Glyphosate resistance has been confirmed in lamb’s-quarters in Quebec.
The finding, which comes from the CÉROM grain research centre, is the first confirmation of glyphosate resistance in the annual weed anywhere in the world. University of Guelph research scientist Dr. Peter Sikkema shared the news with those attending the Ag Business Breakfast Meeting at Ridgetown, Ont., on Tuesday.
The CÉROM reports that resistance has been found in a lamb’s-quarters population in the Montérégie region of Quebec. The resistance was detected by spraying weeds in a greenhouse under controlled conditions. It is the sixth type of weed to be identified as resistant to glyphosate in Quebec since 2017. The resistance has also been confirmed by Agriculture and Agri-Food Canada research scientist Martin Laforest.
Although he had yet to see the research report, Sikkema calls the news “fairly significant” because the CÉROM chose to make a public announcement.
Sikkema reports that he has seen some evidence of glyphosate resistance in Ontario since 2010. He notes, however, that he did not report the levels of resistance he observed because the resistance factor for the Ontario biotypes was so low that they could easily be killed and controlled the field.
Lamb’s-quarters is considered one of the most competitive annual broadleaf weeds in Ontario. According to the Ontario Ministry of Agriculture, Food and Rural Affairs’ Agronomy Guide for Field Crops, one lamb’s-quarters plant per sq. metre can cause yield losses of 12 per cent in corn and 13 per cent for soybeans.When five plants are present per sq. metre, losses can increase to 35 per cent (corn) and 38 per cent (soybeans).
“It’s not the number one weed problem — I think that’s Canada fleabane. But lamb’s-quarters is ubiquitous right across the province. So I think that’s a big deal,” says Sikkema.
