About the SA Blog Network



Opinion, arguments & analyses from the editors of Scientific American
Observations HomeAboutContact

GMO Bonus: Genetically Engineered Cotton Benefits Farmers, Predatory Insects

Email   PrintPrint

Bt-cottonCotton genetically engineered to produce a natural pest killer not only reduces the spraying of pesticides, but has also boosted the populations of beneficial insects, according to a new study. The study monitored the impacts of so-called Bt cotton over more than 20 years and 2.6 million hectares of farmland in northern China and found that transgenic pest control produced knock-on benefits for surrounding fields of different crops—a benefit for the more than 10 million small-scale farmers in the region who grow these crops.

Bt is a toxin derived from the bacterium Bacillus thuringiensis, which is lethal to the cotton bollworm (the primary pest in Chinese fields and a moth larvae) but harmless to other insects and animals, including people. To assess the impacts of this natural pesticide genetically engineered into cotton, scientists monitored 36 sites in six provinces of northern China from 1990 to 2011. They found that Bt cotton fields endured less organophosphate or pyrethroid insecticide spraying and thus boasted higher populations of ladybugs, lacewings and spiders—insect predators.

As a result, Bt cotton fields had fewer aphids—an insect pest not poisoned by Bt but nevertheless controlled thanks to the boosted populations of predators. That effect also spread to adjacent fields of maize, peanuts and soybeans. “The deployment of Bt crops may favor biocontrol services and enhance economic benefits not only in Bt crop fields but also in the whole agricultural landscape,” the scientists wrote in a letter presenting the research published in Nature on June 14. (Scientific American is part of Nature Publishing Group.) Crops engineered to produce the Bt toxin now cover some 66 million hectares of farmland globally.

In the U.S., similar research has found that Bt cotton not only reduces insecticide use, but also decreased the overall biodiversity in a given field. In addition, the protein crystal that makes Bt deadly—Cry1Ab—has been found floating in streams fed by runoff from agricultural fields. And, unfortunately, American pests like the western corn rootworm have been developing the ability to tolerate Bt, suggesting that resistance to the insecticide may become common unless measures are taken, such as planting non-Bt crops in adjacent fields.

Development of such resistance might prove a particular blow to farmers in China and the rest of the developing world as few alternatives to Bt exist to control the pests that plague their fields. In fact, a plague of bollworms in the early 1990s paved the way for the speedy government approval of the cotton genetically modified to produce the Bt toxin to cut down on the bollworms, insecticide pollution and farmer costs. Learning how to interweave natural control via predators such as ladybugs with the benefits of crops protecting themselves with the Bt toxin may be a key step on the road to a more sustainable agriculture.

Image: Flickr

About the Author: David Biello is the associate editor for environment and energy at Scientific American. Follow on Twitter @dbiello.

The views expressed are those of the author and are not necessarily those of Scientific American.

Rights & Permissions

Comments 9 Comments

Add Comment
  1. 1. marclevesque 5:24 pm 06/15/2012

    “And, unfortunately, American pests like the western corn rootworm have been developing the ability to tolerate Bt, suggesting that resistance to the insecticide may become common unless measures are taken”

    Increased frequency of pink bollworm resistance to Bt toxin Cry1Ac in China :

    Link to this
  2. 2. locus 2:05 am 06/16/2012

    Obviously GM engineers forgot to repeal the laws of natural selection!
    Example of 20th century thinking in a 21st C wrapper.
    Once the genetic pollutants are in the genome, how do you get them out again?
    The case against GM is not about food being safe to eat, its about the reckless manipulation of the genome, in which there is little understanding of the long term consequences. Seems we are doomed to repeat the mistakes of the past

    Link to this
  3. 3. mkass 3:51 pm 06/16/2012

    This article make statements and assumptions that have been severely challenged in scientific circles. The assertion that use of GM crops reduces pesticide use is false. Even Monsanto is recommending additional applications of competing pesticide products to counter the fact that weeds and pests are becoming immune to their products. There is actually an arms race underway between Monsanto and Nature and Monsanto is not winning. Furthermore, the assertions that these products are safe for humans is utterly unproven and highly questionable. The fact is that Monsanto either suppresses research into its products or hides information regarding this safety simply due to the fact that FDA and USDA rules do not require proof of safety. Weird but true. There is a growing backlash in this country against the monopolistic bent of the biotech industry and Monsanto in particular.

