Why the Neighbors of GM Corn Farms See the Greatest Benefit

By Andrew Moseman | October 7, 2010 4:26 pm


Plant genetically modified corn, help your neighbor? That’s the argument of a study out in Science today—corn modified to keep pests away creates a “halo effect” that also reduces crop damage at neighboring farms that don’t plant the pest-resistant variety.

Bill Hutchison of the University of Minnesota led the study, which surveyed the records going back to 1996 for Minnesota and four other Corn Belt states: Nebraska, Iowa, Wisconsin, and Illinois. 1996 is the key year because that’s when farmers first planed Bt corn, a variety modified to produce a toxin that keeps away the European corn borer. As the name suggests, that insect is an invader from across the pond that likes to devour corn, and Hutchison and colleagues wanted to see how effectively Bt corn kept the pest at bay during the last decade and a half.

“We were surprised to find that a higher proportion of the total benefit is actually going to the non-Bt farmers,” says Hutchison. The reason for the conventional farmers’ windfall is tied up in the effectiveness of the transgenic crop. Not only does Bt maize suppress the corn-borer population in fields planted with the GM crop, it exerts a ‘halo effect’, lowering the pest population in conventional maize fields too. As a result, farmers planting non-GM crops benefit from fewer pests, but don’t have to pay the higher prices for the GM seeds. [Nature]

Why don’t the corn borers simply flock to the non-Bt fields and wreak havoc there? I called Hutchison, who explained: “The female moths can’t tell Bt corn from non-Bt corn” when they go to deposit their offspring. So, he says, imagine a section of land that’s 80 percent Bt. If the females moths distributed their young evenly across that territory, 80 percent would be in Bt corn, and they would die. “The same thing happens the next generation,” he says, which leads to an overall decline in borer population that benefits everyone. But because the non-Bt growers didn’t pay the premium for the modified seed, they received the greatest benefit.

[The scientists] valued the extra corn harvested because of the reduction in corn borer numbers and took into account the extra $1.7 billion farmers had paid for the GM seeds, equivalent to $10-20 per hectare. The total benefit was $6.8 billion but they found it was not evenly distributed: non-GM fields gained two-thirds of the total benefit, despite making up only one-third of the land. [The Guardian]

At the moment, 63 percent of U.S. corn is Bt; you can see the distribution in the map above. As for Hutchison’s example, he didn’t pluck the 80 percent figure out of nowhere—that’s been the highest percentage EPA has allowed farmers to plant because of worries that a greater percentage would lead to resistance in the borers.

The US Environmental Protection Agency has recently approved a “refuge in the bag” approach, in which a mix of 90% GM corn and 10% non-GM corn is sold. Previously farmers had to plant at least 20% non-GM corn. “As we transition to this, I do have concerns about long-term resistance management and sustainability of the technology,” Hutchison said. [The Guardian]

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Image: Hutchison et. al

CATEGORIZED UNDER: Environment, Living World
  • JenJen

    You know Monsanto is trying to figure out a way to charge non-customers for this alleged benefit.

  • Brian Too

    Hah, this is funny! I can just imagine the farmer’s conversation over the fence. “Hey Bill, what do you think about that Bt corn? I hear it’s pretty good! Maybe you should try some…”

  • fatkid

    Yeah, it really decimates those pesky Monarch butterflies too!

  • Georg

    Same thing as many vaccines: the “rest” of a population not
    taking part in a vaccination scheme profits from elimination
    of the big epidemy risk, without “paying” some maybe
    vaccination risk.

  • woaoo

    “$6.9 billion over 14 years”. Woaooo… Impressive !

    Just a question : is it a lot ?

    Not really, if we believe this french article, it represents only 2,7%…

    => http://www.lesmotsontunsens.com/les-ogm-ca-fonctionne-quoi-que-8081

  • jabyssal

    GMO’s hold a certain fascination with tech types but it is a complex issue, without perhaps a simple analysis from an environmental perspective, check this out from SciAm:

    Genetically inserted insecticide contaminates U.S. waterways

    By David Biello Sep 28, 2010


  • fatkid

    Wow #4- Maybe Paul Wakefield can make a legitimate comeback! Discredited Anti vaxer yesterday, Monarch Butterfly savior today. At least this time there wouldn’t be blood on his paycheck.

  • JD

    I hope they tested GM corn and found out it will not harm honey bees that pollinate it, or do they just take poison back to their hives? Is that why they disappear?

  • Ron

    Honey bees, monarchs, what else ? Maybe native prairie butterflies like the Poweshiek Skipperling, Ottoe Skipper which are now gone from MN.

  • zyl

    Please carefully read the data by the report (published by Science Magazine):
    About the percentage 63% of Bt-corn:
    It is a misleading number.
    That data is falsified by the USDA staff.

  • http://www.fajasshapewear5.co.cc fajas colombianas

    Maybe this is the reason why honebees are disappearing.

  • Joe

    You’re falsified zyl. That statement is just as logical as the one you just made. If you have supposed evidence of data being falsified, where’s the evidence for it, or rather why aren’t you in the process of getting the article retracted? You can make claims, but that doesn’t automatically make them believable.

    Fajas, the Bt varieties currently used do not target honey bees. There are plenty of studies going on that are double-checking that very issue, but Bt isn’t looking to be the magic bullet as to why bee populations are declining.

  • dave chamberlin

    Many of the commentators need to become educated on the differences between genetically modified corn, which is resistant to a herbicide and pesticides which are the killers of insects. Comments #3,8,9 and 11 are confused on the subject. Genetically modified does not = evil. I am not a shill for Monsanto, they are just another greedy corporation, but this whole Frankenstein type fear being peddled against genetically modified crops is getting ridiculous. Round up, the herbicide used on genetically modified crops quickly breaks down to safe chemicals, that is why they spray it on our foods.

  • http://www.spielegarten.com spiele

    You know Monsanto is trying to figure out a way to charge non-customers for this alleged benefit.


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