Experiments were conducted in the 2000 to 2001 and 2001 to 2002 growing seasons to evaluate the efficacy of AE F130060 03 plus AE F107892 with nonionic surfactant (NIS) or methylated seed oil (MSO) plus urea ammonium nitrate (UAN) applied in November (early postemergence, EP), January (middle postemergence, MP), and March (late postemergence, LP) for control of Italian ryegrass in barley. AE F130060 03 plus AE F107892 was also combined with MSO and UAN and various postemergence (POST) small grain herbicides at the three application timings. All AE F130060 03 plus AE F107892 treatment combinations controlled Italian ryegrass at least 84% at the three application timings. Treatment combinations of AE F130060 03 plus AE F107892 applied LP generally resulted in lower yields because of increased duration of Italian ryegrass competition, increased barley injury, and insufficient time for barley to recover from the injury. Transient phytotoxicity to barley occurred after EP and MP applications of all AE F130060 03 plus AE F107892 treatment combinations. LP applications of MSO and UAN or other POST small grain herbicides combined with MSO and UAN increased barley injury compared with injury from AE F130060 03 plus AE F107892 applied with NIS. Results indicate that AE F130060 03 plus AE F107892 treatments are an effective method for control of Italian ryegrass in barley; however, treatments should be applied either EP or MP to reduce early Italian ryegrass competition and allow sufficient time for barley recovery from injury before harvest.
Nomenclature: AE F107892, [diethyl 1-(2,4-dichlorophenyl)-5-methyl-2-pyrazoline-3, 5-dicarboxylate]; AE F115008 00, [methyl 4-iodo-2-[3-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-ureidosulfonyl]benzoate, sodium salt]; AE F130060 00, [methyl-2-[3-(4,6-dimethoxypyrimidin-2-yl)ureidosulfonyl]-4-methane-sulfonamidomethylbenzoate]; AE F130060 03 is a mixture of AE F130060 00 and AE F 115008 00; Italian ryegrass, Lolium multiflorum (Lam.) #3 LOLMU; barley, Hordeum vulgare (L.) # HORVX, ‘Nomini’.
Additional index words: Bromoxynil, chlorsulfuron, crop tolerance, dicamba, diclofop, diclofop resistance, metsulfuron, thifensulfuron, tribenuron, Triticum aestivum, TRZAW.
Abbreviations: EP, early postemergence; LP, late postemergence; MP, middle postemergence; MSO, methylated seed oil; NIS, nonionic surfactant; POST, postemergence; UAN, urea ammonium nitrate; WAT, weeks after treatment.