Nearly half of U.S. farms report having “super weeds”

A new studyfinds that 49-percent of all US farmers surveyed said they had glyphosate resistant weeds on their farm in 2012.  Glyphosate is the weed killer best known as the Monsanto product “Roundup.”

Giant Ragweed. Photo Frank Mayfield, CC some rights reserved

More than 70-percent of all corn, soy, and cotton grown in the U.S. is now “Roundup Ready.” That means the seeds are genetically modified to survive a spraying of Roundup.  In the mid 1990s, the early days of Roundup Ready seeds, it seemed to work really well for farmers.

They no longer needed to carefully apply herbicides only to the weeds; they could just spray the whole field. The Roundup would kill the weeds, but corn was “Ready,” it was resistant to the chemical, and survived.

In 2006, I walked through a Roundup Ready soybean field near Columbus, Ohio that was covered with giant ragweed.  The farmer was at wits end.  Weed scientists said the glyphosate was no longer working in his field, and the ragweed was taking over.  There wasn’t going to much of a soybean crop that year.

This new study by Stratus Agri-Marketing shows that 61.2 million acres of U.S. farmland infested with glyphosate resistant weeds in 2012.  That’s nearly twice as many as 2010.  (See Stratus graph.)

Graph: Stratus Agri-Marketing

The study also shows a greater variety of weeds are becoming resistant to glyphosate, and that these so-called “super weeds” are spreading geographically.

The biggest problems are in the South, with the mid-south and mid-west states catching up.  This may not be an issue in Northern New York at this point, but as more farmers get into commodity farming, this study is a warning that even a revolutionary seed technology like the Roundup Ready system has its limits, and should be used carefully.


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  1. The farm with a resistace problem may switch to a different crop and use one of the old pesticides to get rid of the weed or use cultivation in concert with the different crops.
    The over use of any pesticide risks the possibility of resistance. On my farm I have to be alert to resistance to parasite resistance to the wormers I use. I use a screening process and testing to determine the level of infection and resistance in my flock to avoid over use and to detect which medication is appropriate. This common practice on sheep farms today.

  2. Resistant organisms are certainly a concern which has to be addressed. It is important to mix time honored ag practices such as crop rotation and good husbandry with new technologies to gain the most benefit. The problem of resistance shows us the need for continued research and development both to find new technology and to refine our use of existing ones. It is not a reason to throw away several hundred years of progress. The agriculture industry will figure this out just as we have every other issue which has come our way. This type of discussion is valuable as it focuses us on refining our methods to keep most of the gains we have made, while finding ways to mitigate the problems.

  3. Anyone with a modicum of understanding of the mechanisms of the evolutionary processes by which living organisms are molded must recognize that there is no "silver bullet" herbicide which will function as desired from it's conception by homo sapiens until the Earth is consumed by the Red Giant phase of the Sun.

    Does anyone seriously believe that Monsanto scientists did not recognize that the "Roundup Ready" hype would have but a limited span of usefulness before the targeted audience, of unwanted weeds, would also become "Roundup Ready"? Did the upper management allow the marketing folks to tell the end users that their scientists estimated a useful "Roundup Ready" functional span of 20-30-40 years before the next "silver bullet" chemical elixir would be required?

    I reckon the "super weed" terminology is a tip of the hat to the "super bug" terminology bandied about by the medical profession in reference to the antibiotic resistant critters continuously being incubated within human chemical factories, with similar results.

  4. While large farms will worry, in my small garden the super-weeds fall before the hoe just like the rest. If only the super-germs would be so easy.