Research Finds Multiple Herbicide-Resistant Marestail is Present in New York

Joshua Putman, Field Crops and Forage Specialist
Southwest New York Dairy, Livestock and Field Crops Program

April 1, 2021
Research Finds Multiple Herbicide-Resistant Marestail is Present in New York

Thirty populations of marestail (horseweed) were collected in the fall of 2020 and are being screened for resistance to commonly used herbicides. Of the 30 collected, 27 appear to be resistant to glyphosate (Roundup) and 28 populations appear to be resistant to cloransulam herbicide, an ALS-inhibitor. This indicates that we have multiple-resistance in NY. It is also suspected that 4 of these 30 samples may be resistant to paraquat (Gramoxone) herbicide. The screening efforts will continue to evaluate the effect of products like 2,4-D and dicamba, Liberty, and PPO-inhibiting herbicides like Reflex and Sharpen.




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Join Joshua Greene, Director of Education at Trees For Graziers, Jonathan Bates, Statewide Agroforestry Educator, and Lynn Bliven, owner of Wild Geese Farm for a full day training event that will include classroom and hands-on sessions. The focus will be on DIY silvopasture projects on small grazing farms. We will address the practical considerations of tree establishment, protection, and maintenance while learning how silvopasture can help address your farm's resource concerns and enhance livestock grazing.

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