    Link to this
  4. 4. davidr 5:46 pm 06/16/2012

    In addition to the comments above, this article deals with only one study that was industry sponsored and not with the many other studies that are in conflict with it. In India alone the rising cost of seed (hundreds of times higher then just a couple of decades ago), requiring that small farmers take out high interest loans to plant their crops and the high rate of bt cotton crop failures has led to hundreds of thousands of small farmer suicides when their debt+crop failure leads to absolute destitution and the inability to to care for their families.

    Further this section of the story is alarmingly true. “In the U.S., similar research has found that Bt cotton not only reduces insecticide use, but also decreased the overall biodiversity in a given field. In addition, the protein crystal that makes Bt deadly—Cry1Ab—has been found floating in streams fed by runoff from agricultural fields.”

    GM/GE crops and seeds along with the heavy handed push to make them the dominant and eventually only available products in the the world food market also documents another concern an alarming increase in biodiversity in all markets where GM/GE seed/food dominates. A lack of biodiversity in potatoes types led to the infamous Irish Potato famine, the insects were blamed but with a greater diversity in potato crops including previous potato versions that were resistant to the insects, the famine would never have occurred but the dependence was on a single variety that became vulnerable.

    In fact loss of biodiversity with an emphasis on on only a few species out of hundreds being widely planted and the majority being patented GM/GE seeds/plants, poses probably the greatest threat to the world food supply bar none. The sad part is that a lot of this loss of diversity has been intentional to increase profits on a few key products, not accidental.

    Link to this
  5. 5. donnawanna 6:22 pm 06/18/2012

    SA continues to amaze w its support of controversial topics that represent the gov/agro/pharma hard line of profit.

    Link to this
  6. 6. Profitsup 6:22 pm 06/18/2012

    There is not a single living organism that is the same as it was a thousand or even a hundred years ago. Natural evolution as Darwin proved occurs and nothing man does will stop it or change it. the Universe changes every day = a asteroid could strike the earth next week that brings new life forms that could destory or alter all living plants or animals.

    We humans need to realize that “WE DO NOT EVEN KNOW WHAT WE DO NOT KNOW.”

    Link to this
  7. 7. tucanofulano 6:29 pm 06/18/2012

    Who got paid to write this piece of propaganda ?

    Link to this
  8. 8. Durazac 11:54 am 06/22/2012

    Well then, at least the readers are unbiased.

    I’m pretty happy with the GM stuff. As people covered in it’s results – meaning every one of you – you sure have a lot of doubts, but lack any real data at all, just speculation and complaint. To help you along, here is what you all seem to be missing:

    Of course things evolve – these tools we use are NOT MEANT to last forever. They are expected to be short term. The benefits are for the people living today and as we change, learn and grow, we’ll get better and create another that lasts for a little while.

    And to go after the study suggesting that it must be the result of evil industry? 20 years? 2.6 million hectares? Don’t mind while I chuckle.

    When you folks get on your computer created by the evil greedy capitalists of the computer industry, then your evil car, talk on your evil capitalist phones while covered in GM cotton from the evil cotton industry, take a moment to think how lonely, naked and in shape you would be, (if you could get enough food that is) without them. Ahhhh – already your mind leaps to the “we woulda’ had these things anyways” logic of yesteryear’s liberal. Yet the very universities that educate most of us run from taxes collected from the evil industries.

    Instead of griping about a study you don’t like, come up with solutions that work. It’s called “producing” and we evil industry capitalists excel at it.

    Link to this
  9. 9. rknight101 12:14 am 11/13/2012

    Myth: Genetically Engineered Cotton Benefits Predatory Insects

    Truth: Bt crops harm non-target and beneficial insects.

    Myth: Genetically Engineered Cotton Benefits Farmers

    Truth: Economic impacts of GM crops on farmers are variable

    Link to this

Add a Comment
You must sign in or register as a member to submit a comment.

More from Scientific American

Scientific American MIND iPad

Give a Gift & Get a Gift - Free!

Give a 1 year subscription as low as $14.99

Subscribe Now >>


Email this Article