USA - Southern Illinois University to test electricity as a weed killer

Date:07-23-2021

By Tim Crosby

Southern Illinois University Carbondale is collaborating on a project testing the use of electricity to control weeds in agricultural settings.

Karla Gage, associate professor of weed science and plant biology, is working with researchers  Mandy Bish and Kevin Bradley from the University of Missouri on testing The Annihilator 6R30 Weed Zapper, a patented, electric weed control unit mounted to a tractor. The multistate project is funded by the North Central Soybean Research Program with support from the Missouri Soybean Merchandising Council, who purchased the implement, and includes researchers from Iowa State University, University of Nebraska, Kansas State University and Purdue University.

With certain weeds becoming increasingly resistant to traditional herbicide management, farmers and agriculture researchers are taking another look at the practice of electrocuting weeds, which railroad companies used as long ago as the 1890s. Those companies, however, eventually turned to fire and eventually to herbicides, once those became available.

“Herbicide resistance is especially problematic in agriculture, and there are over 20 species in the North Central soybean production region that are confirmed as resistant to at least one herbicide site of action,” Gage said. “Growers are looking for new weed control tools to use.”

Two of the most problematic species in Illinois and the extended soybean production region are Palmer amaranth (Amaranthus palmeri) and waterhemp (Amaranthus tuberculatus), Gage said.

While electricity is one alternative, another option SIU researchers are exploring is called harvest weed seed control. In that method, weed seeds are managed or destroyed before they go back into the soil seedbank to germinate the following season.

SIU researchers also are exploring the use of inter-row cultivation and other non-chemical weed control methods. Keeping in line with the proposal’s exploration of non-chemical weed control methods, SIU will be looking at a comparison treatment of inter-row cultivation to remove weeds.

“This will be done alone and in combination with the Weed Zapper,” Gage said. “Electrocution has again become a potential tool.”

In the case of The Annihilator 6R30 Weed Zapper, the equipment researchers are testing, two or more tool bars are mounted to a tractor, with each containing an electrode. The bars contact weeds that have grown above the soybean crop canopy and electrocute them. Just 65 to 130 milliseconds of the proper amount of current can cause them to die.

Research with the Annihilator 6R30 Weed Zapper began in Missouri in 2020 with focus on weeds common to Missouri soybean producers.  But many questions remain with the method and how effective it will be across geographies and weed species.  The influence of a plant’s specific biology – factors such as its leaf orientation, cuticle thickness and the location of its growing points – will likely impact effectiveness.

“All this may have an impact on the feasibility and effectiveness of electrocution,” Gage said. “The study seeks to answer many of these questions.”