Five tebuconazole and propiconazole quaternary salts were synthesized and studied for thermal stability, chem. structure, octanol/water partition coeff. and biol. activity against a fungal species of Fusarium culmorum, Microdochium nivale and Botrytis cinerea (concn. 10-1000 ppm). The activity was slightly lower than this of some corn, products used in crop protection.