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Published January 21, 2013, 09:51 AM

Survey says...

An North Dakota State University weed specialist says farmers slow to react to Roundup resistance.

By: Mikkel Pates, Agweek

FARGO, N.D. — Farmers in the Upper Great Plains have an opportunity to forestall an almost inevitable struggle with herbicide-resistant weeds, but most are ignoring the prophets and the reports from mid-South states like Arkansas.

Richard Zollinger, a North Dakota State University weed specialist, took an instant “clicker” survey of some 300 attendees at the 15th Wild World of Weeds Workshop at the Fargodome in Fargo, N.D. While he didn’t have time to fully analyze the numbers, he says the message is clear.

“People are still using a lot of reliance on glyphosate,” Zollinger says, summarizing the survey. “They’re not really using a lot of different modes of action and they just haven’t incorporated this mentality that it’s going to take more management and probably more money to do the same job that we used to do.” Most farmers are still using Roundup (glyphosate) followed by Roundup, he says.

The meeting included about 300 consultants, agronomists, county extension service agents and some chemical industry people. Only about 5 percent were farmers, Zollinger estimates. About 70 percent of those in the group were crop consultants and were reporting what their clients were actually doing.

The study preceded a keynote talk by Jason Norsworthy, a weed scientist with the University of Arkansas, based in Fayetteville.

Norsworthy explained how farmers in his region are beginning an expensive and difficult process of clawing out of some weed resistance problems with intensive management.

He says weeds have increased the complexity of weed control, have caused abandoned fields and have bankrupted some farmers. “It’s compromised conservation tillage for us,” he says, noting that one solution to some weeds is occasional moldboard plowing, to bury some kinds of seed that will deteriorate over time.

Norsworthy says the resistance to glyphosate will perpetuate overuse and weed resistance in other broadleaf herbicides.

“I honestly believe, as I look to North Dakota, and I look at kochia, and I look at waterhemp, you guys are heading in the same direction with those two weeds,” he says. Farmers would be “extremely naïve” to think simply rotating from soybeans to corn will solve their problem.

Among the tools Arkansas farmers are using to deal with the issue is a “Flag the Technology” strategy, where they put different colored flags in the field that identify different technology — white for Roundup, green for Liberty Link and red for conventional.

Other farmers are going to a “spray the dirt” program of scheduled applications before target weeds are detected by scouting, because they’ll inevitably be too late. They should use full-strength applications always and never partial-rates that add to the resistance problem. And they should not use early morning or late evening applications because weed leaves are pointed up or down, reducing spray effectiveness.

Soybean farmers in states like Arkansas are spending $60 to $65 an acre for herbicides and another $25 an acre for hand weeding to control weeds in soybeans, Norsworthy says.

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