Compositions and methods for controlling herbicide resistant weeds

A composition comprising (i) a herbicide; and (ii) a compound of formula I, wherein R1 is a C1 to C12 alkyl; and R2 is selected from H and a C1 to C5 alkyl. In one embodiment, and with reference to the compound of Formula I, R1 is a propyl group and R2 is a methyl group. Suitably, the herbicide is a phenoxy herbicide, such as diclofop, or a derivative thereof. The composition can comprise a rapid release formulation of the compound of formula I, and a non-rapid release formulation of the herbicide. The use of a compound of formula I as a herbicide synergist is also claimed. A method of controlling weeds is also claimed, the method comprises contacting the weeds with (i) a compound of formula I and (ii) a herbicide. In one embodiment, the weeds are contacted with a compound of formula I before being contacted with the herbicide. Formula I