Disclosed is a mixture comprising (a) a compound of Formula I and salts thereof wherein A1, A2, A3, R1, B1, B2 and B3 are defined in the disclosure, and (b) 2-pyridinecarboxylic acid, 4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)-5-fluoro-, phenylmethyl ester (i.e. florpyrauxifen-benzyl). Also disclosed is a composition comprising the mixture. Also disclosed is a method of applying the mixture to undesired vegetation comprising contacting the undesired vegetation or its environment with an effective amount of the mixture of the invention.