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Indiana producers have accepted biotech seed en masse. During the 2008 crop season, 96 percent of the soybean and 78 percent of the corn acres in Indiana were planted with hybrids containing one or more biotech traits. That equals more than 9.6 million acres of corn and soybeans.
To Bt or not to Bt
Purdue Extension entomologist John Obermeyer has witnessed the advent of biotech traits designed to resist damage done to corn by European corn borer and corn rootworm—the two most devastating corn pests. He says the introduction of Bt corn in the mid-1990s was a dream come true.
“Before the first Bt corn came along, the only thing that we could do to control corn borer and rootworm was throw an insecticide at them,” Obermeyer says. “With Bt we now had a tool in our integrated pest management toolbox that targeted a specific pest and left other insects, especially beneficial ones, alone. We’d always wanted to do that with insecticides but only had broad spectrum products.”
The Bt genes to control corn borer have been 100 percent effective. “That’s simply amazing,” Obermeyer says. “We’ve had it for more than a decade now, and, in both lab and field settings, we’ve not observed the corn borer developing resistance to the proteins. As a matter of fact, corn borer numbers overall have gone down in the past decade. There’s speculation that we’ve actually reduced the corn borer populations with this technology.”
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| Mark Evans, Purdue Extension educator in Clay and Owen counties, stumps for conservation tillage at field days and other venues. A no-till system can improve a soil's organic matter and lead to higher yields, he says. |
The Bt technology works like this: The proteins lie within the gene structure of the corn plant. When a corn borer or corn rootworm feeds on plant tissues above or below ground, the toxic proteins crystallize within the insect’s stomach lining. The chemical reaction causes the insect's stomach to rupture, resulting in the pest starving to death.
The big Roundup®
Weeds don’t munch on corn and soybean plants, but they hinder crop development all the same by robbing crops of sunlight, soil nutrients and water.
About the same time Bt corn made its commercial debut, Roundup Ready® soybeans hit the market. Roundup Ready® traits, which have since been incorporated into corn and other crops, permit the crops to survive applications of glyphosate, the active ingredient in Roundup® herbicide.
“With the soybean crop, we’ve more than doubled our no-till acres in Indiana since the introduction of Roundup Ready® soybeans in 1996,” says Bill Johnson, Purdue Extension weed specialist.
Roundup® applications haven’t dropped significantly since the Roundup Ready® debut, “But the use of atrazine, metolachlor, acetochlor—all surface water contaminants—has dropped fairly steadily as we’ve adopted more Roundup Ready® corn,” Johnson says.
Atrazine is the most-used herbicide on corn and controls a wide range of broadleaf and grassy weeds. The herbicide is being closely monitored by the U.S. Environmental Protection Agency because it has starting showing up in public drinking water. Atrazine has not been linked to health problems in humans.
While Johnson believes in the Roundup Ready® technology, he is concerned that overuse of Roundup® could lead to weeds that no longer respond to the herbicide. “I am concerned that genetically engineered crops could become pests themselves,” he says. “We’ve have issues like glyphosate-resistant bentgrass becoming an invasive weed, and now we’re looking at glyphosate-resistant volunteer corn in soybean crops. But if we’re going to feed the world, we’ve got to adopt the technology. We’re not going to feed the world with hand labor.”
Different is good
At his out-of-the-way Clay County farm, Mercer is happy to worker smarter, not harder. “Ever since I changed my farming practices in 1990, this farm has been a totally different place,” Mercer says, firing up his cerebral neurons again. “Grandpa would have to spend a few days here to see what we’ve done. He was the guy who plowed the ground behind a couple of horses.”
Contact Steve Leer
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