GM Corn Failing to Control Corn Root Worm

Pesticide-resistant insects add insult to drought injury.

corn roots

Corn worms attack the corn roots, making them more susceptible to drought conditions.


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(Editor's note: We reprint this article with permission from Increasing evidence shows that genetically modified crops, manipulated to resist herbicides or to kill insect pests, create their own problems. Roundup Ready corn and soy, created to resist application of the herbicide Roundup, are evidencing stands of invulnerable weeds that the broad-spectrum herbicide no longer kills. And as reporter Tom Laskawy reports here, the bacillus Thurengiensis in GM corn apparently may no longer controls corn rootworm. If this genetically modified corn no longer controls the pest, the problem could have huge ramifications — not only are crops at risk, but farmers may not be able to buy enough non-GM corn to plant instead, since Monsanto et al. have locked up genetically modified seed lines. — MOTHER) 

Last winter, I wrote, in Grist, about evidence that one of Monsanto’s flagship GMO product lines — seeds engineered to produce the pesticide Bt — was succumbing to corn rootworms, the exact insects it was designed to kill. The evidence was somewhat thin — the Environmental Protection Agency (EPA) received reports from several states that indicated a problem — and certainly not decisive enough to prevent Monsanto from issuing an outright denial.

But now comes a report from Minnesota Public Radio (MPR) on the damage rootworms are doing to the current corn crop and the real concern farmers have that Monsanto’s seeds are no longer helping them control pests. The EPA is treating these latest reports seriously; according to the article, EPA officials visited some “problem fields” to observe possible evidence of resistance while awaiting results from Monsanto’s own scientists.

One pest expert MPR interviewed, Bruce Potter of the University of Minnesota, spoke more directly about the threat posed by rootworms, which appeared to have been held at bay by GMO corn until now. “We’re not going to make this go away … We’re stuck with managing this problem,” he told MPR. The report continues:

Potter has seen what he calls a “ridiculous” increase in rootworms apparently unfazed by the usually deadly protein [in GMO Bt seeds] in southern and western Minnesota this summer.

Potter also spoke at a workshop held on a farm experiencing rootworm resistance, where he said that Monsanto Bt seeds are “basically backfiring.”

“Instead of making things easier, we’ve just made corn rootworm management harder and a heck of a lot more expensive,” Potter said.

Of course, this is the summer of 2012, so a story about farmers in the Midwest wouldn’t be complete without a reference to the drought. And guess what? Droughts enhance and amplify the damage corn rootworms exact on crops:

In fields with a rootworm problem, the bug damages the cornstalk’s ability to absorb water just when it’s needed most. With the roots weakened, the plant can also be more vulnerable to wind.

Charlie Sandager, who hosted the workshop on his farm near the town of Hills in southwest Minnesota, said he learned last summer just how seriously rootworms can damage corn’s ability to stand.

“Strong wind came up and it just tipped the corn plants over like a big old tree,” Sandager said.

The sad irony is that farmers don’t need to transform themselves into organic farmers to keep their crops from being worm food — though that may be the best approach for developing more drought-tolerant fields. Historically, farmers managed corn rootworms through traditional crop rotations. These rootworms eat corn exclusively, so by alternating a corn crop with soy or another alternative, farmers would deprive the insects of food and the rootworm larvae would die off. This, by the way, is an age-old technique (originally part of the Native American Three Sisters agricultural tradition) that generates profits only for the farmer — not for seed companies.

Indeed, this abandonment of crop rotation was the other “innovation” of Monsanto’s Bt corn — aside from releasing its own pesticide, that is. Farmers could now grow corn season after season in the same field. At the time, it seemed like an amazing development to farmers across the country — and remains so to starry-eyed, tech-loving politicians and industry representatives.

For years sustainable agriculture advocates from Wes Jackson to Michael Pollan have decried farmers’ move to this corn monoculture, but not just for philosophical reasons. The danger of biotechnology and chemical-based agriculture as practiced today is the false sense of security it offers farmers. When you adopt Monsanto’s seeds and chemicals and “simplify” your farming, it seems like you’ve solved all your problems.

But what you’ve actually done is increased what finance-types call “tail risk,” which means in essence that all your assumptions about the chances something bad will happen to you turn out to be wrong. And probability being what it is, you can go a long time without disaster striking and then, when it does, you find yourself totally screwed.

