by Marion Nestle
May 5 2010

Oops. Weeds are developing resistance to Roundup

Yesterday’s New York Times ran an article disclosing the rise and spread across the United States of “superweeds” that have developed resistant to the herbicide Roundup.  The article comes with a nifty interactive timeline map charting the spread of Roundup resistance into at least 10 species of weeds in 22 states.  Uh oh.

Roundup is Monsanto’s clever way to encourage use of genetically modified (GM) crops.  The company bioengineers the crops to resist Roundup.  Farmers can dump Roundup on the soil or plants.  In theory, only the GM crops will survive and farmers won’t have to use a lot of more toxic herbicides.  In practice, this won’t work if weeds develop Roundup resistance and flourish too.   Then farmers have to go back to conventional herbicides to kill the Roundup-resistant weeds.

In 1996, Jane Rissler and Margaret Mellon of the Union of Concerned Scientists, wrote “The Ecological Risks of Engineered Crops” (based on a report they wrote in 1993).  In it, they predicted that widespread planting of GM crops would produce selection pressures for Roundup-resistant weeds.  These would be difficult and expensive to control.

At the time, and until very recently, Monsanto, the maker of Roundup, dismissed this idea as “hypothetical.”

I know this because in the mid-1990s, I traveled to Monsanto headquarters in St. Louis to talk to company scientists and officials about the need for transparent labeling of GM foods.  Officials told me that Roundup had been used on plants for 70 years with only minimal signs of resistance, and it was absurd to think that resistance would become a problem.  I pointed out that Roundup resistance is a “point” mutation, one that requires minimal changes in the genetic makeup of a weed.

As I explained later in my book, Safe Food: The Politics of Food Safety (the new edition arrives June 1):

From a biochemical standpoint, resistance to Roundup is not difficult to achieve.  Its active chemical, glyphosate, inhibits the action of an enzyme that makes three amino acids needed to construct plant proteins.  Plants cannot make the protein when the enzyme is blocked.  Bacteria, however, are well known to produce a mutant varient of this enzyme that is completely unaffected by glyphosate; they do so through “point” mutations (mutations that alter just one amino acid) or mutations that that cause the enzyme to be produced in such large amounts that glyphosate becomes ineffective.  Such mutations could occur in plants as well as in bacteria.  The transfer of Roundup resistance to weeks through pollination also is probable, and has already occurred.  The idea of widespread resistance to Roundup is not improbable, and it alarms the industry as well as environmentalists.  [Pages 183-184]

The Times article makes it sound like Roundup resistance is the end of the world.  It’s bad news for GM crops, but sure seems like another good reason why we need more acres planted in sustainable, organic agriculture.

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  • Cathy Richards

    They also didn’t believe that their seeds and pollen couldn’t travel more than a short distance so GMO crops could be contained, wouldn’t contaminate nearby fields, and would only affect local bees, insects.

    Right. Tell that to Percy Schmeiser, who was found to have not stolen the seed that drifted onto his fields from a truck, but was guilty of letting them grow.

    As a test once, to see how far seeds could travel when left on their own, I left some weed seeds and mountain ash berries in the sill of my car’s windshield and drove from Kelowna to Vancouver. Still there! 460 km. As was a little spider that had settled into his web nicely. Not scientific I realize, so maybe Monsanto is right after all??? Hmmmm….

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  • http://www.imthriving.com Lisa

    More and more bad news keeps coming up about Monsanto. I can only hope that justice and the “right thing” will prevail, eventually leading to the fall of this corrupt giant. I just hope it happens sooner than later before we are all contaminated.

  • http://www.antioxidants-for-health-and-longevity.com stan

    Monsanto is one corporation that needs to be run out of town before they destroy the world’s food supply – which they will if left unchecked. Out of a world of evil corporations, they might be the worst.

    Join the Organic Consumers Assoc.’s “Millions vs. Monsanto” campaign.

    http://www.organicconsumers.org/monlink.cfm

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  • Hugo X

    Finally the real risks of GMO is being discussed in the media. GMO is not a health issue but an ecological issue. Building new life forms (that are resistant to natural predators) and releasing them into an ecosystem that we do not understand will never be a good idea. How many case studies does it take of eg non-native fish being released in new environments and then taking over the eco-system?

  • http://www.StopBloggingAndCook.com Joy

    Monsanto is a monolithic force in so many countries, I wonder it it isn’t already too late to save the planet from the corn, soy, sugar beet and cotton GMOs from overtaking the world? They have too much unchecked power beginning with their control of the FDA. Ruining Indian farmers to the point of suicide is horrific evidence of a corporation operating with only thought for their own profits by a complete monopoly of plant life forms. Ironic that the business of feeding the world embodies such a total disregard of human life, isn’t it? Poetic justice of Roundup- resistant super-weeds.

  • LINDA

    DOES THIS MEAN THAT ROUNDUP MUST BECOME STRONGER TO ELIMINATE THE WEEDS? WHEN WILL IT ALL STOP! QUIT MESSING AROUND WITH NATURE. GO BACK TO HOW FOOD IS SUPPOSED TO BE GROWN!! WHAT WILL WE DO WHEN WE HAVE TO EAT THIS UNNATURAL FOOD BECAUSE NOTHING ELSE IS LEFT? I DONT WANT TO EAT THIS CRAP!! DO YOU? STAND UP AND VOTE EVERY TIME YOU BUY SOMETHING. DON’T BUY GMO AND PROCESSED FOOD–GO ORGANIC FRESH WHOLE FOOD!! IF WE STOP BUYING IT THEY WILL HAVE TO GIVE US WHAT WE WANT BEFORE IT IS TO LATE. POWER TO THE CONSUMER STARTS WITH YOU!!

  • http://www.antioxidants-for-health-and-longevity.com stan

    Hugo X: “GMO is not a health issue but an ecological issue.”

    If you believe that you haven’t done your research. There are potentially extreme health risks from eating GM food that are being covered up by Monsanto.

    http://www.seedsofdeception.com/utility/showArticle/?objectID=678

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