. This manipulation mimics the protein sequence of low dose insecticides. And therein lays the problem. Pests most quickly develop resistance at low doses. Studies over short periods of time would not be able to measure the growth in pest resistance that becomes evident only after a few years of implementation. However, studies coming out of Missouri have shown a 12-fold increase in pest survival after just six generations of insects were exposed to one modified gene trait.

Additionally, studies have shown that volunteer corn shows a decreased level of the desired protein compared to newly established seeds. This decreasing pest resistance capacity indicates a potential pitfall not just for farmers using genetically modified seeds, but for all farmers. One concern with widespread use of genetically modified crops is the potential for contamination through natural plant breeding with non-modified crops when planted in neighboring fields. Through this natural hybridization process, this genetic modification, some argue now a proven genetic weakness, could enter the larger corn gene pool. In short, we’ll have let the genie out of the bottle.

Where to Go

As psychologists note, the first step to solving any problem is admitting there is a problem. It appears the agriculture sector may not quite be there yet, but awareness of this problem with genetically modified crops will only continue to grow. And yes, there will always be a few out there who absolutely refuse to admit a problem. Just look at the global warming deniers as an example. No level of scientific information will change there mind. For the rest of us willing to objectively observe scientific evidence, what is our next step? Well, we have three options. One would be to attempt to increase gene manipulation to stay ahead of pests. This would require taking ever large gambles with the genetic pool and the food agriculture is charged with providing. The second would be to stop use of genetically modified crops until we gain a better understanding of the consequences and establish protocols for preventing the contamination of the larger gene pool by potentially flawed modified genes. Finally, we could shift resources from genetic modification to studying and establishing pest management techniques that work with nature rather than attempting to break nature.

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