Herbicide Use in Corn: Treated (L) Untreated (R)

In southern states, corn is often planted in a three-year rotation with peanuts and cotton. One of the values of having corn in the rotation is that effective herbicides that are used in the corn crop control populations of weed species that would be difficult to control in the peanut and cotton crops. Thus, the control effectiveness of the corn herbicides benefit the succeeding peanut and cotton crops.

“Corn in a Deep South crop rotation remains one of the best weed management tools or decisions a grower can make – when he can make it. A corn crop squeezed into a field at least every three years in a corn-cotton-peanut cycle is most effective.

“There is an inherent value to a good crop rotation that is likely priceless, especially in the long-term weed management of a farm,” says Eric Prostko, weed specialist with the University of Georgia Cooperative Extension.

For corn particularly, its arsenal of herbicides is a welcomed addition to fields, he says, noting that most common field corn herbicide programs farmers use all give similar weed control results.

“But for one big reason, corn is the only major crop we grow where we don’t have to use a PPO (protoporphyrinogen oxidase) herbicide. Atrazine is carrying the load for us with corn” he says.

That herbicide’s economic, broad-spectrum weed control is certainly a plus, but the biggest benefit it brings to fields in the Deep South is its control of pigweed – a problem that isn’t going away.

For south Georgia farmer Philip Grimes, the atrazine-glyphosate one-two punch that his corn rotation provides is essential to his management of herbicide-resistant pigweed that showed up on his farm a couple of years ago.”

Author: Haire, B.
Affiliation: Reporter
Title: Corn in rotation a strong weed management tool
Source: Delta Farm Press. 2014-01-17.