Scientists from the University of Guelph have discovered more soybean fields in southwestern Ontario where weeds have developed resistance to glyphosate.
Monsanto Canada confirmed in a news release Nov. 15 that researchers have detected glyphosate resistant giant ragweed in 16 fields in Essex County near Windsor, Ont.
In late March, Monsanto announced the first confirmed case of a glyphosate resistant weed in Canada.
The giant ragweed had been found in a soybean field close to Windsor.
Monsanto and U of G researchers then tested giant ragweed plants in Essex, Kent and Lambton counties.
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The results confirm that glyphosate resistance is not an isolated incident in southwestern Ontario.
“We have been able to demonstrate that plants from the populations of giant ragweed we collected in 16 of the 57 fields survived when they were sprayed with glyphosate in the greenhouse,” said Francois Tardif, a U of G plant scientist who is part of the research team studying Roundup resistance in Ontario.
Mark Lawton, Monsanto Canada’s technology development lead in Eastern Canada, said the company wants to provide producers with as much information as possible.
“(We’re) trying to be true to the commitment for communication and transparency,” he said.
“In general, giant ragweed is just present in that southwestern Ontario area…. It doesn’t mean that we might not find it in other counties if you were to look more. But we do know, in Essex, it’s a heavy soybean cropped area and more likely to grow soybeans continuously.”
Lawton said researchers are also developing crop management practices for producers affected by Roundup resistance.
Field research conducted this year showed that two products were most effective in controlling glyphosate resistant ragweed on soybean fields, he added.
“Eragon, which is a new chemistry from BASF, and FirstRate, those were the best of the bunch.”
