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VIDEO: Study looks at shocking loss potential from uncontrolled weeds

Forty-three billion dollars is roughly the gross domestic product of Tunisia and the net worth of Oracle founder Larry Ellison.

It’s also the amount of money U.S. and Canadian corn and soybean farmers would lose annually to uncontrolled weeds if they couldn’t apply herbicides or use other control techniques, according to a new study by a group of weed scientists.

About half of the current average yield of both crops would be lost if weeds couldn’t be controlled, the study finds.

“I was somewhat surprised” to see such a large estimated loss, Anita Dille, professor of weed ecology at Kansas State University and chairwoman of the Weed Science Society of America’s Weed Loss Committee.

She led a team of experts from the Weed Science Society of America that studied weed loss data from 2007 to 2013. Other scientists involved with the study are associated with the University of Guelph in Ontario, North Carolina State University, University of Wisconsin-Madison and Washington State University.

Several reports from the 1980s and ’90s also looked at losses from uncontrolled weeds, but the weed science society wanted more up-to-date numbers, Dille says.

Corn and soybeans were selected for study because they’re the two most important crops financially, she says.

The impact of uncontrolled weeds on several other crops, including spring wheat, winter wheat and dry beans, likely will be analyzed later, she says.

The U.S. financial losses total an estimated $26.5 billion for corn, with losses of $3.25 billion in Minnesota, $1.5 billion in South Dakota and $740 million in North Dakota. The study assumes an average corn price of $4.94 per bushel.

Estimated U.S. soybean losses total $15.3 billion, with losses of $1.9 billion in Minnesota, $860 million in South Dakota and $823 million in North Dakota. The study assumes an average soybean price of $10.61 per bushel.

Estimated corn and soybean losses from uncontrolled weeds in Canada push the combined loss for the two crops to $43 billion. The weed loss committee used average commodity prices published by Statistics Canada and the National Agricultural Statistics Service, an arm of the U.S. Department of Agriculture.

Mixing it up

The study reinforces that farmers “need to do anything and everything to manage weeds,” Dille says.

That includes mixing modes of action and sites of action when using herbicides, she says.

Herbicides kill in different ways. Mode of action is the overall methods in which an herbicide affects a plant. Site of action is the specific process in the plant that the herbicide disrupts to interfere with its growth and development. Put differently, mode of action is “how” an herbicide works, while site of action is “where” it works.

Other weed-control strategies, including crop rotation and cover crops, also are important, Dille says.

Ag producers nationwide increasingly recognize the importance of using multiple weed control strategies, says Lee Van Wychen, Arlington, Va.-based science policy director of the National and Regional Weed Science Societies,

To read the report: