Laboratory experiments were conducted to evaluate absorption, translocation, and metabolism of AE F130060 03 in wheat, barley, and Italian ryegrass. An additional objective was to evaluate how combinations of AE F130060 03 with dicamba affect absorption, translocation, and metabolism in wheat, barley, and Italian ryegrass. Experiments were conducted in a completely randomized design, and data were subjected to a factorial analysis. The factors included for analysis were plant type, time, and presence or absence of dicamba. Italian ryegrass absorbed 2.5, 2.0, and 1.5 times the amount of applied radioactivity 24, 48, and 96 h after treatment (HAT), respectively, compared with wheat or barley. Translocation of radiolabeled AE F130060 03 from the treated leaf blade was low and did not differ among wheat, barley, or Italian ryegrass. The rates of AE F130060 03 metabolism by the two cereal crops and Italian ryegrass were different. Ninety-six HAT, the total absorbed radioactivity metabolized by wheat, barley, and Italian ryegrass was 67, 51, and 34%, respectively. Conversely, 96 HAT, the levels of nonmetabolized AE F130060 03 were highest in Italian ryegrass, intermediate in barley, and lowest in wheat. The lower absorption of herbicide and a more rapid rate of metabolism by wheat and barley in comparison with Italian ryegrass most likely account for differential selectivity among the three plant species. Dicamba did not influence translocation or metabolism in wheat, barley, or Italian ryegrass.
Nomenclature: Dicamba; diclofop-methyl; AE F115008 00 (methyl 4-iodo-2-[3-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-ureidosulfonyl]benzoate, sodium salt); AE F107892 (diethyl 1-(2,4-dichlorophenyl)-5-methyl-2-pyrazoline-3, 5-dicarboxylate); AE F130060 00 (methyl-2-[3-(4,6-dimethoxypyrimidin-2-yl)ureidosulfonyl]-4-methane-sulfonamidomethylbenzoate); Italian ryegrass, Lolium multiflorum Lam. LOLMU; barley, Hordeum vulgare L. ‘Nomini’; wheat, Triticum aestivum L. ‘Jackson’.