Herbicide-resistant weeds are becoming more of a problem in Iowa. Plants including waterhemp, horseweed, giant ragweed and others are threatening the livelihood of farmers statewide, reducing soybean and corn yields and increasing production costs.

The Iowa Soybean Association (ISA) is committed to helping farmers understand and manage the problem and has recently launched a weed management action campaign called "Take Action." The multi-faceted effort, funded by the Soybean Checkoff, uses radio, video, print and on-line information to highlight and address the threat of herbicide-resistant weeds and the importance of taking action.

ISA has created a clearinghouse of information at www.iasoybeans.com/TakeAction/index.html.

The "Take Action" site features a tour of six Iowa farms, discussing the issue of weed management with farmers around the state, including Tom Oswald who farms near Cleghorn in northwest Iowa.

"It's not always about a product, but management techniques," he says. Farmers need to adapt management styles to their systems. While weeds in his area of the state are manageable now, Oswald says, "the issue of weed resistance has my radar turned on high."

"The ISA has the power to deliver," says Ed Anderson, ISA senior director of supply and production systems.

"Herbicide resistance isn't a new phenomenon, by any means. Farmers have dealt with it for more than 50 years, but the problem has intensified in the last decade as many weed species have become increasingly less sensitive to glyphosate -- the most widely used herbicide in the state. In some parts of the country, weed-infested fields have nearly put farmers out of business."

Mike Owen, Iowa State University Extension and Outreach weed specialist and agronomist, estimates 20 percent to 30 percent of soybean fields have glyphosate-resistant weeds --- 2 to 3 million acres. Less than 5 percent of the fields have serious resistance problems, he says.

"In the near future, that number is expected to increase dramatically," Owen says. It's likely all Iowa farms have resistant weed biotypes, he contends. Most farmers are just a year or two away from a serious weed control problem.

If farmers are proactive and adopt herbicide resistance management plans, glyphosate and other chemicals can still control weeds now and in the future.

To learn more about ISA, www.iasoybeans.com.