Written by: Erin Hill
Primary Source: MSU Weeds.com Blog
Horseweed/marestail has been the #1 weed submitted to MSU Diagnostic Services for herbicide-resistance screening. In 2015, all samples screened were found to be resistant to glyphosate. In 2016, screens have only been completed for 6 of the 36 samples submitted, but all thus far were resistant to both glyphosate and the ALS inhibiting herbicides (e.g. FirstRate, Group 2). With wind dispersal making this problematic weed more and more widespread with each passing year it is important to be diligent about control. Just this past month Christy Sprague has published a new MSU Weed Science bulletin addressing this issue titled, “Herbicide-resistant horseweed (marestail) in Michigan: Keys to management in no-till soybean.” Check out the bulletin to see her latest recommendations.