As a proud skeptic I have always defended GM foods as a necessary and wonderful lifesaving measure. However, I recently found a study online about how the corn rootworm has developed a resistance to the GM pesticides and fears of ‘superbugs’ evolving are echoing across the net. I am always willing to change my mind in the face of new evidence, but I’m not yet convinced that this evidence is robust enough. Since you seem to be so great at getting in touch with scientists, could you dig up an etymologist or an agriculturist to set my mind at ease?
The first thing I did after I read your message was to email our entomologist pal, Bug Girl. Bug had this to say:
The study is legit–the problem is that people haven’t paid attention to refugia, and have created a situation where resistance is inevitable. Eventually, insects will become resistant to whatever we throw at them. We can, however, change our behavior to make that less likely.
Who or what is to blame?
The problem is not specifically the GMO corn crops themselves. Like Bug said, insects will eventually become resistant to whatever we try to use against them be that organic, genetically produced or chemical pesticides. The problem that we see happening with corn root-worms is happening in part because the farmers are not planting buffer zones of non-modified corn and/or they are not rotating their crops with soy or other vegetables.
This article from Western Farm Press goes into detail on the topic of insect resistance and corn crops and uses a pest called the European corn borer as an example. It was an earlier pest that threatened to destroy corn crops before GMO corn came onto the market. From the article:
In a 2010 paper in Science, Gray and colleagues from several Midwestern universities reported that the introduction of Bt corn in 1996 led to a profound and lasting reduction of the European corn borer across the upper Midwest.
This success was in large part due to two factors, Gray said. First, it was relatively easy to get high levels of the Bt proteins in above-ground corn tissues, on which corn borers feed. And second, regulators required farmers who used Bt corn to provide large buffer zones, called refuges, planted with non-Bt corn. The refuges would supply a lot of Bt-susceptible insects to mate with those that survived exposure to Bt and were thus resistant to the toxin, to reduce the development of Bt-resistant strains.
It would seem that the appearance of less bugs from high use of pesticides is proof that the crops are doing what they should by fighting off pests. The reality however, is that without buffer crops or rotating crops the insects that do survive, because they have developed a resistance to the pesticide, will interbreed and then create more insects with a high resistance. The buffer crops help because the non-resistant insects breed with the resistant ones and that can slow down overall pesticide resistance. Rotating crops can help as well because a pest that likes to eat corn probably will not like to eat soy and that in turn breaks or slows down the cycle.
There are also a lot of financial reasons why farmers are not planting buffer crops and overusing pesticides thus resulting in resistant insects. And it is not just the corn itself. Growers are adding additional pesticides to the soil as well as a sort of “crop insurance plan”.
From the Western Farm Press article again:
For corn in central Illinois, the average non-land costs – things like fertilizer, seed, crop insurance and machinery – come to about $513 an acre,” Gray said. Cash rent can add another $325 an acre for high-yield ground, he said. “So I think a lot of the growers see $20 to $25 dollars to apply a soil insecticide as pretty cheap insurance to protect that $850 investment.”
Landowners are raising rents in this competitive arena, some lenders encourage growers to do everything in their power to protect their yields, and federal incentives have lowered the cost of crop insurance for growers who use Bt corn, Gray said. So there are a lot of reasons for farmers to keep doing what they have been doing.
Rent and corn prices are high and it is not feasible for growers to switch crops each year.
It is not the genetically modified food that is solely to blame for resistant pests. It is important to be skeptical when people immediately blame the idea of genetically modified foods. It is very easy to point fingers when one doesn’t understand how a process works. And yes, as Harley mentioned above, GMO crops are indeed going to be more and more important as time goes on as we will need to feed more and more people. We as a society need to understand how to properly use these plants and not to simply throw out the technology because it is not a perfect solution.
In summary, it is a vicious cycle and the bugs and insects will do whatever they can to evolve and survive whether or not we grow plants with built in pesticides or whether we add our own organic or non-organic pesticides to the mix. Just remember that it is a complex issue and that GMO crops themselves are not where all the blame should be placed.
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*Corn photo by me.