An insecticidal composition is provided, the composition comprising an insecticidally effective amount of one or more phenylpyrazole compounds having the general formula (I) (see claim 1) and at least one nitrogen-based fertilizer. The insecticide may be fipronil, flufiprole, ethiprole, acetoprole, pyraclofos, pyrafluprole, pyriprole, pyrolan or vaniliprole. The preferred insecticide is fipronil. The nitrogen-based fertilizer acts as a safener for the insecticide and reduces the phytotoxic effects of the compound of general formula (l) on the target plants. There is further provided a method of treating plants at a locus comprising applying to the locus a compound of the general formula (I) and a nitrogen-based fertilizer.