The invention relates to 5-alkyl-7-aminotriazolopyrimidines of the formula (I) and to the salts thereof. In said formula substituents have the following meanings: R1 and R2 each is a hydrogen atom or a group of alkyl, alcenyl, haloalkyl, cycloalky, phenyl or naphtyle, saturated, unstaturated or aromatic heterocycle having from five to six members which contain from one to four nitrogen atoms or one to three nitrogen atoms and one sulfur or oxygen atom, or R1 and R2 can from together with a connecting them nitrogen atom a cycle of 5 to 6 members containing from one to four nitrogen atoms or from one to three nitrogen atoms and one sulfur or oxygen atom, R3 is a cycloalkyl or bicycloalkyl group, R1, R2 and R3 can be substituted in conformity with a description, and X is an alkyl or alkyl halide group. The inventive methods and intermediary products necessary for producing said compounds, agents containing them and the use therefore for fighting against harmful mushroom are also disclosed.