Research Highlights

Managing Resistant Weeds with Seed Destruction Technologies

By Barb Baylor Anderson

Controlling weeds like herbicide-resistant waterhemp and other pigweed species is a serious economic challenge for soybean farmers. Rather than wait until all herbicide options become unavailable, weed scientists are evaluating non-chemical control options now.

“Postponing non-chemical weed control research until all available chemical control options have been exhausted would be a mistake and would leave producers with a lack of weed control options and even more serious herbicide-resistance issues than producers currently face,” says Kevin Bradley, University of Missouri Extension weed scientist. “That is why we are looking at non-chemical weed control options now so they will be ready when they are needed.”

With funding from the Missouri Soybean Merchandising Council, Bradley is in year two of a project evaluating weed seed destruction options with an implement called the Seed Terminator (www.seedterminator.com.au/), which makes weed seed unviable by pulverizing it before it exits the combine. Bradley began the first year of research with WeedZapper (theweedzapper.com/) also, an implement that electrocutes weeds and keeps them from producing seed.

“Any tool that keeps weed seed from returning to the soil is valuable for U.S. farmers. These implements will clearly have a fit in the future and we just need more research and perhaps modification to make them more suitable for our U.S. conditions and weed problems,” he says.

The Seed Terminator concept was developed in Australia to destroy resistant ryegrass. Weed seed is “chewed up” by the on-combine implement so it can’t grow. Bradley has found more than 98 percent of waterhemp and nearly all other weed species seed is destroyed. But he is working on some of the kinks, including that green weeds with high moisture content are difficult to destroy and there is some degree of header loss and thresher loss of weed seed.

Simultaneously, Bradley is investigating when cereal rye is used as a cover crop, what the seeding rate should be to reduce waterhemp emergence. All of the Missouri research is being validated in both greenhouse screens and field trials and eventually may be shared in field day demonstrations. Bradley plans to keep the non-chemical weed control trials going in the same location to better understand the long-­term benefits or costs associated with the technology.

“We will probably be able to give some pretty definitive recommendations about seed destruction technologies after our second year of research at the end of 2020 harvest. For weed electrocution, 2020 was the first year of research so we may have initial impressions,” he says.

 To learn more about Seed Terminator technology history and use, watch this webinar from the checkoff’s Take Action series, www.youtube.com/watch?v=SmrsiRbe318&feature=youtu.be.

Published: May 18, 2020