Managing Herbicide Resistance with Electric Weed Control

Mar 12, 2021

By Marcelo Moretti

Herbicide resistance has also been a problem in tree nut crops for quite some time. In hazelnuts in Oregon, the most problematic herbicide-resistant weed is Italian ryegrass. Resistance is now confirmed to herbicides in groups 1, 2, 9, 10, 15, and 22. Resistance to more than one mode-of-action is often found in the populations. Non-chemical alternatives are needed. We recently started a project to evaluate electric weed control (EWC) funded by USDA – Crop Protection and Pest Management program.

Electric weed control (EWC) has been investigated for almost 40 years. However, it remains an emerging technology in the USA and elsewhere in the world. A few companies, mostly in Europe and Latin America, offer commercial EWC units. In Oregon, we initiated our work on EWC only this morning! Assembly details and small changes required a couple of weeks to resolve, but now we are ready to start EWC trials in Oregon for 2021. We are collaborating with Zasso (Indaiatuba, Brazil), working with an EH30 Thor unit (Figure 1).

Figure 1. Electric weed control unit manufacturer by Zasso operating at Lewis Brown Research Center in Corvallis, OR. The electricity is applied through the metal probes. The electric resistance heats up the plant, producing steam.

Figure 2. Common groundsel moments after treatment with EWC (left) and non-treated (right).

How it works

The system generates a high voltage current that is applied directly to the plant via foliage contact with a metal bar. The voltage is conducted through the plant towards the roots. As high voltage passes through the plant, electrical resistance generates heat, leading to cell membrane rupture and plant death. Watch a short YouTube video of the process.

Power requirement

A PTO-driven generator produces electricity. A transformer increases the generator's voltage to 5,000-12,000 V. Tractor horsepower, and EWC unit configuration controls the voltage. The unit requires at least 75 hp power at the PTO, but I am inclined to say that you may want a bit more in wet soils with high clay content soil.

Figure 3. Area treated with Electric Weed Control.

Acknowledgments

The USDA Crop Protection and Pest Management Program funds this work (award no. 2020-70006-32982). I would also like to acknowledge the Oregon Hazelnut Commission's support and the local growers who will participate in this project.

Source : ucanr.edu

Video: From Students to Solutions | On The Brink: Season 2, Episode 14

Ask Canada’s most decorated soybean breeder his favourite part of the job and he doesn’t name a single variety. He names the students.

Istvan Rajcan is a professor of soybean breeding and genetics in the Department of Plant Agriculture at the University of Guelph, where he has run the soybean breeding program for 28 and a half years. In that time he has developed 87 soybean cultivars, published 140 refereed papers and trained 51 graduate students. In 2025 he received the Public Sector Impact Award from the National Association for Plant Breeding.

He is also worried. In this episode he says Canada is at a crossroads, pointing to recent government cuts to plant breeding programs and to the facilities that support them. His prescription is structural. "Plant breeding funding formula has to be a long-term one," he says.

The formula he is defending is the public-private matching arrangement his program runs on. Private seed companies fund the work, provincial or federal money matches it, and the combined pool stretches each dollar further than either source could alone. At the National Association for Plant Breeding annual meeting in June, he says American public breeders were often surprised at how well that collaboration works in Canada.

He also describes how the people entering plant breeding have changed. His early graduate students came mostly from farms. More recently they include, in his words, "city kids who just became excited about genetics."

Topics covered:

Why public-private plant breeding funding in Canada needs a long-term

commitment rather than a larger one

How matching private seed company investment with provincial and federal

dollars multiplies research capacity

How the graduate student pipeline into plant breeding has shifted from

farm kids to city kids