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January 29, 2023

Study analyzes effect of genetically modified crops

By FERNANDO VICENTE | September 29, 2016

From soda to soup, crackers to condiments, it has been determined that more than 75 percent of processed food on our supermarket shelves contain genetically engineered (GE) ingredients.

In order to study the effects of these mass-produced GE crops, four economists — David A. Hennessy, GianCarlo Moschini, Edward D. Perry, and Federico Ciliberto — from Michigan State University, Iowa State University, Kansas State University and the University of Virginia, respectively, recorded farm data from 1998 to 2011.

The research encompasses more than 5,000 soybean and 5,000 maize farmers in the U.S. In comparison to other studies that historically use one or two years of data, the longevity of this novel research speaks for itself as comprehensive and prominent.

“The fact that we have 14 years of farm-level data from farmers all over the U.S. makes this study very special,” Ciliberto of the University of Virginia said in an article published in UVA Today. “We have repeated observations of the same farmers and can see when they adopted genetically modified seeds and how that changed their use of chemicals.”

Traditionally, farmers modified two genes in maize: an insecticide, in order to kill insects that eat its seed, and a herbicide-resistant gene. However, some crops, like the soybean, historically only receive the herbicide-resistant attribute.

According to the collected data, adoption of GE led to a consistent decline in the use of insecticides when farming  maize since 2000.

Both maize and soy crops, however, experienced an increase in herbicide use within the last five years, with the GE soybean farmers reporting a more severe upwards trend in the use of herbicide. These findings reveal that weed resistance to herbicides is starting to become an issue.

“Evidence suggests that weeds are becoming more resistant and farmers are having to use additional chemicals, and more of them,” Ciliberto said in a press release.

Even though the use of insecticides has decreased, the researchers commented that GE adoption for soybean herbicides can still have a significant, detrimental effect on the environment.

In fact, continued growth in herbicide use is a huge threat to the environment as such large doses of chemicals can decrease biodiversity and increase water and air pollution.

“Hence, the generality of their results is limited, and they cannot shed light on whether the impact of GE variety adoption on pesticide use has changed over time. In particular, there have been little data to assess whether the recent development of glyphosate-resistant weeds has eroded whatever herbicide use benefits there may have been from GT crops” reads the economists’ research article published in Science Advances.

The research becomes increasingly relevant with the invention and recent development of CRISPR-cas9, an efficient genetic engineering tool for gene modification. In contrast to the traditional GE crops, in which added genes can foster growth of herbicide-resistant weeds, the CRISPR-cas9 avoids the addition and enables the cutting or deletion of specific sequences.

With this invention, U.S. regulators are scrambling to catch up with the CRISPR technology. The U.S. Department of Agriculture has declared that it will not hold CRISPR corn to the same standards as traditional GE crops.

Nevertheless, the chemical giant DuPont Pioneer plans to advance the treatment of crops with this CRISPR-cas9 technology and bring it to market in the near future.

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