Clearing Up the Confusion About Genetically Modified Corn

Learn more about the debate on genetically modified corn versus organic corn, and find out how to buy the best corn.


Learn more about the debate on genetically modified corn versus organic corn, and find out how to buy the best corn. Watch: A Farmer Explains What GMOs Are

Risking a rear-end collision, I braked and swerved into the gravel pullout of a roadside produce stand in our town. Deep-green ears of sweet corn were stacked like cordwood, the first of the year. I picked one up and peeled back the husk, sniffing the fresh, vegetal scent and salivating at the plump, pearly kernels.

"Is this local?" I asked the skinny, sunburned fellow who was pulling ears from a burlap bag. He averted his eyes. "Nope," he mumbled, "my cousin grew it over in Monkton." Monkton is the neighboring town, about three miles away.

His frankness could have been motivated by either honesty or self-preservation. No doubt some of his customers viewed the harvest from our town as far superior to anything grown in that other town. After I got back home, I gave the cobs a quick dip in boiling water and began devouring my first corn in nearly 10 months-buttery, sweet and rapturously corn-y-and felt no qualms about betraying hometown loyalty.

Americans take their sweet corn seriously: nothing says "summer" as eloquently as the crunch of kernels being gnawed off a cob. And there is merit to the purists' stance: the closer to your stovetop sweet corn is grown, the better it will be. A generation ago, corn dictated a strict locavore policy, long before the term was invented. In a day after being picked, half of the sugar in older varieties, such as Golden Bantam (introduced in 1902) and Silver Queen (1955), will turn into starch. That changed in the 1950s when John Laughman of the University of Illinois cross-pollinated three varieties of corn to create a hybrid strain that was not only sweeter but able to retain its sweetness longer. Laughman's work launched a saccharine revolution that has resulted in cobs that are up to five times sweeter than yesteryear's and can stay sweet for weeks, which means the supermarket industry loves the stuff. But by focusing on "sweet," breeders have neglected the other vital word, "corn," and the signature taste of summer is often muted in sugary sameness.

I wanted to know more about that corn my grandparents grew up on. So I went to visit Kevin Smith, who runs Sycamore Farms in upstate New York. To say that the buff 31-year-old's corn-growing roots run deep is an understatement; his father and grandfather before him made their livelihoods from fields of sweet corn. And it's not just any sweet corn. From the 237 acres that he tends an hour and a half north of New York City, Smith grows sweet corn for some of the most demanding palates in the country, including high-end Manhattan restaurants like Gramercy Tavern. Smith eschews the newest ultrasweet types of corn, instead growing varieties like Providence, Revelation and Delectable, which strike a perfect compromise, staying sweet longer but still packing plenty of real corn flavor. "I love everything about sweet corn," he says. "It's almost like nature's fast food. It comes in a neat little package. You just snap it off the stalk. There's nothing better." Smith often shucks a cob and eats it raw in the field for breakfast.

But a few years ago, Smith noticed a decrease in sales at his stand in Manhattan's Union Square Greenmarket. "I think my customers were lumping all corn into the same bucket," he says. "Field corn, sweet corn, GMO, high-fructose corn syrup... some people just gave up eating it."

There's a lot of confusion over corn. It's gotten a bad reputation due to what's happened with field corn, which is distinctly different from sweet corn. Harvested when its kernels are hard and dry, field corn is a commodity crop used in the manufacture of products like livestock feed, ethanol, high-fructose corn syrup, corn oil, liquor and all manner of processed foods: cookies, mayonnaise, margarine... Introduced in the mid-1990s, genetically modified (GMO) seeds now produce nearly 90 percent of the field corn in the United States (along with more than 90 percent of the soy and canola). Unlike hybridized plants, which are ­created through cross-pollination, genetically modified plants have strands of DNA added to achieve desired characteristics.

And in late 2011, DowAgrichemical upped the stakes with field corn by applying for permission from the FDA to ­market GMO corn that is resistant to 2, 4-D, an herbicide that was a component in the Vietnam War-era herbicide Agent Orange and is still used in many home lawn-care products. In people who work with 2, 4-D, the chemical has been linked to cancers, hormonal disruptions, reproductive difficulties and birth defects, according to the U.S. Department of Labor. In wheat-growing states where 2, 4-D and related pesticides are used in large quantities, the Environmental Protection Agency has found higher-than-normal rates of circulatory and respiratory birth defects.

