A recent Ipsos-Reid survey has found that more Canadian farmers suspect they have weeds that are resistant to herbicides on their farm, and that weeds in their fields are harder to control.
This second annual opinion survey, commissioned by the Canadian arm of chemical firm BASF, found 43 per cent of farmers -- a jump of six points -- suspect they have some level of herbicide resistance in their fields.
At the same time, 63 per cent, an increase of seven points from the survey in 2012, now see the weed species in their fields as "tougher to control."
The survey was completed as a phone poll of 500 farmers from across Canada and required farmers to have a minimum acre threshold to participate in the survey.
"We need to understand our customers, and this Ipsos-Reid study has helped do this," said Joel Johnson, BASF's brand manager for western herbicides. "We're starting to see this change -- the needle is moving. Resistance is an issue and it's not going away, so it's also part of answering the question on 'Are we helping to drive this proactive approach?'"
Also telling from the survey was that fewer growers understand they're using multiple modes of action to control or manage their weed species. According to the poll results, 67 per cent of growers "strongly agreed" that the herbicides they use are formulations that are from more than one group. That's a drop of 10 percentage points.
On the other hand, the number of those who agree glyphosate on its own is ineffective in controlling weeds is up seven points, to 47 per cent.
Johnson says farmers are becoming more aware of what they're using but more needs to be done to increase the understanding of what's happening where resistance is concerned. In parts of the U.S., Palmer amaranth has reached the point where some farmers are more concerned with gaining control of the weed rather than higher soybean yields.
Glyphosate-resistant Palmer amaranth was first confirmed in Georgia in 2005 and is now found in 19 states. It entered the southern tier of Illinois and into Ohio in 2010, Michigan in 2011 and five counties in northern Indiana in October 2012.
Research by Purdue University weed specialist Bill Johnson found resistant Palmer amaranth seed to be capable of withstanding applications equivalent to seven gallons per acre of generic glyphosate. It's also a resistance issue exclusive to the U.S. -- for now.
Despite the rapid spread of Palmer amaranth, Canada fleabane is still the leader in terms of weed species in the U.S. that are resistant to various active ingredients, with 24 states confirming cases of glyphosate resistance, alone.
Waterhemp and giant ragweed are tied for third in terms of the number of states where glyphosate resistance has been found (13 states for both). But the issue with waterhemp is that it's resistant to five different groups of common herbicides, including ALS inhibitors, PPO inhibitors and triazines, and resistant to different combinations, as well.
"Some other"
The situation in Canada is not nearly as critical, and that's the way advisers and extension personnel want to keep it.
Currently, glyphosate resistance has been confirmed in Canada fleabane, giant ragweed and common ragweed in Ontario, and kochia in Western Canada.
What's troubling, BASF's Johnson said, is the perception that "some other" new herbicide will become available in time to save growers. There isn't anything new, so the time to deal with herbicide resistance is now, using available chemistries.
"In a way, it's good news that growers are thinking they do have resistance because now there's the perception of resistant weeds that's growing, so growers are paying more attention," he said.
-- Ralph Pearce is a field editor for Country Guide at St. Marys, Ont.
