Weed Management

Palmer amaranth, Amaranthus palmeri, is a new invasive weed in the pigweed family that has become a major challenge for farmers across the U.S. for much of the last decade. Native to the Sonora Desert of Arizona and Northern Mexico, Palmer amaranth is well adapted to the hot Maryland summers. It was first discovered in Maryland during the mid-twentieth century, but the presence of herbicide resistant Palmer amaranth was not confirmed until 2014. Since then it has spread to most regions of the state including Eastern, Southern, and Western Maryland. The spread of Palmer amaranth has been hastened by the movement of contaminated equipment, feed, and seed from infested areas.

Authors: Matt Morris
Ben Beale

Yellow, green, and giant foxtail are the three most common weedy foxtail species in Maryland. Knowing the differences between foxtail species and look-alike grassy weeds can assist with identification, and the selection of effective weed management strategies. Title: Know Your Foxtails (FS-2023-0658); Authors: Dwayne D. Joseph, and Leo Kerner

Authors: Dwayne Joseph
Leo Kerner

Pigweeds are annual weeds that can cause significant problems for Maryland farmers. Palmer amaranth and waterhemp are two pigweeds that are especially troublesome, and have been designated as noxious weeds by the Maryland Department of Agriculture. Therefore, it is required that these two species be actively managed to prevent their spread and resulting negative impacts on Maryland agriculture. To the untrained eye, Palmer amaranth and waterhemp can appear similar to each other and to other pigweed species. However they can be easily distinguished from one another by looking at some key botanical characteristics. Becoming familiar with these species allows for earlier detection, and as a result, improved management practices. Authors: Kurt Vollmer, Ph.D., and Ben Beale; Title: Keys to Identifying Palmer Amaranth and Waterhemp (FS-2023-0653)

Authors: Kurt Vollmer
Ben Beale