U.S. Midwest company unveils new model of weed electrocutor

Long before green-on-green and green-on-brown spot-spraying technology, a company from Ottertail, Minnesota, offered its own weed control solution: electrifying them once they breach the plant canopy.

Lasco Inc. has been producing the Lasco Lightning Weeder since the late 1970s. Since then, it’s gained the attention of organic farmers throughout the U.S. Midwest.

Why it Matters: With no end in sight to herbicide resistance, electrocution of weeds is another alternative to progressively more expensive chemical crop protection products.

The company is marketing its latest model — the LW-10 — for use with larger tractors than previous versions could accommodate.

The weeder, which requires a tractor with a minimum of 130 horsepower, works through a transfer bar powered by a rear-mounted power take-off driven power unit. The bar produces more than 20,000 volts to kill weeds, says chief executive officer Kevin Olson.

“That voltage, when it contacts that weed, forces the weed to conduct that electricity in that current and when that happens, it forces that current through there, which generates a tremendous amount of heat, and it boils all of that water out of that stem.

“In that process, the cell walls explode and the plant loses its vitality, and it basically collapses and dies into the canopy within seconds after passing.”

The most exciting development in the LW-10, says Olson, is its flexible human machine interface (HMI), which controls voltage, current, interlocks and power supply from the tractor cab.

“I can actually use a slide rule on my finger and slide my controls up and down for increasing and decreasing the voltage and current.… There’s a lot of parameters that we can adjust.”

Lasco has also increased its generator/transformer size for reliability and heat reduction.

“Rather than running the generator at maximum capacity, I only run my generator at about 80 per cent and with my current limit, I can set that generator so it will never, ever produce more amperage than what my target amp setting is,” Olson says.

“Say my maximum output of my generator is 300 amps. I can set that at 275, 280 and keep that in a safe operating zone so I never burn up a generator.”

The generator’s output can be adjusted in the tractor cab from 60 to 600 amps using the company’s electric discharge system. This gives the operator the ability to adjust amperage to plant and canopy conditions for best results, says Olson.

Grounding coulters

Grounding coulters are essential for completing the electrical circuit and keeping the operator and those nearby safe. The coulters on the LW-10 address another challenge: ground flexibility.

“We actually have those coulters castoring now,” says Olson.

“A lot of our farmers are trying to run track tractors on our lightning weeders, and the track tractors actually pivot in the middle rather than pivot from the front to the rear axle.

“What that does is put a lot of side thrust pressure on our coulter arms and they were bending the arms. So to accommodate that, we made them castor about 20 degrees in both directions, right and left.”

Some adjustments were necessary to make the weeder more compatible with the horsepower and size of larger tractors, says Olson.

The mechanics of previous Lasco weeder models did not match these higher-powered tractors. For the LW-10, the company increased the strength of its power shaft and input pulleys, belts and sheaves.

Then there was the challenge of accommodating the crop clearance height (sometimes up to 30 inches off the ground) of modern tractors. The height of the LW-10 was increased by about five inches.

“That also gave us more crop clearance underneath the lightning weeder, and it also gave us more p.t.o. clearance for the power shaft and the drive.”

Organic appeal

Lasco’s biggest market for the weeder includes small-scale organic soybean growers in the U.S. Midwest who like the non-chemical weed control the machine enables. However, Olson says it can work in most broad acre crops, including wheat, barley and canola.

“The canola is a little tougher because … when you’re trying to control broad leaves in canola, the canola is kind of bushy and it’s tough to drive through, so you’re going to make tracks through that field if you have issues.

“But if you had a thistle problem in a canola field and you wanted to be able to take care of that, you could go out and spot control that very easily with the lightning weeder.

There are no Lasco dealerships in Canada, but Olson says he’s willing to meet customers at the border, transfer the weeder to their equipment or ship it on a truck.

“Then I go up there with a vehicle and install it on their tractor and do a tutorial with them so that they can actually learn how to run it and get the best out of the out of the machine.”