Phenyl or bicyclo-alkenylfluoro amide pesticides

A compound of the formula (I):

• Q.sup.1 Q(CR.sup.2 .dbd.CR.sup.3).sub.a (CR.sup.4 .dbd.CF)(CR.sup.5 .dbd.CR.sup.6).sub.b C(.dbd.O)NHR--.sup.1 (I)
• or a salt thereof, wherein Q.sup.1 is a phenyl ring or a fused bicyclic ring system containing 9 of 10 ring carbon atoms, at least one ring being aromatic, or a phenyl ring or fused bicyclic ring system containing 9 or 10 ring carbon atoms substituted with halo, cyano, C.sub.1-6 alkyl and C.sub.1-6 alkoxy each optionally substituted by one or more halogen atoms or the substituent is a group S(O).sub.m.sup.R.sup.9 wherein m is 0, 1 of 2 and R.sup.9 is C.sub.1-6 alkyl optionally substituted by halo, or Q.sup.1 is a diahalovinyl group;
• Q is an alkyl chain containing 1 to 12 carbon atoms and optionally containing one or two oxygen atoms and/or an unsaturated group --CR.sup.7 .dbd.CR.sup.8 --, or --.tbd.C--, wherein R.sup.7 and R.sup.8 are selected from hydrogen or halo;
• a is 0 or 1, b is 0 or 1;
• the sum of a and b is 0 or 1;
• R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are the same or different, and are independently selected from hydrogen, halo and C.sub.1 -C.sub.4 alkyl;
• and R.sup.1 is selected from hydrogen and C.sub.1-6 hydrocarbyl optionally substituted by dioxalanyl, halo, cyano, trifluoromethyl, trifluoromethylthio or C.sub.1-6 alkoxy.