Production Blog

Weed Patch Lessons; Diversity is the Key

Pam Smith
By  Pam Smith , Crops Technology Editor
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Palmer amaranth isn't just a southern problem. Jason Norsworthy, University of Arkansas weed scientist, found this field of pigweed in Illinois. (DTN photo by Pamela Smith)

DECATUR, Ill. (DTN) -- The first article of my professional journalism career dealt with weed control in soybeans.

It was the spring of 1977, and the assignment took me to the University of Illinois offices of Marshal McGlamery. During that session, "Mac" talked about the importance of diversity.

We discussed weed evolution. He informed me that walking soybeans wasn't really child abuse (I spent a lot of time on the business end of a hoe growing up) but a darn good cultural practice.

I've thought about that interview a lot as I've traveled this country and around the world this past few years to learn more about weed control. It was also top of mind as I worked on the series on weed control that DTN will publish over the next couple of weeks.

Two summers ago, I watched University of Arkansas weed scientist Jason Norsworthy have a momentary flashback when he pulled into a weed-filled field near Belleville, Ill. His mission that day was to convince Illinois farmers that herbicide resistance was real. To his dismay, Norsworthy found the South's most vile weed already well-established and thriving.

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Since then, Palmer amaranth has been found in all the "I" states and is spreading.

Norsworthy's message that day was clear. "Folks, if you find even one escape, do whatever is necessary to destroy that plant and keep that seed from entering your seedbank. In our work, we've seen just one Palmer pigweed plant survive, and three years later, we couldn't put a cotton picker in that field. We completely lost that crop," he said.

Weed scientists worldwide are voicing similar appeals with the fervor of evangelists. More than 200 concerned scientists traveled to Perth, Western Australia, during February 2013 to debate the herbicide-resistant weed problem. As the only U.S. journalist in attendance at that meeting, I confess the depth of some of the science left me stuttering. However, the main message was clear: There are no simple solutions. Simple solutions got us here.

The Roundup Ready system spoiled us. It was easy, convenient and, over time, became inexpensive -- a potent combination that led to overuse. Although it was not the first herbicide to succumb to resistance, the sheer scope of the acreage involved has made glyphosate the focus of a lesson learned. Even more disconcerting is the growing number of weed species with resistance to multiple sites of action.

Our formula for writing a good crop-production article has always been to find something that helps farmers and report on it. When it comes to herbicide resistance, Ford Baldwin, another Arkansas weed scientist, tells farmers: "If you find something that works, change it. Keep the weeds confused."

That's a tough concept to carry out, especially when you add the challenge of devising a weed-control strategy that juggles contingencies such as weather. We also know cost ultimately drives nearly every decision.

The articles coming in the series titled "Weeds to Watch" cover the increasingly complicated task of controlling weeds -- resistant or not. You'll find an accounting by region of the most troublesome weeds. You'll learn about new equipment, new herbicides and why the answers to today's toughest weed problems won't come from a jug.

More than 30 years have passed since my first weed lessons with Mac. I can still hear his counsel: "The weed will always win. The secret to staying a step ahead lies in understanding its basic biology." That's a lesson we apparently have to learn. Again.

Pamela Smith can be reached at


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