UNIVERSITY PARK, Pa. -- Pennsylvania farmers whose crops have been plagued by European corn borer now can purchase corn hybrids that have been genetically engineered for resistance to the insect.
Other genetically modified corn lines coming on the market in the next few years may have even greater potential to benefit Pennsylvania growers, says an agronomist in Penn State's College of Agricultural Sciences.
"These new hybrids have a portion of foreign genetic material, typically from bacteria, inserted into their own," says Greg Roth, associate professor of agronomy. "Borer-resistant corn hybrids have genetic material from the bacteria Bacillus thuringiensis, or Bt, which produces a crystalline protein that kills the insects."
How well do these new varieties work? "To corn borers, they're deadly," Roth reports. "Research indicates that these transgenic crops kill nearly 100 percent of a European corn borer population, compared to an average effectiveness of about 60 percent for a typical insecticide."
The borer-resistant corn is more expensive than standard hybrids, but some farmers may find them worth the extra money. "Where a bag of premium corn that can plant about three acres might cost $90, the transgenic hybrid might cost about $120," Roth notes. "However, on average, fields with moderate to heavy corn borer pressure will benefit economically from a transgenic corn hybrid."
To assure a return, growers should target corn fields at risk. "The fields most likely to have corn borer problems are those planted very early, those planted very late, and those planted with longer-day hybrids," Roth says. "To see a consistent benefit, growers need to select high-yielding hybrids adapted to our area that have the Bt gene. Yield performance still needs to be our number one priority."
Some experts say these transgenic crops create the potential for corn borers to develop resistance to the Bt toxin with overuse. The registration of these transgenic crops includes a resistance-management program, so the amount of borer-resistant corn available to individual growers may be limited.
"Companies are mandated by the Environmental Protection Agency to monitor and manage insect resistance if they should see it," Roth explains. "If there is a significant outbreak of resistance, it's likely these products will be removed from the marketplace."
Even if that happens, other genetically modified corn hybrids will be on the market soon. "In a year or two, hybrids that control corn rootworm will be available," Roth says. "This will have a significant impact on both yield and reducing chemical costs, because a lot of corn is treated with soil insecticide to control corn rootworm damage. This will have even more impact on Pennsylvania growers than the borer-resistant corn."
Herbicide-resistant corns also are coming. "Hybrids that allow growers to treat fields with Pursuit, Poast Plus and Liberty herbicides will be on the market this year, and hybrids that let growers use Roundup probably will be available next year," Roth says.
"We also have high-oil corns, special corns for silage production, and, within a few years, possibly even corns that will result in fewer nutrients being excreted by cows or pigs, which could help nutrient management concerns," Roth says.
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EDITORS: For more information, contact Greg Roth at 814-863-1018 or send an e-mail message to Eston Martz Information and Communication Technologies Penn State's College of Agricultural Sciences 106 Agricultural Administration Building University Park, PA 16802 814-863-3587 http://aginfo.psu.edu/news/