Voracious Worm Evolves To Eat Biotech Corn Engineered To Kill It

Corn rootworm on the roots of a corn plant
Corn rootworm on the roots of a corn plant

Voracious Worm Evolves to Eat Biotech Corn Engineered to Kill It (Wired, March 17, 2014):

One of agricultural biotechnology’s great success stories may become a cautionary tale of how short-sighted mismanagement can squander the benefits of genetic modification.

After years of predicting it would happen — and after years of having their suggestions largely ignored by companies, farmers and regulators — scientists have documented the rapid evolution of corn rootworms that are resistant to Bt corn.

Until Bt corn was genetically altered to be poisonous to the pests, rootworms used to cause billions of dollars in damage to U.S. crops. Named for the pesticidal toxin-producing Bacillus thuringiensis gene it contains, Bt corn now accounts for three-quarters of the U.S. corn crop. The vulnerability of this corn could be disastrous for farmers and the environment.

“Unless management practices change, it’s only going to get worse,” said Aaron Gassmann, an Iowa State University entomologist and co-author of a March 17 Proceedings of the National Academy of Sciences study describing rootworm resistance. “There needs to be a fundamental change in how the technology is used.”

First planted in 1996, Bt corn quickly became hugely popular among U.S. farmers. Within a few years, populations of rootworms and corn borers, another common corn pest, had plummeted across the midwest. Yields rose and farmers reduced their use of conventional insecticides that cause more ecological damage than the Bt toxin.

By the turn of the millennium, however, scientists who study the evolution of insecticide resistance were warning of imminent problems. Any rootworm that could survive Bt exposures would have a wide-open field in which to reproduce; unless the crop was carefully managed, resistance would quickly emerge.

Key to effective management, said the scientists, were refuges set aside and planted with non-Bt corn. Within these fields, rootworms would remain susceptible to the Bt toxin. By mating with any Bt-resistant worms that chanced to evolve in neighboring fields, they’d prevent resistance from building up in the gene pool.

But the scientists’ own recommendations — an advisory panel convened in 2002 by the EPA suggested that a full 50 percent of each corn farmer’s fields be devoted to these non-Bt refuges — were resisted by seed companies and eventually the EPA itself, which set voluntary refuge guidelines at between 5 and 20 percent. Many farmers didn’t even follow those recommendations.

Fast forward to 2009, when Gassmann responded to reports of extensive rootworm damage in Bt cornfields in northeast Iowa. Populations there had become resistant to one of the three Bt corn varieties. (Each variety produces a different type of Bt toxin.) He described that resistance in a 2011 study; around the same time, reports of rootworm-damaged Bt corn came in from parts of Illinois, Minnesota, Nebraska and South Dakota. These didn’t represent a single outbreak, but rather the emergence, again and again, of resistance.

‘A widespread increase in trait failure maybe just around the corner.’

In the new paper, Gassmann describes further incidents of Bt resistance in other parts of Iowa. He also found rootworms resistant to a second variety of Bt corn. Moreover, being resistant to one variety heightened the chances of resistance to another. That means corn engineered to produce multiple Bt toxins — so-called stacked varieties — won’t do much to slow the evolution of rootworm resistance, as was originally hoped.

Farmers likely won’t stop using Bt corn, as it’s still effective against other pests — but as rootworms become more resistant, said Gassmann, farmers will turn to insecticides, thus increasing their costs and losing the ecological benefits originally gained by using Bt corn. As entomologists concerned by rootworm resistance wrote to the EPA in 2012, “When insecticides overlay transgenic technology, the economic and environmental advantages of rootworm-­protected corn quickly disappear.”

Entomologist Bruce Tabashnik of the University of Arizona called Bt resistance “an increasingly serious problem,” and said that refuge sizes need to be increased dramatically and immediately. He and other scientists have pushed the EPA to double current refuge requirements, but so far without success.

“Biotech companies have successfully lobbied EPA for major reductions in refuge requirements,” said Tabashnik.

Entomologist Elson Shields of Cornell University agrees. “Resistance was caused because the farmers did not plant the required refuges and the companies did not enforce the planting of refuges,” said Shields, who has written that “a widespread increase in trait failure may be just around the corner.”

In addition to increasing refuge sizes, farmers also need to vary the crops planted on their fields, rather than planting corn season after season, said Gassmann. Breaks in the corn cycle naturally disrupt rootworm populations, but the approach fell from favor as the high price of corn made continuous planting appealing. “Continuous corn is the perfect habitat for rootworm,” said Gassmann.

Shields also lamented the difficulty he and other academic scientists long experienced when trying to study Bt corn. Until 2010, after organized objections by entomologists at major agricultural universities forced seed companies to allow outside researchers to study Bt corn, the crop was largely off-limits. Had that not been the case, said Shields, resistance could have been detected even earlier, and perhaps stalled before it threatened to become such a problem.

“Once we had legal access, resistance was documented in a year,” Shields said. “We were seeing failures earlier but were not allowed to test for resistance.”

There’s a lesson to be learned for future crop traits, Shields said. Rootworm resistance was expected from the outset, but the Bt seed industry, seeking to maximize short-term profits, ignored outside scientists. The next pest-fighting trait “will fall under the same pressure,” said Shields, “and the insect will win. Always bet on the insect if there is not a smart deployment of the trait.”

