Mycosphaerella tasmaniensis is newly described from Mycosphaerella leaf blotch symptoms occurring on Eucalyptus nitens in Tasmania, Australia. Single ascospore cultures produced a Mycovellosiella anamorph, described here as M. tasmaniensis. Both states occurred together, as well as separately on leaf spots. Phaeophleospora epicoccoides (=Kirramyces epicoccoides) is commonly associated with leaf spots of Eucalyptus spp. in Australia. The teleomorph, Mycosphaerella suttoniae, previously known only from Indonesia, was also collected on E. grandis leaves from Australia. A Cylindrocladium leaf blight disease of young E. grandis trees in Indonesia was found to be associated with a new species of Calonectria. Calonectria multiseptata and its anamorph Cylindrocladium multiseptatum is newly described and distinguished from other species based on their larger, multi-septate ascospores and conidia.