Unlike with field corn, growers of sweet corn have been slow to plant GMO seeds. At approximately 700,000 acres, sweet corn occupies less than one-hundredth­ of the amount of acreage devoted to field corn in the U.S. Most is canned or frozen. The corn we eat fresh is grown on only 250,000 acres. Last year only 3 to 4 percent of the sweet corn raised in the United States came from the genetically modified sweet corn seeds Syngenta, a global agribusiness company, introduced 15 years ago. Monsanto hopes to change all that.

This summer for the first time, farmers are planting Monsanto's newly approved, genetically modified Performance sweet-corn seeds. Monsanto is aiming its marketing muscle at iconic corn on the cob. "Our sweet corn is a fresh-market product that will be sold on the ear." said Carly Scaduto, vegetable communications manager at Monsanto. She wouldn't divulge how much will be planted this year.

The new corn has been bioengineered to survive applications of glyphosate (sold under the trade name Roundup), an herbicide that destroys competing weeds. Planting "Roundup-resistant" varieties allows farmers to control weeds by spraying, an alternative to expensive and time-consuming­ methods like mechanical tilling. Monsanto has also spliced genes into the corn that produce toxins that kill corn-eating caterpillars, helping farmers reduce their use of pesticides. The poisons are derived from Bacillus thuringiensis (Bt), a bacteria that occurs naturally in soil and is approved for organic agriculture. Fatal to insect larvae, most experts say Bt is harmless to humans and animals. However, Cana­dian researchers reported in 2011 in the journal Reproductive Toxicology that they found residues of Bt in the blood of mothers and fetuses. "More research is needed. The impact of Bt on a fetus's development is unknown," says Aziz Aris, M.D., Ph.D., study principal investigator and professor in the department of Obstetrics and Gynecology at the University of Sherbrooke.

Although the FDA says that there is no material difference between kernels of GMO corn and those from traditional ­varieties, some recent research casts doubt on that conclusion. A study published in the International Journal of Biological Sciences in 2009 by a group of French scientists found liver and kidney damage in rats fed Roundup-resistant corn.

There are also environmental concerns around GMO crops. Weeds and insects can develop resistance to herbicides and pesticides like glyphosate and Bt, meaning that plants will have to be created that can withstand increasingly toxic chemicals. More than 26 species of weeds in 20 states are now resistant to Roundup. Similarly, the Environmental Protection Agency has found Bt-resistant corn root worms in four states. And because corn's pollen is easily transported by wind, conventional crops can be contaminated by neighboring fields planted with GMO varieties.

I asked farmer Kevin Smith about his take on GMO sweet corn. "I won't grow it," he said flatly. "If you want to avoid it, one way is to ask the farmers you buy from if they plant GMO corn." (Syngenta's Attribute and Monsanto's Performance are the two varieties sold in North America.) Another way: choose USDA organic corn. GMO crops are forbidden under organic standards.

Also, many farmers' markets (including New York's Green­market and San Francisco's Ferry Plaza) ban the intentional use of GMOs, so check to see if your market has a similar policy. In the U.S., genetically modified foods are not required to be labeled, but legislation is being considered in California and more than 20 other states that would require GMO labeling. (To learn more, visit

As for choosing the best-tasting corn, Smith abides by a self-imposed "one-day rule." He won't sell a cob that's more than 24 hours out of the field. Although corn lovers often profess to have favorite varieties, Smith says variety is far less important than freshness. Time is corn's great enemy. "Any corn can be ruined if it's old," he says.

In the height of summer, farmers' market stalls are overflowing, stands spring up along rural byways and even supermarket bins are piled with local corn. My biggest concern is not finding super-fresh cobs or avoiding GMO corn, it's overindulgence: moderation is not one of my strong suits when someone passes me a steaming platter of corn. Nor can I resist when it's cut off the cob and tossed into a simple summer pasta, a cheesy dip or even crab cakes. Fortunately, corn has its own way of enforcing discipline. The season passes quickly, and when there is no longer local corn available, I abstain. Happily.

Barry Estabrook's book Tomatoland delves into problems with modern agriculture.

Was this page helpful?
Related Articles