Corn Contamination Ahead

The percentage of transgenic corn hybrids increasing in Ohio may prove to make this season's planting more of a challenge.

Published on: Mar 5, 2008

According to the U.S. Department of Agriculture, over 40% of Ohio's corn acreage was planted to transgenic hybrids in 2007, up from 26% the previous year. Peter Thomison, an Ohio State University Extension agronomist, says that number is expected to increase this year, and could play a role in the dynamics of corn planting.

"How growers will be approaching the way they plant corn this year will be more important than ever, given the increasing acres of transgenic corn," says Thomison.

Transgenics is the science of introducing a gene from one organism or plant into the genome of another organism or plant. In crop production, Bt corn to control European corn borer and rootworm, and Round-Up Ready corn and soybeans for enhanced weed control would be examples of transgenics.

Thomison, who also holds an Ohio Agricultural Research and Development Center appointment, said that corn growers face the challenge of pollen contamination and planting refuges when dealing with transgenic hybrids.

"With the number of transgenic plantings increasing, there are implications for farmers who are growing non-transgenic varieties. One of those implications is preventing pollen contamination from transgenic hybrids," says Thomison.

Given the close proximity of non-transgenic fields to potential transgenic fields, Thomison says that growers might have a difficult time ensuring that their non-transgenic corn remains that way.

"Go out and talk to neighbors and find out when they are planting. Stagger planting dates and plant hybrids of various maturities," recommends Thomison. "Take steps now to make sure those non-transgenic fields are isolated."

Another challenge growers face is adhering to the concept of planting a 20% refuge within a transgenic field, specifically when using Bt corn hybrids.

"A refuge is simply a block or strip of corn planted with a hybrid that does not have the Bt gene. The primary purpose is to maintain a pest population that is not exposed to the Bt toxin, allowing susceptible insects to remain within the population and mate with any resistant insects that survive in the transgenic area," says Ron Hammond, an OSU Extension entomologist. "This allows any offspring to remain susceptible to the Bt hybrid."

Thomison says that planting a refuge is extremely important, especially with more and more growers jumping from non-transgenic hybrids right to triple-stack hybrids.

"It we are going to hold on to the value of these traits in the future, it's going to behoove growers to try and make sure they use a refuge," says Thomison.