Rich Keller, Editor, Ag Professional  |   October 2, 2011 resize text

Seeing is believing when it comes to weed management failure, but farmers who haven’t seen the problems of glyphosate-resistant weeds in the south aren’t easily convinced that their fields could become eight-foot tall forests of waterhemp, giant ragweed and marestail.

“Farmers say they don’t see real problems, and they’ll wait until there definitely is a problem,” explained Chris Bahler, Lafayette, Ind., a Stine seed dealer and farmer in northern Indiana.

In northern Indiana, farmers are ignoring the warnings of hard-to-control patches of weeds and still spraying big weeds. “If they are late in getting into a field and the weeds are a little big, they’ll just up the rate of glyphosate and spray,” Bahler said.

Bahler is a believer that full-fledged glyphosate-resistant weed problems are just a couple years away; therefore, he is attempting to sell more LibertyLink soybeans and have farmers switch all their bean acres in one full swoop. “Unless they go 100 percent LibertyLink beans, it is a little more hassle keeping track of Ignite and glyphosate herbicide-tolerant fields, and because there also is the time necessary for clean up and wash out of spray equipment,” he said.

He also noted that Ignite has to be sprayed on three- to four-inch weeds, and large-scale farmers have fallen in love with the flexibility of post spraying bigger weeds with glyphosate. “With the bigger farmers who jump from area to area spraying fields, it is harder for them to time their post-emerge application exactly to smaller weeds,” Bahler noted. But he thinks they are on the edge of needing new weed management strategies.

Bayer CropScience has been conducting educational sessions about the use of alternative weed control to continuous glyphosate or any other herbicide use. One of the company’s main messages is that continuous use of any herbicide will lead to weed resistance to that herbicide.

The company’s Respect the Rotation program has received the support of weed scientists across the nation. “Respect the Rotation is an initiative to elevate the importance and grower adoption of herbicide diversity through rotation of crops, traits and modes of action. We are taking a very aggressive approach in trying to get guys to change the way they are thinking and to change the way they have been farming,” said Clark Jackson, Bayer technical sales consultant for southwest and south central Iowa.

Iowa farmers are not much different than those of northern Indiana in not recognizing the early warnings of a major weed disaster. He estimates that only about 20 percent of Iowa farmers are concerned enough about glyphosate weed resistance to change their weed control strategy next year or 2013, but it needs to be much higher.

Taking a group of ag retailers and farmers to a Respect the Rotation plot tour in east central Missouri really made an impression on Iowa attendees, waking them up to weed resistance being a bigger issue than they thought, Jackson said.

The goal is to break the continuous glyphosate use cycle so that the technology can be maintained for use where it is really needed and might even be useable every other year, especially in tank mixes. Using multiple modes of action herbicides in any one growing season; using a full rate of a pre-emergence herbicide when planting corn or soybeans; treating weeds post-emerge when they are small and won’t regrow to set seed heads; using alternative seed traits such as LibertyLink, which allows post-emergence spraying of Ignite herbicide; and even manual weed control and cultivating are basic concepts promoted in Respect the Rotation, explained Jackson.

For more information, Jackson can be contacted by e-mail at clark.jackson@bayer.com.

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