One touch from old sparky and the current brings down the curtain—death by electricity. Could electricides serve farmers as a weed killer?

“Electricity is the most viable source of weed-control energy,” says grower Kevin Olson. “I don't believe there are other real long-term options.”

Against a backdrop of agriculture's ongoing herbicide resistance issues and pesticide litigation, the use of electricity as a viable means of weed management in general row crops is gaining traction as both old and new technologies capable of sizzling weeds attract attention. RootWave combines a phalanx of cutting-edge electricide technology and aims for market entry in 2020. Lasco Lightning Weeder, an electrical discharge implement, is a late-1970s machine catching renewed interest from producers.

See & Zap

The attempt to harness electrical energy as a means to manage vegetation dates back to the 1800s. Railroads attempted to clear brush growth with charged wires, and agriculture researchers experimented with various rudimentary devices into the 1940s. The concept and theory of electric control was present, but successful mechanical transference to farmland was absent. 

However, the digital age has enabled technology to catch and pass supposition, according to Andrew Diprose, CEO of UK-based RootWave, who says electricides soon will be a common practice in weed management: “Beyond chemicals, people are desperate for another way to fight weeds and electricity is back on the agenda.”

Compared with other alternatives such as thermal and steam, electricity has major advantages, Diprose says. “No waste and no energy lost to ambient air or soil. The energy throughout the circuit treats the weed under the ground and boils it from the inside out.”

RootWave is partnering with Steketee on a pull-behind unit covering 8-12 rows using camera imagery to spot and zap weeds on the go, rolling at roughly 3 mph, with power sourced from the PTO. Essentially, visual recognition identifies weeds in real-time and RootWave makes contact with individual weeds to deliver a 5 kilovolt jolt (5,000 volts) with no soil disturbance.

The scalable unit serves all crop types and the voltage is flexible, Diprose explains. Initially, RootWave is targeting weeds up to 2”. “The fundamental technology in now in place so our next step is to scale and adopt the technology to treat mature weeds as well,” he explains.

Differences in silt loam, buckshot, heavy sand and general variations in soil types (and moisture content) sometimes require changes in voltage. There are also nuances with root type. “Fibrous or taproots aren't an issue, but a rhizome may require multiple passes,” Diprose describes.

What about microbial activity subjected to electricity? RootWave has undergone a series of agricultural environmental tests and Diprose says the results are promising: “The research is very positive, but we will get a definitive and scientific answer. We don't see it as a problem at all.”

And cost? “This will start as cost-comparable with herbicides, but in time, the potential is strong for a lower than chemical cost,” he adds. “There are basically no inputs other than capital depreciation.”

Brian Clevinger, co-founder of The Yield Lab Europe and managing director at Prolog Ventures, says electrical energy is a major draw for the farming industry. “There is an increasing swirl around resistance, costs and chemical litigation, and people are looking for innovation. A lot of people are looking into this technology and it could be a very, very big field. The need is huge.”

“Certainly there are general uses for RootWave technology in multiple spheres, but I think the average farmer could be using this product in a short time span,” Clevinger continues. “We're trying to help form partnerships to get this in the market. The technology is here and it's now an issue of getting people comfortable. Farmers want to be sure it works before they lay down money.”

Last Lasco Standing

In 1979, Kevin Olson was splitting time between his North Dakota corn fields in Grand Forks County and work as an electrical contractor when the Lasco Lightning Weeder was introduced in the region. Several potato and sugarbeet producers using Lightning Weeder units ran into mechanical issues and called on Olson's expertise. After successful repairs, Lasco's president caught wind of Olson's know-how, and within a few months, the Grand Forks grower was a Lasco dealer-distributor.

According to Olson, as of 2018, he is the last Lightning Weeder man standing and holds the rights to Lasco. Each year, he rents four units to soybean and edible bean growers spread across the Midwest (Illinois, Michigan, Missouri and Ohio) and has several units for sale.

“This technology is often unknown, but is amazing,” Olson describes. “It doesn't hurt the soil; we've tested a lot and never found any negative results. There's no damage to crops, and there are no safety issues for drivers.”

A metal applicator bar is charged with up to 14,500 volts of electricity, powered by a PTO generator. According to canopy height, the bar can be dropped to the ground or raised just shy of 4' high. Any vegetation contacted by the bar receives a full dose of voltage. However, Olson recommends reduced voltage (often a 30% drop) for early-season weeds, depending on moisture and dew (conductivity factors). “If you're running the bar over 5-6” weeds or less, you don't need full energy. Put 14,500 volts in small weeds and the power is so great you will carry a continuous arc that will destroy the crop. Later in the season, mature weeds get the maximum dose.”

Lightning Weeder has two models: 24' and 30'. The units can be front-mounted or utilized as a pull-behind. Olson suggests a tractor speed of 4 mph with low weed pressure; 2.5 mph with heavy weed pressure. “All this time and the Lasco is still very state of the art. There have been similar machines built, but they can't control amperage or voltage. To this day, Lasco technology holds so strong,” Olson says.

Spurred by renewed interest in electricides, Olson intends to restart the manufacture of Lightning Weeders. “I own the rights and I've been doing this since 1980. With a touch of the bar, the weed dies right down to the bottom of the root. Contact is death.”

Electric Avenue

Problems surrounding weed management have flipped the script on the potential of electricides, Olson says: “Herbicide issues are unrecognizable from what we dealt with as farmers 40 years ago. There are no two ways about it—the Lasco kills weeds and leaves behind no resistance issues. Electricity works and people are taking notice.”

Will weed-fighting machines wielding voltage be a common feature beneath equipment shops and sheds? Diprose believes row crop agriculture is on the cusp of weed-zapping options. “Mass acre farms will be able to control weeds with electricity,” he contends. “RootWave is going to be a common product across the farm world.”

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