Claim:   U.S. farmers are saturating wheat crops with Roundup herbicide as a desiccant before each harvest, causing an increase in wheat-related ailments.


Example:   [Collected via e-mail, November 2014]

I read an article claiming that grain crops in the U.S., particularly wheat, are routinely sprayed heavily with roundup before harvest. This is done to promote a heavier crop, it says, but the toxic Roundup is absorbed by the grains and enters our food chain. I thought roundup broke down and became harmless in 24 hours, and wasn’t to be used on food crops.


Origins:   On 13 November 2014, the Healthy Home Economist web site published an article by Sarah Pope asserting that the reason people sometimes (but not always) experience digestive ailments after consuming wheat in the U.S. is because U.S. wheat farmers engage in “desiccation,” the practice of spraying wheat fields with Monsanto’s
Roundup brand herbicide (glyphosate) prior to harvest in order to ensure even ripening and easier harvesting:

The stories became far too frequent to ignore. Emails from folks with allergic or digestive issues to wheat in the United States experienced no symptoms whatsoever when they tried eating pasta on vacation in Italy. Confused parents wondering why wheat consumption sometimes triggered autoimmune reactions in their children but not at other times.

The bad news is that the problem lies with the manner in which wheat is harvested by conventional wheat farmers.

Standard, recommended wheat harvest protocol in the United States is to drench the wheat fields with Roundup several days before the combine harvesters work through the fields as withered, dead wheat plants are less taxing on the farm equipment and allow for an earlier and easier harvest.

Using Roundup as a desiccant on the wheat fields prior to harvest may save the farmer money and increase profits, but it is devastating to the health of the consumer who ultimately consumes those ground up wheat kernels which have absorbed a significant amount of Roundup!

First of all, anecdotal claims about “folks with allergic or digestive issues to wheat in the United States experiencing no symptoms whatsoever when they try eating pasta on vacation in Italy” are dubious to begin with (because they’re non-random, self-selected samples, not scientifically controlled and collected data) and allow for a wealth of unexplored alternative explanations (e.g., Europeans grow different varieties of wheat and process it differently than Americans do) aside from the one explanation the author has decided is the “true” one. Such claims are even more dubious when one considers that Italy actually imports about 40% of the wheat used in their pasta-making from other countries, including the U.S.

Additionally, the author’s claim that “According to the US Department of Agriculture, 99% of durum wheat, 97% of spring wheat, and 61% of winter wheat [in the U.S.] has been doused with Roundup as part of the harvesting process” is unsupported by documentation. Although glyphosate has been suggested for pre-harvest application in some places (such as Canada and Europe), the author appears to have confused a chart showing the overall percentage of glyphosate application wheat crops in the U.S. for one specifically detailing pre-harvest glyphosate usage on wheat crops. Those are two very different measurements.

Additionally, there appears to be some confusion in cited materials of the practice of desiccation and the practice of pre-harvest herbicide application, which are also two very different usages:

Q: Is there a difference between desiccation and pre-harvest herbicide application?

A: Yes, and the use is a matter of preference. True desiccants are harvest management tools that rapidly kill above ground growth of crops and weeds. This allows for rapid dry down and an earlier harvest. Desiccants will not give long-term weed control and any late moisture may cause both the weeds and the crop to start to re-grow.

Pre-harvest glyphosate application is generally used for perennial weed control. It can be used as a harvest management tool for dry down but the effects take much longer to appear. Pre-harvest glyphosate is a good tool for long-term control of perennial weeds such as Canada thistle, quackgrass, toadflax and dandelions.

Moreover, commenter after commenter with direct experience in wheat farming has chimed in to state that despite the author’s claims that nearly all the durum and spring wheat in the U.S. is “doused with Roundup as part of the harvesting process,” they’ve never engaged in, seen, or heard of such a practice and have no use for it because it’s unnecessary or economically unfeasible:

I grew up and still am around a farm that produces over 500+ acres of wheat and that is not at all how it’s harvested nor is that how it’s harvested in thousands of other acres around the state. Round up has no need to be sprayed before harvest and farmers don’t put anything on wheat months before harvest as it slows down the drying process in turn delaying harvest.

Our family has been wheat/cattle ranchers for generations. And we’ve never heard of anyone doing this and we ourselves sure don’t. We raise winter wheat on 2,000 acres in NW Oklahoma on the incorporated family farm. The wheat usually doesn’t need help to “die” so it can be harvested.

I am a farmer’s wife in central Kansas, and for my whole 36 years of life, and can assure you this is not a common practice. We are not an organic farm, and we do not use Round-Up on our wheat to kill it for harvest. Wheat ripens naturally on its own — the plants lose their green color and the heads tips down — usually as the summer heat comes on in June.

I know of no wheat farmer in the US that sprays glyphosate or RoundUp on their wheat. It is not a practice that is endorsed on our farm and would never suggest it to another farmer. Wheat close to the stage of harvest has already completed its lifecycle, so from an economic perspective it’s a complete waste of money to spray the crop.

