When glyphosate-resistant waterhemp was first found in Lambton County in 2014, College of Guelph weed scientist Peter Sikkema by no means imagined the course the weed would take across Ontario, or the pace it will journey.
In 2020, Sikkema and his workforce collected seeds in Leeds & Grenville County. “So that means glyphosate-resistant waterhemp has moved 700 kilometers in six growing seasons, which really surprises me.” The invading resistant weed, usually misidentified as redroot, inexperienced, or clean pigweed, has now been present in 14 counties across the province.
Sikkema shared these insights throughout a Ridgetown/Simcoe digital agribusiness breakfast assembly earlier this month. Much more regarding he says is the proliferation of a number of resistant waterhemp. In eight of the counties, four-way resistance has been confirmed, making the weeds proof against Group 2, 5, 9 and 14 herbicides.
The course and pace of the unfold has left Sikkema and his analysis workforce scratching their collective heads. “The rapid movement of Canada Fleabane across Ontario is quite understandable — it’s windblown seed,” he says. “But I don’t fully understand how the waterhemp seed is moving across the the province as quickly as it is.”
In soybeans, Sikkema’s analysis reveals that the typical yield affect of waterhemp is 43 per cent, however he has documented losses of as much as 93 per cent within the highest populations noticed in Ontario. Related yield losses have been noticed in corn.
One other thriller Sikkema is wrestling with is genetic variations of waterhemp discovered within the province. He notes that the profile of resistant seeds discovered in several fields in Leeds & Grenville County is kind of distinct and totally different.
“That would suggest that there are multiple different sources of waterhemp seed in the county, 700 kilometres away from where it was first identified in the province,” notes Sikkema. “Obviously it’s coming from different sources.”
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So the place are all these waterhemp biotypes coming from? That’s a loaded query that’s troublesome to reply, says Sikkema. He notes that College of Toronto analysis wanting on the biotype of waterhemp present in Essex County signifies it’s nearly an identical to waterhemp present in Mississippi.
How did it find yourself in southwestern Ontario? That too is a puzzling query, says Sikkema, noting that seed, contaminated gear, or migrating waterfowl are all attainable sources.
One other twist to this story is the profile of the waterhemp first present in Lambton County — it’s nearly genetically an identical to the waterhemp that’s been present in Ontario for the final 150 years. That makes it distinctly totally different from the resistant weeds present in close by Essex.
Sikkema can be attempting to wrap his head across the motion of native Ontario waterhemp that’s resistant in Lambton County. “Historically, that waterhemp was only found along open water courses in the province. But something has changed in the last 20 years and it’s adapted to our corn and soybean production systems and now it’s found in commercial fields.”
How can farmers sort out the yield robber? In corn, primarily based on Sikkema’s analysis, the Group 27 herbicides actually are the spine for managing a number of resistant waterhemp. Integrity (Group 14/15) has additionally supplied good management.
In soybeans, the perfect soil-applied herbicide is Fierce, says Sikkema. Nevertheless, he notes that whereas this product delivers the perfect stage of management, the margin of crop security could be fairly slim for soybeans in burdened environments. For extra on waterhemp management choices go to Area Crop Information.