Trifloxystrobin is a new strobilurin fungicide, active against a wide range of fungal plant pathogens. The present study shows that trifloxystrobin is highly effective in controlling powdery mildews on field-grown apple, mango and nectarine trees and rust disease on prune trees. In the majority of the field experiments conducted during 1998–1999, trifloxystrobin (at a concentration of 0.01–0.015% v/v) was superior to demethylation inhibitors (DMI fungicides) or sulphur. Trifloxystrobin was significantly (p<0.05) more effective than the DMI fungicide penconazole in controlling primary and secondary infections of powdery mildew on apple trees, and it provided 95–100% protection compared with non-treated trees. Similarly, trifloxystrobin was more effective than either myclobutanil or penconazole in controlling powdery mildew on fruit and leaves of nectarine trees. Trifloxystrobin provided the best control of powdery mildew on bloom clusters of mango, while sulphur, hexaconazole, and kresoxim-methyl were less effective. Trifloxystrobin effectively inhibited rust on prune trees and provided 98.0% protection, compared with the control. Trifloxystrobin is an excellent compound for efficient integration into control programs against fungal pathogens in apple, mango and stone fruit orchards.