QI read NY Times articles about a super pigweed growing in response to Roundup Ready cotton. As a result, according to the article, Monsanto was actually purchasing more toxic herbicides for the affected farmers. So the purpose of Roundup Ready (to limit

I read NY Times articles about a super pigweed growing in response to Roundup Ready cotton. As a result, according to the article, Monsanto was actually purchasing more toxic herbicides for the affected farmers. So the purpose of Roundup Ready (to limit the use of highly toxic herbicides) was defeated by the expected adjustments of natural selection. Aren't we playing with fire by introducing unpredictable changes to the environment?

AExpert Answer

Your question is a good one, and I can see the reason you would be concerned.  Let me share a few facts that are not forthcoming from many of the articles and blogs written on this topic.  Hopefully, you will see that the core issue is less about reasons for or against Roundup Ready crops and is more about using technologies to promote a more sustainable agricultural production system.


Over the past several decades, farmers and agricultural scientists have come to the following conclusions regarding weed management:


  • Resistance is common to most herbicides and is not just an issue with glyphosate. The emergence of resistance relates to how an herbicide is used in a weed-management system. Additionally, herbicides do not cause resistance but rather select for individual plants in a population that contain a gene that is naturally resistant to the herbicide; consequently, the plant is not killed by the herbicide.
  • The way to manage resistance to herbicides and any pesticide or pest-control practice (even those that are not related to chemicals) is to use two or more control methods with overlapping activity. In some cases this means using more than one herbicide that targets the same weed. So, in the case of the so-called super pigweed in Roundup Ready cotton, populations resistant to glyphosate did evolve due to the exclusive/sole use of glyphosate by farmers to control this weed over many years. When a farmer is dealing with glyphosate-resistant weeds in a field, academic and industry experts recommend using other herbicides and, in some cases, to combine use of different herbicides with nonchemical weed control options. In fact, academics strongly recommend that farmers who are not dealing with resistant populations to proactively use these same basic techniques to prevent establishment of resistant populations in the first place.
  • If farmers elect not to use multiple herbicides to manage weed resistance, they will have to use more mechanical tillage and/or hand hoeing, which have environmental consequences. For example, increased mechanical tillage can increase soil and nutrient runoff and may increase pollution of our rivers and lakes.
  • Lastly, all herbicides recommended by university, government and private-sector scientists have been  approved by the U.S. Environmental Protection Agency. U.S. regulation  of pesticides provides assurance that approved products can be used safely. 
  • There are distinct environmental advantages of using herbicides for reducing tillage, lowering greenhouse gases and reducing run-off, as well as improving agricultural production and management efficiency. We will truly be playing with fire if we do not continue to use the best science to address herbicide resistance, because fewer new herbicides and loss of herbicide effectiveness due to resistance will ultimately threaten food security and the environment. 
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