Isothiazoline compounds of the formula 1.3 wherein B 1, B 2 and B 3 are each independently CR 2; R 1 is selected from C 1 -C 4 -haloalkyl and -C(=O)OR 15, wherein R 15 is C 1 -C 4 -alkyl; R 2 is selected from hydrogen, halogen and C 1 -C 2 -haloalkyl; R 3a and R 3b are selected, independently of each other, from hydrogen and halogen; R 4 is selected from hydrogen, halogen, cyano, C 1 -C 4 -alkyl, C 1 -C 4 -haloalkyl, C 3 -C 5 -cycloalkyl, C 3 -C 5 -halocycloalkyl, C 2 -C 4 -alkenyl, C 2 -C 4 -haloalkenyl, C 2 -C 4 -alkynyl, C 2 -C 4 -haloalkynyl, C 1 -C 4 -alkoxy, C 1 -C 4 -haloalkoxy, C 1 -C 4 -alkylthio and C 1 -C 4 -haloalkylthio; R 5 is selected from hydrogen, C 1 -C 4 -alkyl and C 1 -C 4 -haloalkyl; R 6 is -C(=O)R 7; R 7 is selected from the group consisting of hydrogen, C 1 -C 6 -alkyl, C 1 -C 6 -haloalkyl, C 2 -C 6 -alkenyl, C 2 -C 6 -haloalkenyl, C 2 -C 6 -alkynyl, C 2 -C 6 -haloalkynyl, C 3 -C 8 -cycloalkyl, C 3 -C 8 -halocycloalkyl, C 3 -C 8 -cycloalkenyl, C 3 -C 8 -halocycloalkenyl, where the aliphatic and cycloaliphatic moieties in the ten last-mentioned radicals may be substituted by one or more radicals R 13; -OR 9, -S n R 9, -N(R 10a)R 10b, phenyl, optionally substituted with 1, 2, 3, 4 or 5 substituents R 16, and a heterocyclic ring selected from E-1 to E-3, E-44 and E-49 where k is 0, 1, 2 or 3; and n is 0, 1 or 2; R 9 is selected from hydrogen, C 1 -C 6 -alkyl, C 1 -C 6 -haloalkyl, C 3 -C 8 -cycloalkyl, C 3 -C 8 -halocycloalkyl, C 3 -C 8 -cycloalkyl-C 1 -C 4 -alkyl-, C 2 -C 6 -alkenyl, C 2 -C 6 -haloalkenyl, C 2 -C 6 -alkynyl and C 2 -C 6 -haloalkynyl; R 10a and R 10b, independently of each other, are selected from the group consisting of hydrogen, C 1 -C 6 -alkyl and C 1 -C 6 -haloalkyl; R 13 is selected from cyano, C 1 -C 6 -alkoxy, C 1 -C 6 -haloalkoxy, C 1 -C 6 -alkylthio, C 1 -C 6 -haloalkylthio, C 1 -C 6 -alkylsulfinyl, C 1 -C 6 -haloalkylsulfinyl, C 1 -C 6 -alkylsulfonyl, C 1 -C 6 -haloalkylsulfonyl and C 3 -C 8 -cycloalkyl which may be unsubstituted, partially or fully halogenated and/or may carry a cyano radical; and R 16 is independently selected from the group consisting of halogen, cyano, nitro, C 1 -C 4 -alkyl, C 1 -C 4 -haloalkyl, C 1 -C 4 -alkoxy, C 1 -C 4 -haloalkoxy, C 1 -C 4 -alkylthio, C 1 -C 4 -haloalkylthio, C 1 -C 4 -alkylsulfinyl, C 1 -C 4 -haloalkylsulfinyl, C 1 -C 4 -alkylsulfonyl, C 1 -C 4 -haloalkylsulfonyl, C 3 -C 6 -cycloalkyl, C 3 -C 6 -halocycloalkyl, C 2 -C 4 -alkenyl, C 2 -C 4 -haloalkenyl, C 2 -C 4 -alkenyl, C 2 -C 4 -haloalkenyl, C 2 -C 4 -alkynyl, C 2 -C 4 -haloalkynyl, C 1 -C 4 -alkylcarbonyl, C 1 -C 4 -haloalkylcarbonyl, aminocarbonyl, C 1 -C 4 -alkylaminocarbonyl and di-(C 1 -C 4 -alkyl)aminocarbonyl; or two R 16 present on the same carbon atom of a saturated ring may form together =O or =S