Electric Weed Control Showing Promise

The idea was to demonstrate electric weed control to participants at the 2023 Oregon Blueberry Field Day, July 26 at the North Willamette Research and Extension Center in Aurora. That didn’t happen, though, as the equipment was on the fritz.

Still, Marcello Moretti, associate professor in weed management for Oregon State University Department of Horticulture, was able to share some positive results from research he has been conducting.

Marcello Moretti speaks to participants at the Oregon Blueberry Field Day about research into electric weed control.

Particularly encouraging is the finding that when used at a typical operating speed, the electrical weed control equipment can be used in a weed mat system.

“We’ve been treating next to weed mat with good success,” Moretti said. “At a normal speed of one mile an hour to one and one-half miles an hour, we don’t damage plastic. And we’ve been having good success killing the weeds on the sides of the berm.”

Only when researchers slowed to one-quarter of a mile an hour did the plastic start to melt, he said.

“How effective it is depends on the weed species and the size,” Moretti added. “But we are seeing very good results with two applications at about a mile and half (an hour) spaced about four weeks apart.”

The second of the two treatments helps pick up any new flush of weeds that develop from weed seed beds between treatments, he said.

Moretti said the system also is showing excellent weed control in sawdust mulch systems and in bare-ground systems.

Moretti started researching electric weed control options in blueberries in 2021 with a machine that worked on alternating currents. Today he is using equipment that works on direct current.

“This is probably what we are going to see when this technology becomes more available,” he said.

The direct current system is a more efficient way to deliver energy, which helps improve weed control, save on diesel costs and requires less horsepower to operate. And it is less likely to ignite vegetation and melt plastic. The system, which runs on power generated from a tractor’s PTO, works by sending a high voltage current to plants that it contacts as it passes through a row, essentially burning a plant from the inside out.

Moretti said that among future plans, researchers now are assessing if the system is inflicting any negative impact on crop health and soil health. “In preliminary work we did last year, we saw no effect in the short term,” he said.

As for the demonstration he had planned, he explained that he needed to get a machine part from overseas to fix the equipment.

“We started with a rough morning,” he said. “We had a flat tire on the trailer and the equipment stopped working and so I decided not to push my luck.”

Still, Moretti said, the machine is showing promise for weed control in blueberries.