Roundup-Ready Marestail Confirmed In Eastern Montana; Can Cut Soy Yields By 87% [View all]

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Neighboring eastern Montana has its first verified case of glyphosate-resistant Conyza Canadensis, more commonly known as horseweed or marestail.

While Williams County Extension Agent Danielle Steinhoff said resistant marestail has not yet been identified in Williams County or surrounding areas that she knows of, she suggested that producers be vigilant this coming spring about reporting it if they happen to notice an instance. And though it hasn’t been verified in the North Dakota side, Glyphosate-resistant marestail was confirmed in southwest Cass County in a soybean field in 2011.

Marestail is a native plant that can sap yields in soybean and other fields by as much as 87 percent. Resistant varieties have already swept into a number of states throughout the continental United States, partly due to how easily the seeds spread. One plant can produce up to 200,000 seeds, which can be dispersed on the wind as much as 100 miles in one flight.

It is not known whether the resistant plants found in Montana adapted there or blew in from another state. However, in general, the selection and spread of herbicide resistance has occurred due to over-reliance on glyphosate and the failure to develop integrated weed management programs.

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http://www.thedickinsonpress.com/news/nation-and-world/3928245-resistant-marestail-rears-eastern-montana-fields