First of all, the reader has no idea what “vast” means or whether the Chronicle is referring to all herbicides, or just some. There’s also the question about where this information is coming from.

The USDA’s National Agricultural Statistics Service keeps data on pesticide use, but not in a user-friendly format that would allow a reporter to make easy claims about underlying trends. In 2009, The Organic Center issued a report titled, “Impacts of Genetically Engineered Crops on Pesticide Use in the United States.” It calculated that GE crops increased overall pesticide use by 7.5 percent between 1996 and 2008. That’s hardly a “vast” increase, and there are finer details worth mentioning.

While GE crops boosted herbicide use, they reduced insecticide use, according to The Organic Center, whose goal is a return to organic agriculture. Furthermore, while glyphosate use has gone way up, other herbicides have fallen by the wayside. The differences between those chemicals make simple claims about the relationship between the adoption of GE crops and pesticide use very difficult. According to the USDA’s Environmental Research Service:



Measuring pesticide use in pounds of active ingredient implicitly assumes that a pound of any two ingredients has equal impact on human health and/or the environment. However, the more than 350 pesticide active ingredients vary widely in toxicity per unit of weight and in persistence.

… Glyphosate has a half-life in the environment of 47 days, compared with 60-90 days for the herbicides it commonly replaces. The herbicides that glyphosate replaces are 3.4 to 16.8 times more toxic, according to a chronic risk indicator based on the EPA reference dose for humans. Thus, the substitution enabled by genetic modifications conferring herbicide tolerance on soybeans results in glyphosate replacing other synthetic herbicides that are at least three times as toxic and that persist in the environment nearly twice as long as glyphosate.

The Chronicle’s article missed this point. It also didn’t seem to understand that it wasn’t so much the “vastness” of herbicide use that created superweeds as overreliance on a single herbicide—glyphosate.

All of these details can be found in a 2010 report from the National Research Council called “Impact of Genetically Engineered Crops on Farm Sustainability in the United States.” Articles that kept a tighter focus on Dow’s 2,4-D-tolerant corn and the problem of herbicide-resistant weeds—such as one from The New York Times—did a much better job of explaining them.

Finally, as if all the forgoing problems weren’t enough, the Chronicle made passing reference to California’s “Just Label It” campaign for GE foods, which it described as “part of a nationwide drive to thwart the Obama administration’s expected clearance of” 2,4-D-tolerant corn.

One assumes that the drive to which the article was referring (it doesn’t actually say) is the Save Our Crops Coalition, a group of farm interests that worries that heavier use of 2,4-D would imperil their products. If so, it’s important to note that the coalition is worried about the herbicide itself, not the GE corn that goes with it. In fact, the group has repeatedly stressed that it “is not opposed to plant technology advances, particularly genetic modification.”

By trying to cram a hodgepodge of different concerns into a single article, the Chronicle ended up producing a slanted piece of journalism that failed to adequately explain any of them.

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Curtis Brainard is the editor of The Observatory, CJR's online critique of science and environment reporting. Follow him on Twitter @cbrainard.