Editorial: the ‘wicked problem’ of herbicide-resistant weeds

It's not only a problem of chemistry, but human behaviour itself

When I first tuned into a recent summit on herbicide resistance being broadcast live by webinar from Washington, D.C., my first thought was that I had virtually stumbled into the wrong conference.

The keynote speaker wasn’t a weed scientist. He is a sociologist. But as I listened, it became clear this speaker, and the ones who followed, were discussing the problem of herbicide-resistant weeds, and with urgency.

So who organized this event — the anti-pesticide lobby, perhaps?

Nope. It was sponsored by the Weed Science Society of America and hosted by the National Research Council. And the speakers lined up by the summit’s organizers made a compelling case that something has to change — and fast — about how weeds are managed in modern farming systems.

“Do you know what the definition of insanity is?” asked David Shaw, PhD, a past president of WSSA and chair of the WSSA Herbicide Resistance Education Committee. “It’s continuing to do what we have been doing expecting different results.”

It pretty much sums up where the industry is at with the lengthening list of herbicide-resistant weeds. As the speakers at this event pointed out, the discussion over herbicide-resistance management needs to move beyond raising awareness and telling farmers what to do about it.

Farmers are aware. The management tools and options are well documented. The lastest BASF poll of Canadian farmers says 94 per cent of Manitoba farmers are worried about it, nearly 60 per cent think they already have resistance on their farms, and their hunch is supported by the data.

But when it comes to controlling weeds, they, like farmers across North America, continue to rely almost solely on chemical weed control.

Some characterize this as a biological problem. Farmers’ dependence on chemistry creates selection pressure that causes weeds to evolve resistance.

Others will say it is a technological problem, focusing on the need for different combinations and new active ingredients to preserve or replace wonder herbicides such as glyphosate.

But Shaw said it goes much deeper than that. “Fundamentally, at its core, it is a problem of human behaviour — it’s the choices you and I have been making,” he said.

Hence the enlistment of sociologists to help explore and explain why farmers, with full support of the pest-control industry, continue to make decisions today that threaten their future ability to farm.

An overexaggeration, you say? Stephen Powles, an Australian weed scientist considered one of the world’s leading experts in herbicide resistance, even calls it a threat to global food security because it predominantly affects the world’s top grain exporters.

These production powerhouses are characterized by big farms, a high reliance on herbicides, low biodiversity and a farming culture fixated on the next technological solution. He compares farmers’ chemical addiction to an illness — HOS (herbicide-only syndrome.)

In other words, that’s the problem. The herbicide-resistant weeds are only a symptom.

Powles said the surge in multiple-resistant weeds, some of which are resistant to chemistry that isn’t even in use yet, is a strong indicator that herbicides alone are not sustainable.

In sociological terms, HOS is considered a “wicked problem,” meaning it involves “multiple, complex and uncertain causes and effects over time in the way humans and nature interact,” said Raymond Jussaume, head of sociology at Michigan State University.

Farmers’ management decisions are driven by multiple factors, including financial, but also time management, the surge in rented land, and farming culture. As such, Jussaume said it defies simple technological fixes such as stacked traits, and requires adaption to a more holistic approach to weed management by the whole community.

One potentially powerful motivator for change is the looming reality that farmers may have to return to tillage, a prospect many find abhorrent. Another, is the possibility that governments will look to regulation if the farm community doesn’t come up with a plan on its own.

Last week a British weed specialist brought a chilling message to farmer meetings in Manitoba and Saskatchewan about the difficulty and cost of controlling herbicide-resistant black-grass in Europe. In the U.S., some farms are now being lost because of the difficulty of controlling glyphosate-resistant Palmer amaranth.

Herbicide manufacturers and distributors are already well aware of the threat, which ultimately means no market for their product. The message to rotate herbicides to prevent resistance is well taken, but to keep them in the tool box, it may also mean using them less often.

Don’t take my word for it. On the next rainy day, tune in for yourself by visiting the Weed Science Society of America website.

About the author

Vice-President of Content

Laura Rance

Laura Rance is vice-president of content for Glacier FarmMedia. She can be reached at [email protected]

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