Mid-Season Tough Weed: Palmer Amaranth
Caption: Palmer Amaranth
Out of a number of problematic weeds to watch for, Palmer amaranth remains a top threat across most soybean- and corn-producing regions.
Purdue University characterizes Palmer amaranth as a particularly problematic weed because of its ability to produce 100,000 to 1/2 million seeds per plant, easily disperse its seeds and compete aggressively with crops by growing 2 to 3 inches per day.
Palmer amaranth is unpredictable – it can emerge at any point in the season. Because of its erratic nature, growers should begin scouting for this weed now and continuously to do so throughout the season.
- Diamond-shaped leaves varying from green to pink
- Seed heads grow up to 30 inches long
- Could have white, V-shaped markings on the leaves
Palmer amaranth is best controlled before it reaches 4 inches in height. Because of its ability to quickly adapt and spread herbicide-resistant genes, it is essential that growers select a proven treatment containing multiple modes of action.
Syngenta recommends growers consider using herbicides, such as Acuron®, Acuron® Flexi or Halex® GT for corn. For soybeans, growers should apply Flexstar® GT 3.5 herbicide to takedown an aggressive weed like Palmer amaranth.
In preparation for scouting, take the Resistance Fighter® Weed IQ Quiz to test your weed identification knowledge.
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Photo resized. Photo credit: Joseph M. DiTomaso, University of California – Davis, Bugwood.org
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