Combination Effects of Acifluorfen with Crop Oil Concentrates and Postemergence Grass Herbicides

Abstract

Greenhouse studies were initiated to identify potential interactions of the postemergence herbicide acifluorfen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid} with the postemergence grass herbicides sethoxydim {2-[1-(ethoxyimino) butyl]-5-[2-(ethylthio) propyl)-3-hydroxy-2-cyclohexen-1-one}, diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy]propanoic acid}, and RO-13-8895 [acetone 0-(D-(2-(p-[(α,α,α-trifluoro-p-tolyl)oxy) phenoxy)propionyl)oxime}. Greatest control of barnyardgrass [Echinochloa crus-galli(L.) Beauv. # ECHCG] was obtained with the combination of acifluorfen and sethoxydim plus a crop oil concentrate. This combination increased foliar absorption of14C-acifluorfen by barnyardgrass but not by soybean [Glycine max(L.) Merr. ‘Corsoy’]. The combination of acifluorfen with diclofop appeared to reduce phytotoxicity to barnyardgrass and increase it to soybean. Little or no interaction was observed in combinations of acifluorfen and RO-13-8895.