EPSPS Inhibitor (HG 9) Herbicide Injury in Soybean
Published: 09/08/2023
EPSPS inhibiting, or Group 9 herbicides, bind to the enolpyruvyl shikimate phosphate synthase (EPSPS) enzyme, blocking the synthesis of amino acids needed for photosynthesis.
EPSPS inhibitor herbicides should only be applied to soybean cultivars resistant to glyphosate. Injury may be caused by physical drift, tank contamination, or misapplication to non-resistant soybean varieties. Injury can appear in 7-10 days and can take as long as two weeks after exposure to appear depending on the rate of exposure. Symptoms appear in the newest growth of soybean first, particularly the meristem, and appear as plant wilting, chlorosis, and eventual necrosis. Early symptoms may mimic nutrient deficiencies.
Glyphosate injury to soybeans.
Cal Shumway, Bob Scott, and John Boyd, www.uada.edu
See the Herbicide Classification Chart from Take Action for herbicide selection information to help slow the development of resistant weeds.
Prepared and reviewed by Dr. Thomas (Tommy) Butts, University of Arkansas; Dr. Joe Ikley, North Dakota State University; the Integrated Pest Management Program at Iowa State University; Dr. Sarah Lancaster, Kansas State University; Dr. Travis Legleiter, University of Kentucky; and Dr. Rodrigo Werle, University of Wisconsin-Madison.
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