The invention provides insecticidal compositions exhibiting excellent knockdown activity against public health pests, in particular cockroach species, comprising compounds of formula (I): ##STR1## wherein X represents a group of formula: ##STR2## where (i) R.sup.1 and R.sup.2 are each selected from hydrogen, halo and C.sub.1-4 alkyl, or (ii) R.sup.1 is hydrogen and R.sup.2 represents either R.sup.3 (R.sup.4)C.dbd.CH-- or R.sup.3 (R.sup.4)(R.sup.5)C--CH(R.sup.5)--, where R.sup.3 and R.sup.4 are selected from hydrogen, methyl, halo and C.sub.1-2 haloalkyl and R.sup.5 is selected from chloro and bromo. The invention also provides methods of use of the compositions, novel compounds of formula (I) and processes for their preparation.