Abstract: Field research was conducted to determine effects of application rate, spray adjuvants, and spray carriers on visible control of downy brome, jointed goatgrass, and cheat and potential injury to wheat by MON 37500. MON 37500 at 24 and 46 g/ha with and without a methylated seed oil or nonionic surfactant and carriers of water, urea ammonium nitrate (UAN), and a 1:1 water/UAN combination were applied to the weeds at the one- to four-leaf stage. Cheat was the most susceptible weed to MON 37500, with control consistently above 87% with all treatments except MON 37500 at 24 g/ha in water 26 weeks after treatment. Downy brome control was more variable, with ratings ranging from 50 to 99% among treatments. For jointed goatgrass, only moderate stunting was observed from all MON 37500 applications. Both wheat varieties showed early season injury after MON 37500 was applied with UAN and either adjuvant; however, no visible injury or yield reduction to either wheat variety was noticed at harvest.
Nomenclature: MON 37500, 1-(2-ethylsulfonylimidazo[1,2-a]pyridin-3-ylsulfonyl)-3-(4,6-dimethoxypyrimidin-2-yl)urea; UAN, urea ammonium nitrate–28% N; jointed goatgrass, Aegilops cylindrica Host. #3 AEGCY; cheat, Bromus secalinus L. # BROSE; downy brome, Bromus tectorum L. # BROTE; hard-red winter wheat, Triticum aestivum L.; Jagger; ‘2137’.
Abbreviations: WAT, weeks after treatment.