The present invention relates to pyridazine compounds of formulae I or II and the salts and N-oxides thereof, wherein A is a substituted or unsubstituted isoxazole or isothiazole radical; V is C(Rv) or N; W is C(Rw) or N; with the proviso that either V or W is N; Rt, Ru, Rv, Rw are H, halogen, C1-C4-alkyl and the like; X1 is S, O or NR1a, wherein R1a is selected H, C1-C10-alkyl and the like; X2 is OR2a, NR2bR2c, S(O)mR2d, wherein m is 0, 1 or 2, R2a is C1-C4-alkyl, C1-C4-haloalkyl and the like, R2b, R2c are H, C1-C4-alkyl, C1-C4-haloalkyl and the like, or R2b and R2c together with the nitrogen atom to which they are bound form a heterocycle, and R2d is C1-C4-alkyl, C1-C4-haloalkyl, C3-C6-cycloalkyl and the like; and R1 is H, CN, C1-C10-alkyl and the like. The present invention further relates to a method for controlling invertebrate pests, to a method for protecting plant propagation material and/or the plants which grow therefrom, to plant propagation material, comprising at least one compound according to the present invention, to a method for treating or protecting an animal from infestation or infection by parasites and to an agricultural composition containing at least one compound according to the present invention.