Coming from a completely conventional farm family we also have never and know no one who has ever done this. It doesn’t make sense financially and that is the reason cited for doing it. Roundup is expensive as is the application especially as it would have to be done by air plane to avoid destroying the crop.

You are incorrect. My family farms and I can tell you for a fact that putting Round up on a crop ready to harvest is simply not done. Besides being a big waste of money (do you have any clue how much herbicide is needed for a 100 acre field? Or how much it costs a producer to apply it just once?), it makes no sense to apply it once the crop has lived its life cycle.

We ourselves surveyed a number of farmers in the Walla Walla Valley, which has been a large wheat-growing area for many years, and found none who had engaged in, or heard of, the practice of “desiccating” wheat with Roundup just prior to harvest. When challenged to provide evidence of her claims in this regard, the article’s author simply responded with petulance rather than sources and data:

Q: I’m a journalist covering agriculture in the heart of wheat country. I have never, ever seen or heard of a wheat farmer spraying his fields with glyphosate as a desiccant. Wheat’s natural life cycle allows for it to ripen in the heat of the summer so it naturally dries to an acceptable moisture level for harvest. Who was your source for the agriculture information you shared? I don’t know of any agronomist who would recommend the application of glyphosate 7 to 10 days before harvest.

A: Denial doesn’t magically make the problem disappear. Please do some research and see for yourself the truth about what the wheat industry is doing to the health of American citizens.

Glyphosate may see some usage as desiccant for wheat crops in the U.S., but support for the claim that 97% to 99% of all wheat in the U.S. is harvested in this manner is not documented by any source cited by the article’s author.

And as Alberta wheat country’s Sarah Schultz noted of the author’s claim that “when you expose wheat to a toxic chemical like glyphosate, it actually releases more seeds resulting in a slightly greater yield”:

The study that gets shared and starts misconceptions about glyphosate in farming stem from Stephanie Seneff, a very well known anti-GMO proponent, whom I’ve read about a lot in the last year. One of the reasons why my red flag goes up when Senneff’s name is behind research is that she’s a senior research scientist at the computer science and artificial intelligence lab at MIT with biophysics and electrical engineering degrees also from MIT. So why the research on pesticides from an electrical engineer/computer scientist? Truth be told, she and her colleague didn’t conduct any research at all.

Bloggers like Sarah Pope from The Healthy Home Economist have a big misunderstanding about wheat and glyphosate. She states on her blog after reading Seneff’s paper: “When you expose wheat to a toxic chemical like glyphosate, it actually releases more seeds resulting in a slightly greater yield.” This is completely false. The yield of the crop is already determined because the wheat has stopped growing — their job is done, the plant is dead. When the plant isn’t green anymore, that means photosynthesis cannot occur or transport nutrients. Spraying glyphosate won’t magically create more kernels of wheat that late in the game to create higher yields, however weeds are still growing which can take away from yields for next year’s crop.

Similarly, concerning the author’s assertions of how and why the glyphosate used with wheat is supposedly harmful to humans, another reader (a pharmacist) observed:

I would like to point out that the parts where you discuss CYP450 enzymes, gut bacteria, inflammation, toxins, diseases … well everything you mention with regards to life sciences makes no sense whatsoever. I have no idea whether glyphosate is toxic or not, so I can’t dispute that claim. However, your explanation of the underlying physiological notions is deeply flawed and inaccurate. You should have had this post reviewed by a scientist (biochemist, chemist, etc.) before it was published. Right now, this post is made of pseudoscience

Previous epidemiological studies on glyphosate “have not found associations between long term low level exposure to glyphosate and any disease”:

Early epidemiological studies have not found associations between long term low level exposure to glyphosate and any disease. Neither glyphosate nor typical glyphosphate-based formulations (GBF) pose a genotoxicity risk in humans under normal conditions of human or environmental exposures.

The EPA considers glyphosate to be noncarcinogenic and relatively low in dermal and oral acute toxicity. The EPA considered a “worst case” dietary risk model of an individual eating a lifetime of food derived entirely from glyphosate-sprayed fields with residues at their maximum levels. This model indicated that no adverse health effects would be expected under such conditions.

A 2000 review concluded that “under present and expected conditions of new use, there is no potential for Roundup herbicide to pose a health risk to humans.” A 2002 review by the European Union reached the same conclusion.

The most important point to take away from this article, however, is that it presents a flawed premise and doesn’t actually demonstrate any connection between current methods of wheat production and medical maladies in humans who consume it because:

  • The article does not document any recent increase in or unusually high level of wheat sensitivity in humans.
  • Even if an increase in wheat sensitivity were documented, that wouldn’t necessarily mean the phenomenon was due to a change in the production of wheat; it could simply mean that we are getting better at recognizing and identifying wheat sensitivities that have existed for a long time but previously went undiagnosed.
  • A documented increase in wheat sensitivity could have any number of environmental causes apart from the use of glyphosate in wheat production, and no causal connection between the two has been proved here.

Last updated:   15 November 2014