Notoriously hard to control “super weeds” have been found in Western Canada for the first time, agrochemical giant Monsanto has announced.
Kochia, a weed known to resist glyphosate, the key herbicide pioneered by Monsanto in their product Roundup, was found in a Southern Alberta crop in August and confirmed by Monsanto last week.
Two other resistant species have already been discovered in southwestern Ontario: giant ragweed in 2009 and Canada fleabane in 2011.
What makes the Alberta case different is that the kochia does not appear to have developed in a Roundup Ready cropping system—crops that have been genetically modified to tolerate the herbicide.
Much like antibiotic-resistant superbugs have adapted to resist medications, superweeds have become immune to glysophate due to repeated use of the herbicide without adequate incorporation of other weed management options.
The herbicide then controls all the susceptible weeds, leaving only resistant plants to reproduce.
“[Resistance] starts rare, but it will build and it will become prevalent, even predominant, across the Prairies unless we change our cultural methods,” says Glenn Tait, a Saskatchewan-based coordinator for the National Farmers Union.
Tait says dependence on Roundup has become widespread in Canada, and farmers should alternate with different methods of weed control now, before superweeds get out of control.
“If farmers jump on top of it and reduce these resistant populations right away, change their cultural methods, we should be OK,” he says.
“If we don’t pay much attention to it, in about 15 years these resistant weeds will become a very serious problem, and an extensive problem.”
A Scourge in U.S.
Roundup-resistant weeds have been a headache for farmers across the U.S. for over a decade.
The herbicide became widely adopted in the U.S. in the nineties, due to its effectiveness and its facilitation of no-till farming, reducing labour and costs related to ploughing.
But when Roundup-resistant weeds began appearing, U.S. farmers were forced to add increasingly toxic chemicals to their weed-fighting arsenal, or return to more expensive and labour-intensive techniques from decades earlier, such as hand-weeding and tillage.
Glyphosate resistance has also occurred in other parts of the world including South America, Europe, China, and Australia, according to a 2010 WeedScience.com survey.
The Alberta case is particularly significant considering Canada is the biggest exporter of spring wheat, canola, durum, and malting barley in the world, much of it produced from the Prairie provinces.
Monsanto is working with Agriculture and Agri-Food Canada and the University of Alberta to develop specific solutions to deal with glyphosate-resistant kochia.
Monsanto spokesperson Trish Jordan says the company has also increased communication with farmers, as well as education tools, to ensure best practices are employed.
“When something like this happens, it’s a good opportunity to remind [farmers] and say, ‘You always have to be cognizant of what you’re doing,'” she says.
“Glysophate resistance happens, just like resistance to other chemistries, because of the improper or inadequate use of it.”
Jordan says resistance has been relatively less common in Canada than the U.S. because conditions are more favourable for frequent crop rotation.
Some analysts claim superweeds will have a major impact on agriculture globally, affecting farm production costs, food prices, crop yields, and that the subsequent dependence on herbicides could have devastating environmental consequences.
