Twenty years ago, before genetically engineered (GE) foods were commercially available, one of the big concerns environmentalists had about the use of this biotechnology was that it would lead to “superweeds.”  Their concern stemmed from biotech products in the industrial pipeline at the time, like Monsanto’s Roundup Ready crops, that were impervious to various herbicides.  They pointed out that herbicide-resistant crops would encourage over-use of herbicides which could effectively “select” from among the weeds being doused with the chemical those that can survive and…voilà!…superweeds that can no longer be controlled by, for example, glyphosate, the active ingredient in Roundup.  (Some crops, like canola, also are related enough to various weeds that it is possible for them to produce “superweeds” simply by breeding with their weedy relatives.)

But, other scientists claimed, then and later, that evolution of Roundup-resistant weeds was a “negligible possibility” and the U.S. EPA and USDA allowed commercialization of GE Roundup Ready soybeans, corn, cotton, sugar beets, and alfalfa, as well as canola, anyway.

It took not much more than half a decade after Roundup Ready soybeans were commercialized before, according to The New York Times, a “superweed” showed up in a Delaware soybean field.  And now that approximately 90% of the soybeans and 70% of the corn and cotton grown in the U.S. are Roundup Ready, superweeds have infested millions of acres in at least 22 U.S. states.  And “super” versions of, for example, pigweed, horseweed, and giant ragweed that are glyphosate-resistant are posing problems not only in the U.S. but in agricultural areas of Brazil, Australia and China as well.

This is a serious situation.  It means that farmers in the midwest, south and east must spray their fields with more toxic herbicides in their efforts to protect their crops.  It also limits the use of no-till (or low-till) farming methods, methods that reduce erosion and runoff of pesticides and fertilizers into rivers, methods that were originally touted by proponents of Roundup Ready crops as a major reason to embrace these GE herbicide-resistant organisms when they were first commercially introduced.  Even Monsanto admits that the development of glyphosate-resistant superweeds is “a serious issue” although a Monsanto manager went on to tell The New York Times that this serious issue is, nevertheless, “manageable.”

But the primary way that Monsanto and other biotech companies plan to “manage” superweeds is by developing and commercializing GE crops that are resistant to additional herbicides, the idea being that such next-generation herbicide-resistant crops could then be doused with glufosinate or dicamba or 2,4-D (a component of the defoliant Agent Orange used during the Vietnam War), chemicals that should kill the superweeds that Roundup no longer can.

Sound familiar?

Environmental scientists have the same qualms now about these next-generation herbicide-resistant crops as they did about the first GE herbicide-resistant crops 20 years ago…only now the debate isn’t so hypothetical.  We now know, based on the rapid development of glyphosate-resistant superweeds, that genetically engineering crops to be resistant to additional herbicides will only lead to more superweeds.  Creating next-generation herbicide-resistant crops amounts to repeating the same mistake as was made with Roundup Ready crops…only this time around the herbicides that could be sprayed with abandon on the crops genetically engineered to be resistant to them will not be as relatively benign as Roundup (glyphosate).  (And let’s all hope that glyphosate is that benign because another consequence of spraying glyphosate on vast acreages of resistant crops is that, according to one study, it’s showing up in human urine samples; the details of this study are expected to be released later this year.)

Why make the same mistake twice (or three or more times as Monsanto, Syngenta and Dow Chemical are all developing next-generation GE herbicide-resistant crops)?  Haven’t we already learned the lesson that GE herbicide-resistant crops are not the way to sustainably manage weeds?  A more sustainable solution would be to use an integrated weed management (IWM) program instead.

[For more information on especially Dow Chemical’s 2,4-D-resistant crops, please see “Going Backwards: Dow’s 2,4-D-Resistant Crops and a More Toxic Future,” a publication of the Center for Food Safety.]