Palmer amaranth was at a new site in Benson county late last week. Palmer was first detected at a different site in Benson county in 2018. At this time, we do not believe these two infestations are related. The new infestation was found along some sloughs and creeping into a soybean and wheat field. The plants are being handweeded out of crop fields and mowed in the sloughs. Ongoing investigations will try to determine the source of the infestations, but custom combines are currently thought to be the source of the infestation.

This serves as a good reminder that this is the time of year to be vigilant and look for Palmer amaranth in and around fields. Plants will be setting seed as we get closer to the end of summer, and preventing seed production and seed rain in 2020 are some of the best tools we have to manage infestations beyond this year. If you find plants that you suspect are Palmer amaranth, please contact your County Agent, local Area Extension Agronomist, Brian Jenks, or myself. Early detection will remain our best management tactic to prevent this weed from gaining a foothold in North Dakota.

Joe Ikley

Extension Weed Specialist