GMOs false promises have led to resistant weeds, like this palmer amaranth, growing in a field of GMO crops.

Ask any executives at a biotech company like Dow or Monsanto why genetically engineered (GE) seeds are so great, and they'll tell you "They help the environment because farmers use less pesticides!" But they're wrong, and a new study published in the journal Environmental Sciences Europe shows just how wrong.

When GE seeds, genetically altered to withstand heavy doses of pesticides or long periods of drought, were first introduced in 1996, one of the main selling points around them was that they could either create their own insecticides, thus requiring fewer chemicals to kill bugs, or withstand one particular herbicide so that farmers wouldn't need to spray their fields with a chemical cocktail to kill weeds.

Sixteen years and millions of pounds of pesticides later, the technology has backfired says Charles Benbrook, PhD, research professor at the Center for Sustaining Agriculture and Natural Resources at Washington State University and author of the new study. "The increase in herbicide use is going up steadily, year to year," he says. Combining data from the U.S. Department of Agriculture (USDA) with computer modeling to make up for data gaps, he found that the overall use of pesticides has increased by 527 million pounds, or 7 percent, since GE crops were first planted in 1996. "Of course, this is expected and solely driven by the spread of resistant weeds," he adds.

Benbrook is referring to the massive and out-of-control problem of weeds that have developed resistance to Monsanto's Roundup, the main herbicide that GE seeds have been bred to withstand. These weeds can't be killed by Roundup and are so hardy they've been known to destroy farm equipment. "They're becoming a total nightmare for chemical farmers," he says. "Some farmers are starting to abandon their fields, which have become unharvestable because of the amount of weeds."

According to industry estimates, Benbrook says, these "superweeds" now infest two-thirds of farmland acres planted with Roundup-Ready corn, soy, and cotton. As a result, the USDA is considering approving GE seeds that are resistant to a much stronger, and far more dangerous, herbicide called 2,4-D; this herbicide is strongly linked to birth defects and reproductive problems in children and women living in agricultural areas.

Benbrook's study concluded that, because of the resistance to Roundup and the pending approval of 2,4-D–resistant corn, cotton, and soy varieties, the use of 2,4-D would increase by 50 percent by 2019. Even more concerning is the fact that 2,4-D could contain cancer-causing dioxin. Benbrook says that U.S. manufacturers of the pesticide have modern manufacturing procedures that control levels of dioxin, but their formulations are more expensive. If farmers turn to 2,4-D-resistant crops, they could turn to cheaper formulations of 2,4-D made in China and Turkey, countries where older manufacturing methods are used, which could mean high levels of dioxin contamination.

And what of the chemicals used to kill bugs? Those are likely to increase, too, he says. Although his analysis showed that insecticide use has decreased over the 16-year period he studied, insects, like weeds, are becoming resistant to biotechnology, particularly in corn. GE corn is bred to contain a relatively benign bacterium called Bt, which kills insects when they try to eat the corn and is even used by organic farmers (though not in GE crops, which are banned on organic farms), Benbrook says. "It's our safest natural insecticide." But thanks to overuse of Bt bacteria by biotech firms and widespread planting of Bt corn, cotton, and soy, insect pests like the corn rootworm are becoming as resistant to Bt, as weeds are to Roundup. 

That development could jeopardize nearly every farm in the country. "Bt is the absolute backbone of insect control in fruit and vegetable farming," he says.

Your move: Buy organic. It's the only way to support farmers who have rejected farm use of biotechnology—and its failed promises.

Photo: (cc) Agriculturede/Flickr