Soft red winter wheat tolerance and Italian ryegrass control with AE F130060 00 plus AE F115008 00 at 12.5 plus 2.5 g ai/ha applied alone and mixed with dicamba, 2,4-D, or thifensulfuron plus tribenuron were examined in separate field experiments. AE F130060 00 plus AE F115008 00 applied alone in December injured wheat 12% or less, whereas mixtures with thifensulfuron plus tribenuron injured wheat 15% or less. AE F130060 00 plus AE F115008 00 applied alone in February or mixed with dicamba, 2,4-D, or thifensulfuron plus tribenuron injured wheat 3% or less. No treatment affected yield of weed-free wheat. AE F130060 00 plus AE F115008 00 applied in December controlled Italian ryegrass 86 to 99% in May and increased wheat yield 142 to 254%. At two of four locations, Italian ryegrass control was greater with the December application of AE F130060 00 plus AE F115008 as compared with the February application. Dicamba or 2,4-D mixed with AE F130060 00 plus AE F115008 00 reduced Italian ryegrass control in May approximately 10% in half the trials but did not affect wheat yield compared with AE F130060 00 plus AE F115008 00 applied alone. Thifensulfuron plus tribenuron mixed with AE F130060 00 plus AE F115008 00 did not affect Italian ryegrass control or wheat yield. Under greenhouse conditions, the rate of AE F130060 00 plus AE F115008 00 needed for 80% Italian ryegrass visible control and 80% shoot fresh weight reduction was increased 60 to 68% in mixtures with 2,4-D. Dicamba increased the rate needed for 80% visible control and shoot fresh weight reduction 132 to 139%.
Nomenclature: AE F115008 00 (proposed name iodosulfuron-methyl-sodium), 4-iodo-2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]benzoic acid methyl ester; AE F130060 00 (proposed name mesosulfuron-methyl), methyl 2-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]-4-[[(methylsulfonyl)amino]methyl]benzoate; Italian ryegrass, Lolium multiflorum Lam. #3 LOLMU; wheat, Triticum aestivum L. ‘Coker 9704’.
Additional index words: 2,4-D, dicamba, herbicide interactions, herbicide mixtures, LOLMU, thifensulfuron, tribenuron.
Abbreviations: I80, rate needed for 80% inhibition; NIS, nonionic surfactant; WAT, weeks after treatment.