Number up from 2009 survey | A recent survey showed 31 percent of fields had resistant weeds
According to growers, herbicide-resistant weeds are affecting the bottom lines of producers across the country.
In a recently released poll, commissioned by BASF Canada, 75 percent of Canadian producers said that herbicide-resistant weeds are having either a small to large impact on their earnings.
The results didn’t surprise BASF’s Michael Schaad, the company’s business manager, Eastern Canada crop protection.
The numbers on how many farmers said they have herbicide-resistant weeds on their land — 37 percent across the country — were more surprising, he said.
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“I would say that they know that a lot of growers are thinking about it and if they’re not thinking about it, maybe they should be,” he said.
Schaad explained that 55 percent of respondents in Manitoba, where producers have battled Group 1 resistant wild oats, said they have herbicide-resistant weeds. That’s above Alberta’s total of 43 percent.
The first case of glyphosate-resistant kochia was confirmed in the southern portion of that province earlier this year.
Schaad said 26 percent of Saskatchewan producers said they have herbicide-resistant weeds on their farmland.
Recently released data from Agriculture Canada found that 31 percent of surveyed fields had herbicide-resistant weeds. The numbers come from a 2009 field survey and were up from 10 percent in 2003, showing increases in Group 1 resistant wild oats and green foxtail and Group 2 resistant cleavers.
The most recent data for Alberta, using survey information from 2007, and Manitoba, surveyed in 2008, found a presence of 27 percent and 58 percent, respectively.
Previous surveys have already shown that 90 percent of the kochia population is herbicide resistant and cases of Group 2 resistant nightshade, ragweed and pigweed have been confirmed in Quebec.
“There’s maybe some complacency in that growers think there’ll be something new coming along to solve the problems and that’s not necessarily the case,” said Eric Johnson, a weed biologist with Ag Canada. “If there was, it’d probably be here by now.”
BASF’s poll found that half of farmers say weeds are getting tougher to control, while most say that they’re using herbicides from more than one group to manage weeds.
A number of best management practices are recommended to slow the spread of herbicide resistance, including crop and herbicide rotations and application of herbicides with multiple modes of action.
“There’s still a tendency for growers to do what they’ve done in the past if something is successful and continue to do it until it fails,” said Johnson. “That’s probably the biggest management mistake.”
Johnson said producers have been successful controlling broadleaf weeds by tank mixing herbicides. Over the winter, producers began to hear about tank mixing glyphosate with another herbicide and altering their burndown practices.
“If they haven’t done anything in terms of tank mixing their glyphosate, they have put some selection pressure out there,” said Johnson. “So it’s pretty important that they do something in future years.”
Ipsos Reid interviewed 500 farmers across Canada March 5-12, 2012, for BASF’s poll. It has an estimated margin of error of plus or minus 4.3 percentage points, 19 times out of 20.
