The present invention relates to a method of selectively controlling weeds at a locus comprising crop plants and weeds, wherein the method comprises application to the locus of a weed controlling amount of an aqueous spray composition comprising a compound of formula (I) wherein R1 is selected from the group consisting of C1-C6alkyl, C2-C6alkenyl, C2-C6haloalkenyl, C2-C6alkynyl, C2-C6haloalkynyl, C3-C6cycloalkyl, C1-C6haloalkyl, C1-C4alkoxy-C1-C4alkyl and C1-C4alkoxy- C1-C4alkoxy-C1-C4alkyl; and R2 is C1-C6haloalkyl; or an agriculturally acceptable salt therefore; wherein in the pH of the spray composition is from about 5 to about 9. The invention further relates to a liquid substantially non-aqueous herbicide composition comprising a compound of formula (I) as defined above and a pH adjuster, and to the use of a pH adjuster to reduce the phytotoxicity of a compound of formula (I) in crop plants.