The invention relates to 3-(pyridin-2-yl)-[1,2,4]-triazines of formula (I) and their use in the control of parasitic fungi and to herbicides that contain said compounds as an effective ingredient thereof. In formula (I), R1, R2 independently represent OH, halogen, NO2, NH2, C1-C8 alkyl, C1-C8 alkoxy, C1-C8 halogenalkyl, C1-C8 halogenalkoxy, C1-C8 alkylamino or di(C1-C8 alkyl)amino, or they form, together with the C atoms to which they are bound, a saturated five-, six- or seven-membered carbocycle or heterocycle, which, in addition to the carbon ring members, has one or two heteroatoms selected from oxygen or sulfur as the ring members, the carbocycle and the heterocycle being unsubstituted or having 1, 2, 3 or 4 C1-C4 alkyl groups as the substituents; R3 represents hydrogen, C1-C4 alkyl, C1-C4 alkoxy, C1-C4 halogenalkyl, C1-C4 halogenalkoxy, C3-C6 cycloalkyl, C3-C6 cycloalkylmethyl, or halogen; R4 represents hydrogen, C1-C4 alkyl, C1-C4 alkoxy, C1-C4 halogenalkyl, C1-C4 halogenalkoxy or halogen; R5 represents C1-C8 alkyl, C1-C8 halogenalkyl, C1-C8 alkoxy, C1-C8 halogenalkoxy, C3-C8 cycloalkyl, C3-C8 cycloalkyloxy, five- or six-membered heteroaryl, phenyl, phenoxy, benzyl, benzyloxy, five- or six-membered heteroarylmethyl or five- or six-membered heteroaryloxy, said cyclic groups being unsubstituted or having 1, 2, 3, 4 or 5 groups Ra.