A compound of the formula I wherein A represents N; R 1 represents C 1 -C 2 alkyl, C 1 -C 2 haloalkyl, C 2 -C 3 alkenyl or C 2 -C 3 haloalkenyl. R 2 represents cyclopropyl, C 1 -C 6 haloalkyl, C 2 -C 6 alkenyl, C 2 -C 6 haloalkenyl or wherein W 1 represents H or halogen; X 1 represents H, halogen, nitro, cyano, formyl, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 1 -C 6 alkoxy, C 2 -C 4 alkoxyalkyl, C 2 -C 6 alkylcarbonyl, C 1 -C 6 alkythio, C 1 -C 6 alkylsulfinyl, C 1 -C 6 alkylsulfonyl, C 2 -C 4 alkenyloxy, C 2 -C 4 alkynloxy, C 2 -C 4 alkenylthio, C 2 -C 4 alkynylthio, C 1 -C 6 haloalkyl, C 2 -C 6 halo-alkenyl, C 2 -C 6 haloalkynyl, C 1 -C 6 haloalkoxy, C 2 -C 4 haloalkoxyalkyl, C 2 -C 6 haloalkylcarbonyl, C 1 -C 6 haloalkylthio, C 1 -C 6 haloalkylsulfinyl, C 1 -C 6 halo-alkylsulfonyl, C 3 -C 6 trialkylsilyl, C 2 -C 4 haloalkenyloxy, C 2 -C 4 haloalkynyloxy, C 2 -C 4 haloalkenylthio, C 2 -C 4 haloalkynylthio, -C OR 7, -C NR 6 R 7, -CR 6 NOR 7, -NR 6 R 7, -NR 6 OR 7, -NR 6 SO 2 R 7, -NR 6 C R 7, -NR 6 C OR 7, -NR 6 C NR 6 R 7 or -NCR 6 NR 6 R 7; Y 1 represents H, halogen, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, C 1 -C 6 haloalkoxy, C 2 -C 6 alkenyl or C 2 -C 6 haloalkenyl, or, when X 1 and Y 1 are taken together, represents -O(CH 2) n CH 2 -, or -O(CH 2) n O- wherein n = 1 or 2; and Z 1 represents H or halogen; R 3 and R 4 independently represent H, C 1 -C 6 alkyl, C 3 -C 6 alkenyl, C 3 -C 6 alkynyl, hydroxy, C 1 -C 6 alkoxy, amino, C 1 -C 6 acyl, C 1 -C 6 carboalkoxy, C 1 -C 6 alkylcarbamyl, C 1 -C 6 alkylsulfonyl, C 1 -C 6 trialkylsilyl or C 1 -C 6 dialkyl phosphonyl or R 3 and R 4 taken together with N represent a 5- or 6-membered saturated ring; and R 6 represents H, C 1 -C 4 alkyl or C 1 -C 4 haloalkyl; and R 7 represents C 1 -C 4 alkyl or C 1 -C 4 haloalkyl; and agriculturally acceptable derivatives of the carboxylic acid group, wherein said agriculturally acceptable derivatives of the carboxylic acid group are agriculturally acceptable salts, esters and amides, and wherein "alkyl", "alkenyl", "alkynyl" and "alkoxy" in each case designates a straight chain, branched chain or cyclic moiety. A represents N; R 1 represents C 1 -C 2 alkyl, C 1 -C 2 haloalkyl, C 2 -C 3 alkenyl or C 2 -C 3 haloalkenyl. R 2 represents cyclopropyl, C 1 -C 6 haloalkyl, C 2 -C 6 alkenyl, C 2 -C 6 haloalkenyl or W 1 represents H or halogen; X 1 represents H, halogen, nitro, cyano, formyl, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 1 -C 6 alkoxy, C 2 -C 4 alkoxyalkyl, C 2 -C 6 alkylcarbonyl, C 1 -C 6 alkythio, C 1 -C 6 alkylsulfinyl, C 1 -C 6 alkylsulfonyl, C 2 -C 4 alkenyloxy, C 2 -C 4 alkynloxy, C 2 -C 4 alkenylthio, C 2 -C 4 alkynylthio, C 1 -C 6 haloalkyl, C 2 -C 6 halo-alkenyl, C 2 -C 6 haloalkynyl, C 1 -C 6 haloalkoxy, C 2 -C 4 haloalkoxyalkyl, C 2 -C 6 haloalkylcarbonyl, C 1 -C 6 haloalkylthio, C 1 -C 6 haloalkylsulfinyl, C 1 -C 6 halo-alkylsulfonyl, C 3 -C 6 trialkylsilyl, C 2 -C 4 haloalkenyloxy, C 2 -C 4 haloalkynyloxy, C 2 -C 4 haloalkenylthio, C 2 -C 4 haloalkynylthio, -C OR 7, -C NR 6 R 7, -CR 6 NOR 7, -NR 6 R 7, -NR 6 OR 7, -NR 6 SO 2 R 7, -NR 6 C R 7, -NR 6 C OR 7, -NR 6 C NR 6 R 7 or -NCR 6 NR 6 R 7; Y 1 represents H, halogen, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, C 1 -C 6 haloalkoxy, C 2 -C 6 alkenyl or C 2 -C 6 haloalkenyl, or, when X 1 and Y 1 are taken together, represents -O(CH 2) n CH 2 -, or -O(CH 2) n O- wherein n = 1 or 2; and Z 1 represents H or halogen; R 3 and R 4 independently represent H, C 1 -C 6 alkyl, C 3 -C 6 alkenyl, C 3 -C 6 alkynyl, hydroxy, C 1 -C 6 alkoxy, amino, C 1 -C 6 acyl, C 1 -C 6 carboalkoxy, C 1 -C 6 alkylcarbamyl, C 1 -C 6 alkylsulfonyl, C 1 -C 6 trialkylsilyl or C 1 -C 6 dialkyl phosphonyl or R 3 and R 4 taken together with N represent a 5- or 6-membered saturated ring; and R 6 represents H, C 1 -C 4 alkyl or C 1 -C 4 haloalkyl; and R 7 represents C 1 -C 4 alkyl or C 1 -C 4 haloalkyl;