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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Soil, Water & Air Resources Research » Research » Publications at this Location » Publication #350224

Title: Superweed Palmer amaranth is on the move: What growers should know

item Kistner-Thomas, Erica

Submitted to: American Vegetable Grower
Publication Type: Trade Journal
Publication Acceptance Date: 4/4/2018
Publication Date: 6/1/2018
Citation: Kistner-Thomas, E.J. 2018. Superweed Palmer amaranth is on the move: What growers should know. American Vegetable Grower. Available:

Interpretive Summary:

Technical Abstract: Palmer amaranth (Amaranthus palmeri) is a highly aggressive annual broadleaf weed known for its propensity for herbicide resistance. It is native to the desert regions of the southwestern United States but its range has greatly expanded over the past 50 years. To date, this weed has been detected in 28 US States, most recently in Minnesota. The competitiveness of this weed is due to its extended period of germination, rapid growth rate, prolific seed production, and ability to tolerate adverse conditions. It has developed resistance to several herbicide families (including glyphosate) making management of this weed both difficult and expensive. Palmer amaranth is a serious threat to both row and horticultural crops. This article provides a comprehensive overview of Palmer amaranth biology, impacts, identification, and management with special reference to vegetable systems. There is a significant knowledge gap in our understanding of Palmer amaranth impacts on horticultural crops. Additional research on Palmer amaranth impacts and management options in horticultural production systems is warranted. For sustainable long-term control of Palmer amaranth, a combination of preventive, cultural, mechanical, and chemical methods are strongly recommended.