Response of Certain Crops to Glyphosate in Irrigation Water

Abstract

Six crop species were irrigated with water that contained up to several times more glyphosate [N-(phosphonomethyl)glycine] than would be expected in irrigation water as a result of spraying ditchbank vegetation. In June or July 1976, sugarbeets (Beta vulgarisL.), alfalfa (Medicago sativaL., ‘Vernal’), grain sorghum [Sorghumbicolor (L.) Moench], field beans (Phaseolus vulgarisL., ‘Pinto’), tomatoes (Lycopersicon esculentumMill., ‘Roza’), and squash [Cucurbita moschata(Duch.) Duch. ex Poir.] were sprinkler-irrigated with water that contained glyphosate at 0, 0.02, 0.22, or 2.2 ppmw. These concentrations were applied continuously for 8 h to make total applications of 0, 0.01, 0.1, and 1.1 kg/ha, respectively. No injury symptoms developed in any of the crop plants. Yields of treated crops were equal to those produced by untreated plants.