Game changer: Palmer amaranth vs. Cornbelt farmers
Iowa State University weed specialists Bob Hartzler and Mike Owen say Palmer amaranth is just moving into Iowa, but has been confirmed in a number of counties. They stress that you need to properly identify Palmer amaranth from other varieties of amaranth. “Knowing how to differentiate the pigweeds is the key to reducing the likelihood of Palmer amaranth becoming established and spreading throughout Iowa. The easiest way to tell smooth and redroot pigweed from Palmer amaranth and waterhemp is that smooth and redroot pigweeds have hairy stems, whereas both Palmer amaranth and waterhemp have hairless stems.”
While that system may seem simple, it is not always simple. Hartzler and Meaghan Bryan offer a guide to help identify Palmer from other varieties of amaranth.
Palmer amaranth can devastate corn and soybean yields if the weed is competing with row crops. Producing hundreds of thousands of seeds per plant, and resistant to multiple herbicide modes of action, Palmer amaranth requires a strategic approach to control. That includes the way fields are cultivated, scouted, and harvested, in addition to a prescribed treatment with residual herbicides along with a post emerge application.