The invention relates to substituted triazolopyrimidines of formula (I), with the substituents as follows: R1, R2 = H, alkyl, haloalkyl, cycloalkyl, halocycloalkyl, alkenyl, haloalkenyl, cycloalkenyl, halocycloalkenyl, alkinyl, haloalkinyl, phenyl, naphthyl, or a five- or six-membered saturated, partially unsaturated or aromatic heterocycle, comprising one to four heteroatoms of the group O, N or S, R1 and R2 can, together with the nitrogen atom to which it is attached, form a five- or six-membered heterocycle or heteroaryl, bonded via N and containing one to three further heteroatoms from the group O, N and S as ring members, substituted as per the description, L1 = fluorine, chlorine or bromine, L2 = H, alkyl or alkoxy and X = halogen, cyano, alkyl, haloalkyl, alkoxy or haloalkoxy. The invention further relates to methods and intermediates for production of said compounds, agents comprising the same and use thereof for controlling fungal pests harmful to plants.