Chad Lee, Extension Agronomist
Researchers just published an article on the impact of Bt-corn in the corn belt in the October 8, 2010 edition of Science. They specifically examined Bt-corn with resistance to European (and Southwestern) corn borer. By examining insect counts in Bt and non-Bt fields along with production statistics, etc. the authors concluded that the benefits for using the Bt-corn was $6.9 billion to growers in Illinois, Minnesota, Wisconsin, Nebraska and Iowa over 14 years. Of that total, they estimated that $4.3 billion was for growers with non-Bt corn hybrids.
The benefits come with reduced European corn borer populations in Bt corn fields as well as nearby non-Bt corn fields. For example, in Minnesota, when only 40% of the corn acres were planted to Bt corn, European corn borer larvae declined by 73% over all corn acres. After calculating the estimated reductions in European corn borer larva, the authors also included the estimated yield losses from corn borer damage and the resulting yield increases from reducing the corn borer populations. The authors also included the difference in seed costs between Bt and non-Bt corn hybrids. A larger share of the economic benefit goes to growers of non-Bt corn because they are paying less for seed, but reaping similar benefits to their neighbors who raise Bt corn.
The authors did not include the cost of spraying an insecticide on non-Bt corn when corn borer populations warrant such an application. Once the cost of spraying an insecticide is considered, the economic benefits of Bt corn with corn borer resistance might be even higher to the producer.
The original article in Science is titled: Areawide Suppression of European Corn Borer with Bt Maize Reaps Savings to Non-Bt Maize Growers.
Another summary of the article can be found at: