Is the value of Bt corn worth the technology fee? That's the question to consider if you've been planting Bt corn – and European corn borer infestations on your farm have been low, says a University of Minnesota economist.

"Corn borer populations in Minnesota and Iowa have been very low since 1998," says Terry Hurley, farm management economist with the U of M Extension Service. The 1997 growing season was the last year when borer populations were close to average (about one borer per plant in Minnesota).

Research shows an average value of about $16/acre for planting Bt corn in Minnesota. That's based on historical population trends through 1998. Assuming a technology fee of $10/acre, that leaves an extra $6/acre of profit, according to Hurley, Paul Mitchell at Texas A & M and Marlin Rice at Iowa State University.

"But if there are no corn borers around, there are no benefits to growing Bt corn," Hurley says. "The question that remains unanswered is whether Bt corn has changed these historical trends. If 50% of corn is Bt every year, that means 50% fewer borers in the next generation. And if you do that for a few years, borer populations become very small in a hurry."

"Some farmers who've been planting Bt corn may be in a situation where it becomes less valuable each year," Hurley concludes.