The invention relates to 7-alkenylamino-triazolopyrimidines of formula (I) wherein the substituents have the following meaning: L represents halogen, alkyl, halogenalkyl, alkoxy, amino, NHR or NR2; R represents alkyl or alkyl-carbonyl; m represents 1, 2, 3, 4 or 5; X represents halogen, cyano, alkyl, halogenalkyl or alkoxy; R1 represents alkyl or halogenalkyl; R2 represents hydrogen, alkyl or halogenalkyl; R3 represents alkenyl which is unsubstituted or partially or totally halogenated or can be substituted according to the description; R4 represents hydrogen or alkyl, R3 and R4 can form, together with the nitrogen atom whereon they are bound, a five or six-membered unsaturated ring which can be interrupted by an atom from the groups O, N and S and/or can include one or several substituents. The invention also relates to methods for producing said compounds, agents containing said compounds and the use thereof in controlling plant pathogenic harmful fungi.