Humans today are fighting a losing battle against rapid evolution. We can see this in many circumstances, including the current COVID-19 pandemic. But, disease-causing viruses isn’t the only place where humans are struggling against evolution. Farmers across the country and the world are finding it increasingly difficult to kill weeds that were at one time easy to wipe out but have now became resistant to some of the industry’s most popular herbicides.
Using herbicides is the most efficient and cost-effective way for a farmer to manage weeds in their crops. Roundup is the most popular weedkiller in the industry. In the mid 1990s, “Roundup Ready” crops became popular and took the farming community by storm. Farmers were infatuated with the genetically modified seeds that were able to withstand glyphosate, which is the active ingredient in Roundup. However, after years of constant exposure, many weeds have also developed a resistance to Roundup. This prompted farmers to use more of the chemical, which has caused some weeds to become completely resistant to it.
Many new plants that are becoming resistant to herbicides are being discovered, and Roundup is not the only chemical they are resistant to. Maor Matzrafi, a researcher from the Department of Plant Pathology and Weed Research at Newe Ya’ar Research Center in Israel, has recently found new cases of herbicide resistance. Matzrafi explains in his article from Feb.that the “identification and characterization of new cases of herbicide-resistant weed populations play a key role in understanding the distribution and severity of this problem, and in mitigating failed weed control efforts. To identify and characterize these new cases of herbicide-resistant weed populations, Matzrafi and his colleagues conducted several field tests in different parts of the world. The results of these tests are concerning to farmers.
Matzrafi conducted a test on several Mediterranean weeds, all of which demonstrated resistance to the herbicides they used. One of Matzrafi’s colleagues conducted a test on a weed called Black Bindweed, which is an invasive plant in Kansas, USA. He found that Black Bindweed has a resistance to chemical inhibitors. The researchers also discovered the first glyphosate-resistant weed populations in Greece. Furthermore, the researchers found that chemicals sprayed on glyphosate-resistant corn in Brazil no longer had a significant effect on weeds that tend to grow in corn fields. This research suggests that there are many more herbicide-resistant weed populations than we previously thought.
To get a better understanding of how herbicides work and how weeds may become resistant to them, I spoke to Professor Muthu Venkateshwaran. Muthu is a professor of soil and crop science at the University of Wisconsin-Platteville, and also conducts research on soils and crops. Venkateshwaran explained that scientists genetically modify crops to be able to tolerate certain herbicides, and if these genetically modified crops cross-pollinate with a weed species, then the weed species could also develop a resistance to herbicide. As more and more weeds and crops cross-pollinate with each other, they can become more resistant to herbicides. This leads to major problems for farmers because they are not able to kill the weeds with the herbicides they are allowed to use.
There are a few solutions to the problem of herbicide resistance in weeds. To learn more about these solutions, I spoke with Professor Christopher Baxter. Professor Baxter is a professor of soil and crop science at UW-Platteville as well as a soil nutrient management specialist through the UW Extension. Professor Baxter talked about several techniques to help reduce the problem of herbicide-resistance. He explained that rotating herbicides of different target points, such as disrupting nutrient flow or reproductive systems, is very important. This helps because, if a farmer is using different herbicides, then the weed does not have as much of a chance to develop a resistance to that herbicide. He also talked about using other cultural methods rather than herbicides to control weeds. These cultural methods would include things like cultivating and mowing. Finding and using solutions to slow down and stop herbicide resistance in weeds is crucial.
Herbicide resistance in weeds is a major problem across the world in agriculture, and it is getting worse. Although there are currently many rules and guidelines that farmers are required to follow when using herbicides, more and more weeds are becoming herbicide-resistant. There is research being done to help address this problem. The agricultural community needs to work to find solutions for this problem so farmers can keep producing food and other necessities for the population.