Fifteen years ago genetically engineered crops hit the market much to the delight of farmers. These new Roundup-tolerant crops allowed farmers to simply spray the herbicide Roundup over their fields and everything died – except the corn, cotton, and soybeans.
Recently, farmers have realized that certain weeds weren’t dying anymore; in Georgia that plant is Palmer Amaranth, commonly called pigweed. This strain of pigweed has a genetic mutation that makes it resistant to Glyphosate, the weed killing chemical in Roundup. Thirteen states are reporting weed resistance and farmers’ associations are reporting 103 biotypes of weeds with herbicide resistance.
Glyphosate is the most used herbicide in the United States and while the chemical has been associated with deformities in a host of laboratory animals, its impact on humans remains unclear; the Environmental Protection Agency (EPA) considers glyphosate to be relatively low in toxicity, but does post the greatest danger to amphibians. Fish and aquatic invertebrates are more sensitive to Roundup, which is not registered for aquatic uses.
Farmers are now looking for alternate solutions to manage the weeds and they are turning toward Stanley Culpepper; a weed scientist at the University of Georgia and is the state’s expert on cotton weeds, for help. He says the days of easy weed killing are over and that farmers are going to have to spray a lot of different chemicals to overcome the weeds and some will kill their crops if care isn’t taken. Culpepper believes that the key to surviving the herbicide resistant weeds it to try lots of different things; some involve chemicals and some doesn’t, but it will mean more work.
However, another extremely tempting solution for farmers will be a new batch of engineered crops that will be resistant to the herbicide needed to kill the pigweed. Dow AgroSciences, Monsanto, and Bayer CropScience, three big cotton seed companies; plan to sell such a seed within the next few years. Farmers will be able to spray 2,4-D (one of two ingredients used in the production of Agent Orange) and dicamba right over their crops like they are doing now with Roundup. Dow Agrosciences has already asked the US Department of Agriculture to approve genetically modified corn, which will allow farmers to spray with 2,4-D.
David Mortensen, a weed ecologist at Penn State University and other environmentalists are angry about these new products. Mortensen predicts that weeds will evolve and develop resistance to these new herbicides leading to an endless cycle of new crops and new chemicals. “When one herbicide fails, you add a second herbicide, and then a third herbicide to the package. And I am convinced that this is not a sustainable path forward.”