Teratosphaeria nubilosa is one of the most important
pathogens of Eucalyptus in commercial plantations. A
recent study has shown that the fungus, hitherto treated under
this name, represents a complex of two species. Teratosphaeria
pseudonubilosa sp. nov. is, therefore, described as a closely
related and morphologically similar, sister species to T.
nubilosa. T. pseudonubilosa infects leaves of commercially
propagated and native E. globulus trees in forests of Victoria
and Tasmania (Australia), where it is native. It has also been
introduced into Western Australia and New Zealand where it
causes serious defoliation of susceptible trees. A revised geographical
distribution of T. nubilosa sensu stricto and T.
pseudonubilosa is provided to assist in the future management
of the diseases that they cause.