and the N-oxides, stereoisomers and agriculturally or veterinarily acceptable salts thereof. B 1, B 2 and B 3 are each independently CR 2; R 1 is selected from C 1 -C 4 -haloalkyl and -C(=O)OR 15, wherein R 15 is C 1 -C 4 -alkyl; R 2 is selected from hydrogen, halogen and C 1 -C 2 -haloalkyl; R 3a and R 3b are selected, independently of each other, from hydrogen and halogen; R 4 is selected from hydrogen, halogen, cyano, C 1 -C 4 -alkyl, C 1 -C 4 -haloalkyl, C 3 -C 5 -cycloalkyl, C 3 -C 5 -halocycloalkyl, C 2 -C 4 -alkenyl, C 2 -C 4 -haloalkenyl, C 2 -C 4 -alkynyl, C 2 -C 4 -haloalkynyl, C 1 -C 4 -alkoxy, C 1 -C 4 -haloalkoxy, C 1 -C 4 -alkylthio and C 1 -C 4 -haloalkylthio; R 5 is selected from hydrogen, C 1 -C 4 -alkyl and C 1 -C 4 -haloalkyl; R 6 is -C(=O)R 7; R 7 is selected from the group consisting of hydrogen, C 1 -C 6 -alkyl, C 1 -C 6 -haloalkyl, C 2 -C 6 -alkenyl, C 2 -C 6 -haloalkenyl, C 2 -C 6 -alkynyl, C 2 -C 6 -haloalkynyl, C 3 -C 8 -cycloalkyl, C 3 -C 8 -halocycloalkyl, C 3 -C 8 -cycloalkenyl, C 3 -C 8 -halocycloalkenyl, where the aliphatic and cycloaliphatic moieties in the ten last-mentioned radicals may be substituted by one or more radicals R 13; -OR 9, -S n R 9, -N(R 10a)R 10b, where k is 0, 1, 2 or 3; and n is 0, 1 or 2; R 9 is selected from hydrogen, C 1 -C 6 -alkyl, C 1 -C 6 -haloalkyl, C 3 -C 8 -cycloalkyl, C 3 -C 8 -halocycloalkyl, C 3 -C 8 -cycloalkyl-C 1 -C 4 -alkyl-, C 2 -C 6 -alkenyl, C 2 -C 6 -haloalkenyl, C 2 -C 6 -alkynyl and C 2 -C 6 -haloalkynyl; R 10a and R 10b, independently of each other, are selected from the group consisting of hydrogen, C 1 -C 6 -alkyl and C 1 -C 6 -haloalkyl; R 13 is selected from cyano, C 1 -C 6 -alkoxy, C 1 -C 6 -haloalkoxy, C 1 -C 6 -alkylthio, C 1 -C 6 -haloalkylthio, C 1 -C 6 -alkylsulfinyl, C 1 -C 6 -haloalkylsulfinyl, C 1 -C 6 -alkylsulfonyl, C 1 -C 6 -haloalkylsulfonyl and C 3 -C 8 -cycloalkyl which may be unsubstituted, partially or fully halogenated and/or may carry a cyano radical; and R 16 is independently selected from the group consisting of halogen, cyano, nitro, C 1 -C 4 -alkyl, C 1 -C 4 -haloalkyl, C 1 -C 4 -alkoxy, C 1 -C 4 -haloalkoxy, C 1 -C 4 -alkylthio, C 1 -C 4 -haloalkylthio, C 1 -C 4 -alkylsulfinyl, C 1 -C 4 -haloalkylsulfinyl, C 1 -C 4 -alkylsulfonyl, C 1 -C 4 -haloalkylsulfonyl, C 3 -C 6 -cycloalkyl, C 3 -C 6 -halocycloalkyl, C 2 -C 4 -alkenyl, C 2 -C 4 -haloalkenyl, C 2 -C 4 -alkenyl, C 2 -C 4 -haloalkenyl, C 2 -C 4 -alkynyl, C 2 -C 4 -haloalkynyl, C 1 -C 4 -alkylcarbonyl, C 1 -C 4 -haloalkylcarbonyl, aminocarbonyl, C 1 -C 4 -alkylaminocarbonyl and di-(C 1 -C 4 -alkyl)aminocarbonyl; or two R 16 present on the same carbon atom of a saturated ring may form together =O or =S and the N-oxides, stereoisomers and agriculturally or veterinarily acceptable salts thereof.