A method of combating bugs comprising contacting the bugs or their food supply, habitat, breeding grounds or their locus with a pesticidally effective amount of a compound of the formula (I) wherein W is Cl or CF.sub.3; X and Y are each independently Cl or Br; R.sup.1 is alkyl, alkenyl, alkynyl, or cycloalkyl optionally substituted with 1 to 3 halogens, or alkyl which is substituted by alkoxy; R.sup.2 and R.sup.3 are alkyl or may be taken together to form cycloalkyl optionally substituted by 1 to 3 halogens; R.sup.4 is H or C.sub.1-C.sub.6-alkyl, or the enantiomers or salts thereof. ##STR00001##