10 thoughts on “Voracious Worm Evolves To Eat Biotech Corn Engineered To Kill It”

  1. Madness. Total greed, short sightedness and sure to add to the broken food chain……..
    Maybe the depopulation folks are right. What the greedy bastards don’t realize is that they will die, too. I only hope there is a special hell for these creeps, and I hope they crawl the underworld for eternity.

  2. In my line of work I deal with him corn everyday. This product was designed that all of the expression of the genetically modified trait would be gone by the time the plant enters the reproductive phase of growth. In layman’s terms, the later in the vegetative stage the less insect poison there is in the plant. The bugs were getting a small dose of it towards the end of the vegetative stage so the strongest survive and reproduce. All we did was push the rootworm beetles life cycle farther back into summer. Same amount of bugs, just later in the year. Make sense? That being said, we simply cannot grow enough organic food to feed 7 billion people. So. Starve quickly or take the gmo products and products that have been treated with insecticides. Plants are a living breathing organism that metabolizes chemicals. Think about it. If you took an antibiotic last year, do you really think it’s still in your system today? Or did your body metabolize it already? And as a side note. As someone involved in agriculture; those organic products aren’t as organic as you think. Whenever there is a system, there is someone willing to exploit it for a profit.

    • @cropchick,

      We can easily grow organic food to feed 15 billion people, but we cannot go on with our conventional industrialized agriculture.

      We are completely destroying our topsoil and are contaminating our environment.

      Not even (or better especially not) GMO crops will grow in such a soil.

      I know that organic products are not organic anymore (especially in the US, but also in Europe the standards have been watered down. In Europe people still can choose to buy Demeter & Bioland products which still uphold higher organic standards).

      We will either feed humanity organically or not at all.

      The following book is in German but it describes what is really going on:

      FOOD CRASH: Wir werden uns ökologisch ernähren oder gar nicht mehr Preis: EUR 19,99

      Have you looked up what GMOs and herbicides like Roundup do to our health?

      Even top scientists that created GMOs admit that we should not play around with GMOs the way that we do because we do not have the foggiest idea about the consequences and that we are all used as guinea pigs.

      You are completely brainwashed in my opinion.

      One day you will maybe wake up and realize who created GMOs and also understand their agenda.

      So good luck eating GMOs … you’ll need it.

  3. I am not brainwashed. I never stated that genetically modified foods were safe. As to feeding 15 billion with organic? I say prove it. I know for a fact you are looking at a 20% yield drag with organic food. Where genetically modified corn makes 200 bushel/acre, organic would make 180bu/A. Also. The food being labeled as organic; it’s not a matter of standards being watered down. I work in the industry. It gets sprayed with commercial products at times. Can it be tested and proven organic? It sure can. The plant has metabolized the chemical and there isn’t a trace left. Before you address someone as brainwashed, you should ask yourself if all organic farmers are any more honest than Monsanto. The answer is no. I said: Either we feed the world with imperfect food or you get high priced organic (which in the state of economy we are in most can’t afford even if there were enough of it) THERE IS NO UTOPIA WHERE EVERYONE GETS PERFECT FOOD. Are you such a fool as to believe there is a magic solution?

    • @cropchick,

      See my other comment.

      Conventional agriculture is also destroying the environment.

      If we go on like that we will not be able to feed the population because we are turning fertile soils into dust bowls and deserts all around the world.

      Conventional produce is only cheap because the price does not include all those ‘externalities’ (like the poisoning and destruction of the environment).

      If you include all those externalities into the price calculation then organic food will suddenly look cheap.

      But people want their cheap meat contaminated with GMOs, antibiotics, hormones, pesticides, herbicides, fluoride, mercury because it is sooo cheap, right?

      And then they get sick with cancer and die.

      There is only one solution to our problems in regards to our health and the environment and that is organically food produced in a sustainable way whether you like it or not.

      Call it Utopia or what you want.

      There is no magic.

      What appears to be magic is always based on knowledge.

      Those that do not have the knowledge call it magic.

      What I’ve said is possible, but not wanted by the elitists.

      If we don’t get it done billions will perish very soon, because what we are doing right now is unsustainable on so many levels.

      Next up is also the greatest financial collapse in world history and then food and clean water will be a big issue.

      It is perfectly OK for me that we both agree to disagree on that subject.

      Thank you for commenting.

      Infinite Unknown

  4. I have the perfect example of “organic” food. I live in millet growing country. Millet here is sprayed with 2,4-D, babble and grown on land recently sprayed with glyphosate. Now millet is a unique crop in that a farmer can store it for 12 years. Typically, farmers will sit on their millet and not sell it until it hits the high price. This happens every 10 years or so. Now in that 10 years that millet will be bought and sold on paper hundreds of times until it is impossible to trace where it actually came from. Then, it is sold as organic to the health happy fool in “organic” bread at twice the cost of the same bread a few feet down the grocery aisle. And don’t even get me started on the stuff that is sprayed and delivered in the same year. I am not brainwashed. I am inside the industry and I know how it works.

  5. @ Infinite,

    I appreciate your reply and your diplomacy. I would love to see the research concerning the “gmo’s kill fertility” They articles are vague as to specifically who did the research and where. I understand that they are testing humans and rodents. I just have one question and a serious one at that (not trying to pick a fight) How on earth are the millions of cows and other livestock not seeing the same effect? I work with ranchers and loosing a calf or piglet is emotionally and financially devastating to them. I know they would put two and two together and quite frankly; we do not see lessened fertility or tumors in any of the livestock here. I don’t understand what the difference is?


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