Adjuvants selectes from mon/ionic water/soluble mixed polyalkoxy-lated aliphatic alcohol surfactants, non ionic water soluble ethoxylated aliphatic alcohol surfactants, amine ethoxylates, and micronized polymeric waxes enhance the efficacy of fungicidal triazolopzrimidines of structural formula I. They can be incorporated into formulations of the fungicidal compounds or be added to spray mixtures (tank mix) as separately formualted additives in order to improve the efficacy and spectrum of these fungicides. This invention also provides fungicidal compositions of said triazolopzrimidines and adjuvants, as well as methods for their use in the control of photopathogenic fungi