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Acres of GMO Corn Nearly Double in a Decade

Amy Mayer/IPR
The USDA reports that 93 percent of the corn planted in the United States contains a genetically modified trait.

Recent data from the U.S. Department of Agriculture says that over 90 percent of U.S. field corn is genetically modified, meaning the seeds have been embedded with a gene—usually from a bacteria—that  protects the corn from pests or herbicides.

That figure has nearly doubled over the past 10 years, from less than half of the total planted corn acres in 2004 to 93 percent this year (up from 90 percent last year). Soybeans have a slightly higher figure at 94 percent containing a genetic modification, but those seeds have been available longer. In 2004, already 85 percent of soybeans contained an engineered trait.

Iowa State University extension agronomist Mark Johnson says the leap in corn adoption is partly thanks to the success of the first genetically modified corn seed, which fought off a bug called the European corn borer.

“The first one was very, very, very effective,” Johnson said. “It’s what we call high dose. And so there’s never been any resistance found anywhere. And so that made the adoption of the other ones so much more rapid.”

Johnson says subsequent traits for corn rootworm and herbicides haven’t been as successful, leading to resistance in some pests and plants. He says there will always be some farmers who reject genetically modified seed.

“Some people are just philosophically opposed, some people don’t want to spend the money, some people realize it doesn’t make sense some times,” Johnson said. “And, in fact, some seed companies reported that their non-GMO seed sales went up this year.”

That’s a trend Johnson said may continue if the price of corn falls even more than it has already this year.

“If we see corn drop down to $3.25 a bushel,” he said, “people are going to look at those economics a lot harder.”

The more genetic modification goes into the bag—some seeds contain three traits—the more expensive the seed gets. But even if there’s some backing away, Johnson says genetic modification has rid the farmer of two of corn’s worst enemies. And that means GMO corn is likely here to stay.  

Amy Mayer is a reporter based in Ames