Supporters of genetically modified organisms (GMOs) say that they lower the use of pesticides and benefit the environment. However, the record demonstrates that there are growing negative environmental impacts from GMOs. One major problem caused by the widespread use of GMOs, and the herbicides and pesticides they were developed to withstand, is the emergence of superweeds and superbugs - plants and insects now resistant to these chemicals.
Contrary to the claim made by the biotech companies producing and patenting the genetically modified seeds, herbicide and pesticide use has actually increased since the adoption of GMO crops. A study published by Environmental Sciences Europe found that between the years 1996 and 2011, herbicide use in the United States increased by 527 million pounds. Pesticide use is estimated to have increased by 404 million pounds, about 7%.
This increased use of herbicides and pesticides in our agriculture has accelerated the evolution of weeds and insects to withstand these chemicals.
The most prevalent herbicide is Monsanto’s Roundup (glyphosate). According to a report by Food & Water Watch, the total amount of Roundup applied on crops of soybeans, corn, and cotton (three major genetically engineered crops) increased tenfold from 1996 to 2012. Therefore, it’s no surprise that Roundup-resistant weeds were the first to appear. In a survey of US farmers, nearly half (49 percent) said they had Roundup-resistant (glyphosate-resistant) weeds on their farm in 2012, up from 34 percent of farmers in 2011.
graph by Food & Water Watch
The USDA also recognizes the increase in herbicide use.The USDA’s recent report, Genetically Engineered Crops in the United States, states “HT [herbicide tolerant] adoption likely reduced herbicide use initially, but herbicide resistance among weed populations may have induced farmers to raise application rates in recent years, thus offsetting some of the economic and environmental advantages of HT corn adoption regarding herbicide use.”
Weed resistance to Roundup has forced farmers to turn to higher-risk herbicides such as 2,4-D, one of the components of Agent Orange used in the Vietnam War. As a supposed solution to the Roundup-resistance, biotech companies have genetically engineered corn and soybeans to be tolerant of 2,4-D. As the biotech companies try to get these new crops approved, scientists and organizations worry what effect that will have on the environmental, air, and water. The study from Environmental Sciences Europe projects that if these new crops are approved, the volume of 2,4-D sprayed could increase herbicide usage by about another 50%.
Unfortunately, 2,4-D is following in Roundup’s footsteps as plants develop resistance to 2,4-D as well. The scientific journal Weed Science reported that waterhemp, a major problem in the Midwest, was discovered to be resistant to 2,4-D in Nebraska. This adds to the 17 weeds already known to be resistant to 2,4-D.
Even the USDA’s report mentions the problem with adopting crops tolerant of 2,4-D. “Thus, weed resistance may be offsetting some of the economic and environmental advantages of [herbicide tolerant] HT crop adoption regarding herbicide use. Moreover, herbicide toxicity may soon be negatively affected (compared to glyphosate) by the introduction (estimated for 2014) of crops tolerant to the herbicides dicamba and 2,4-D.”
Rootworm, one of the most destructive pests in corn production, was abated for years by the development and adoption of Bt corn. Bt corn is engineered corn with the genes of the bacteria Bacillus thuringiensis, poisonous to rootworm, inserted in it. With the adoption of Bt corn, introduced initially in 1996 to counter European corn borer and again in 2003 to counter rootworm, insecticide use on corn acreage fell from 25% in 2005 to 9% in 2010.
However, in the last several years, farmers and scientists have found rootworms with resistance to Bt corn. A study published in Proceedings of the National Academy of Sciences by entomologists at Iowa State University and the University of Illinois asserts numerous incidents in different states across the US of resistant rootworm. Initially, the rootworm was only resistant to one of the three varieties of Bt corn. However, scientists have now found resistance to a second variety as well. In addition, developing resistance to one variety increases the chance of developing resistance to a second. So the effort of biotech companies to create new genetically engineered seeds with “stacked traits” in one doesn’t seem like that good of an idea anymore.
To help combat the problem, scientists say larger refuges with non-Bt corn need to be planted as well as planting different crops year to year. While an advisory panel to the EPA back in 2002 said that 50 percent of each corn field should have only non-Bt corn, the biotech companies and EPA managed to merely recommend that 5 to 20 percent be dedicated to non-Bt corn.
Why It Matters
So what if insects and plants, viewed as pests and weeds interfering in our agricultural process, are resistant to our weapons against them? Can’t we just keep piling on more and more chemicals to deter them? Unfortunately, these chemicals take a toll on our environment and our health. Herbicides and pesticides have been linked to chronic kidney disease in Sri Lanka, developmental problems in children in California, and birth defects in Argentina. Furthermore, herbicides are blamed for the disappearance of the monarch butterfly and pesticides are suspected to cause Colony Collapse Disorder of bee populations.
Short-term benefits of killing “pests” on cultivated fields come with a price. When will we realize the price is too high?