The GM Grass Scare That Wasn't

Cows grazing in Tifton 85 grass/Source: UGA

On Saturday,  a CBS news reporter, Alix Bryan, posted a story out of Elgin, Texas about a herd of cattle poisoned by cyanide. The source of the poison, according to the story, was a "genetically-modified" form of Bermuda grass that was apparently generating the poison.

The problem was that the story was only partly right. The grass, called Tifton 85, was producing cyanide (more about that later). But it was not genetically-modified grass. Tifton 85 is a hybrid product - according to researchers from the University of Georgia agricultural research station in Tifton, GA (hence the name) it's been around since 1983 and it's a "highly digestible" warmth loving grass variety.

In other words, this was a 30-odd year old hybrid grass (in other words, a traditionally bred grass) not a lab-engineered variety as implied in the story. Scientists suspect that the ongoing combination of drought and heat in Texas may have caused chemical changes in the plants , leading to cyanide production. Cyanide, is, after all a naturally occurring plant poison.

But it won't surprise you to learn that it was the GM mistake - not the death of cattle in a small Texas town due to naturally occurring changes - that spread the story around the country. And what follows is a textbook study in what happens when a reputable news outlet like CBS is sloppy with scientific facts, especially relating to a contentious issue like genetically-modified crops.

Mostly anti-GM bloggers who took the faulty report at face value without bothering with fact-checking spread the story ( Tifton 85 is readily identified as a hybrid on-line.) Just to give you a couple of examples:

"Genetically Modified Grass Kills Cattle By Producing Warfare Chemical Cyanide" from Anthony Gucciardi at the Natural Society. I found this post repeated at numerous activist sites. I also noted more than 1,400 Facebook likes on the original post. And more than 1,000 on this one, "Genetically Modified Grass Begins Releasing Cyanide, Kills Texas Cattle" - from James Johnson at The Inquistr.

As Keith Kloor noted at his Collide-a-Scape blog, the error also got a boost from some  trained science communicators who tweeted too fast about the CBS story. Corrections and clarifications followed but, Kloor suggested, that part of the problem is that too many of us are just inclined to believe the worst about genetic-modification. That same reaction led David Tribe, at GMO Pundit, to write a piece called "GM Grass Linked to Texas Cattle Deaths by Fact-Free Reporting.

But that's really too blanket a criticism given the reporting that followed. Almost immediately, Linda Gentile at examiner.com posted a story titled, "GMO Food: Hybrid Poison Gas That Killed Texas Cattle Not Genetically-Modified."Other outlets took up the accuracy cause as well. Philip Bump at Grist wrote a sharp piece, "No, genetically-modified grass isn't killing cows with cyanide." And you could also watch the tone of the story shift, as illustrated by this piece from the Sky Valley News, "Hybrid Grass Linked to Texas Cow Deaths."

And, of course, CBS News ran this (unbylined) correction: "Grass tied to Texas cattle deaths hybrid, not GM."  The chronology of this, then, starts with a mistake, followed by criticism, followed by more research, followed by a fix from the original news outlet - which is actually a pretty good ending to the story.

-- Deborah Blum