Now is a great time to scout for Palmer amaranth (Amaranthus palmeri) in Iowa crop fields. As of late 2018, this species had been identified in over half of Iowa’s 99 counties. While new identifications have waned since the widespread introductions in 2016, Palmer amaranth is a species to watch out for in virtually any Iowa crop field.
As of February 2017, Palmer amaranth (Amaranthus palmeri) had been found in 49 of Iowa’s 99 counties. A native of the American southwest, Palmer amaranth is more competitive than common waterhemp (Amaranthus tuberculatus), a pigweed native to Iowa. These two species are two of the most troublesome for corn and soybean farmers. Both species are known for fast development of herbicide resistance, incredible seed production on female plants (>500,000 seeds possible), and prolonged emergence.
Most people are aware of the multiple findings of Palmer amaranth across Iowa this month. Palmer amaranth has been identified both in crop fields and in conservation plantings using native seed mixes. Early detection is essential in order to prevent the new weed from getting permanently established in fields where it has been introduced.
After a busy week at a meeting in Michigan, Virgil Schmitt and I visited the Muscatine County farmer with Palmer amaranth to assess the population.
By Meaghan Anderson, ISU Extension Field Agronomist, East Central Iowa
Palmer amaranth’s presence in the state is currently confirmed in five counties. Keep an eye out this summer for this weed with Iowa State’s identification resources.