Even so, it’s only taken about 15 years for GMO seeds to come onto the market, take it over, and then contribute to a crop failure such as this one. Of course, the rise of superbugs and superweeds came as no surprise to many scientists — molecular biologist Margaret Mellon of the Union of Concerned Scientists was warning about the possibility of Bt-resistant bugs as early as 2001; so don’t be fooled when Monsanto executives pull a Macaulay Culkin.

It’s tragic that it has taken a devastating drought to give farmers the full understanding of the risk of an over-reliance on a single crop and a single product line from a single company. The question is: What will they do in the face of this new reality? Will it be what one farmer in the MPR report felt forced to do this year — blow significant amounts of money on other, more toxic pesticides? Or will farmers consider returning to classic rotations or even organic methods? Growing less corn, perhaps, but providing profits to no one but themselves.

Tom Laskawy is a founder and executive director of the Food & Environment Reporting Network and a contributing writer at Grist covering food and agricultural policy. His writing has also appeared in The American Prospect, Slate, The New York Times, and The New Republic. Follow him on Twitter.

9/26/2012 5:05:48 PM

I think it is bad for our health and think you are wrong, It should be labeled .If it is as you say what are they scared of you have to label everything else.

t brandt
9/12/2012 4:07:51 AM

The Bt gene occurrs in nature. If you breath, you're exposed to it anyways. The scientists merely figured out how to put it in corn....Prior to WWII, US corn production was less than 30 bu/ac. The population of the world then was 2 billion. Now, thanks to technology, including GMO, we get 155+ bu/ac and the population is 7 billion. Should we go back to 30bu/ac?...And, BTW- the GMO corn is used for animal feed and industrial uses. You're not eating it.....The reason "why not" about labeling GMO is that it would imply there is something wrong with GMO. There has never been any evidence that GMO is bad for our health.... It would be smarter & cheaper to put the burden of proof on those who want their products to be certified as "GMO-free."

carmen ortiz
9/11/2012 11:51:57 AM

I would say, I'm sorry for those farmers but I'd be lying. We are being forced to eat the stuff because the FDA doesn't think we deserve to know what we are eating. I agree with Brian. As to t brandt, is he or she for real? If t brandt would have "been paying attention in hi school bio class, he would" know that is happening to corn is not natural and that there are many unforseen consequences to creating Bt corn, also known as Frankencorn. Mother Nature does NOT work that way. Genetically modifying plants and other organisms is as far as you can get from Mother Nature. What we DO NOT need is to make it even worse by doing what he/she suggest. Not all farmers are stupid, some actually use natural corn seed and natural methods that do not requiere genetically altered anything, especially not genetically altered seeds and the genetically worm that are the consequence of eating genetically altered plants for years. If the farmers he is "defending" were so smart they wouldn't be having this problem. If this commenter "is going to write about agriculture, perhaps he should" actually do some research. "He'd find it fascinating" and actually learn how it is possible to actually grow food without destroying the soil and living organisms (including humans). If he/she wants to eat genetically modified corn, which by the way pollutes conventional corn, resulting on farmers being sued by his people for allowing the corn to be polluted (I guess), that's fine but most humans do not want that, me included. So how about FDA starts ordering the labling of modified corn? No? Then answer why not. Oh, let me guess because people would not buy it.

brian jones
9/9/2012 10:23:37 PM

I dont look for the FDA to look out for the farmer in this situation. The head of the FDA works for Monsanto. The FDA seems to be concerned about Monsantos interests, not the publics interests.

t brandt
8/16/2012 9:49:22 PM

If Mr. Laskawy had been paying attention in hi school bio class, he wouldn't be so surprised now that root worms have started to show resistance to Bt corn. That's how Mother Nature works. It's called "Evolution." It doesn't mean we should never have tried to make Bt corn, but that we need to keep looking for the next genetic advantage to stay ahead of the root worm. .. He also writes implying that all farmers are stupid and make it a habit of following corn with corn. Few do, even with the recent financial incentives of the "ethanol mandate. They know that repeated corn crops might bring a short term gain, but that soil fertility fails in the long run, and farmers know they need to sustain that fertility with corn/bean crop rotation...If this author is going to write about agriculture, perhaps he should visit a farm once. He'd find it fascinating.