Soybean board urges plan for resistant weeds

Defiant attitude to change | Soybean group advises proactive measures

SAN ANTONIO, Texas — The United Soybean Board has launched a campaign to combat herbicide resistant weeds in the United States, which are costing farmers billions of dollars a year.


“Herbicide resistance isn’t just a regional issue, it’s a national threat,” USB chair Jim Call said during a news conference at the 2014 Commodity Classic conference.


The Take Action campaign, which the USB is leading, is a joint effort by grower groups, seed companies and universities to promote a national unified approach to weed management.


There are 144 resistant weed species in the United States, according to the International Survey of Herbicide Resistant Weeds. Some of them are causing significant economic losses.


“A grower can all of the sudden need to spend anywhere from an additional $20 to $30 an acre,” said Vince Davis, extension weed scientist with the University of Wisconsin.


“In some real bad cases like Palmer amaranth, it may require expenditures of $150 an acre above and beyond what they were doing previously.”


He estimated that the extra expenses and reduced yields associated with herbicide resistant weeds are costing U.S. growers $2 billion a year.


Davis said part of the problem is that some growers refuse to change their agronomic practices. 


He witnessed that defiant attitude 12 years ago when working as a grad-uate student at Purdue University in Indiana, where glyphosate resistant horseweed or marestail was just starting to become a problem.


Davis developed extension material that shared his research findings with growers and advised them on how to deal with the problem. 


However, the material was largely ignored.


“So I have seen thousands of acres turn into tens of thousands of acres that turned into hundreds of thousands of acres,” he said.


Davis said the same attitudes exist in Wisconsin, where herbicide resistant weeds have become a problem only in the last three years. It’s why he believes a national branded effort for dealing with the problem is a good idea.


Jeremy Ross, extension soybean agronomist at the University of Arkansas, said Palmer amaranth is causing the biggest problems in his state.


“Because of that (weed), 80 percent of our growers that grow Roundup Ready are now using residual herbicides and 24 percent of our acres are in the Liberty Link system,” he said.


Growers have been pulling old cultivators out of tree thickets and restoring them so they can do row cultivation on their soybean crops.


“Just that one particular weed, Palmer amaranth, has really changed the way Arkansas soybean farmers, and I think farmers in the mid-south, are having to (farm),” said Ross.


Growers in some areas of Arkansas have resorted to hand weeding their cotton and soybean fields. Others are spending a lot of money on chemical control.


One grower spent $75 per acre on herbicide costs and was still unable to harvest two-thirds of his soybean crop because of excessive weed pressure. 


Ross worked with the grower the following year, changing his herbicide mix and encouraging him to plant Liberty Link soybeans. The new system virtually eliminated the farmer’s glyphosate resistant weed problem.


Davis hopes the Take Action campaign will deliver similar results for other growers who follow the agronomic advice. 


The main message is diversification.


“This includes diversification of effective herbicide modes of action, diversified weed management practices and also utilizing non-herbicide control options such as judicious tillage, cleaning equipment for weed seed and diversified crop rotations,” he said.


Davis had some thoughts for growers in Western Canada who are just starting to contend with herbicide resistant weeds.


“My advice to them is to take proactive measures,” he said. 


It will cost them a lot more in terms of yield and input expenses if they wait for herbicide resistant weeds to become a problem before reacting, he added.