Glyphosate is a broad-spectrum, post-emergence herbicide.1 It inhibits the activity of 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPS; IC50 = 5-7 ?M in a cell-free A. aerogenes extract), an enzyme in the shikimate pathway that catalyzes the conversion of shikimic acid to anthranilic acid.2,3 Foliar application of glyphosate induces foliage and rhizome necrosis of johnsongrass (S. halepense) when applied at concentrations ranging from 0.56 to 2.24 kg/hectare.4 It has been found in soil, surface water, and groundwater samples.3 Formulations containing glyphosate have been used for weed control in agriculture and horticulture.
1.Araújo, A.S.F., Monteiro, R.T.R., and Abarkeli, R.B.Effect of glyphosate on the microbial activity of two Brazilian soilsChemosphere52(5)799-804(2003) 2.Steinrücken, H.C., and Amrhein, N.The herbicide glyphosate is a potent inhibitor of 5-enolpyruvyl-shikimic acid-3-phosphate synthaseBiochem. Biophys. Res. Commun.94(4)1207-1212(1980) 3.Kanissery, R., Geirhe, B., Kadyampakeni, D., et al.Glyphosate: Its environmental persistence and impact on crop health and nutritionPlants (Basel)8(11)499(2019) 4.Parochetti, J.V., Wilson, H.P., and Burt, G.W.Activity of glyphosate on johnsongrassWeed Sci.23(5)395-400(1975)