The commercially important mountain ash forests of the Central Highlands of Victoria provide habitats for at least two species of phasmatids (stick insects), one of which (Didymuria violescens) has potential for severe defoliation over large areas. Such defoliation often results in premature tree death. In the summer of 1960/61, infestation of phasmatids first appeared in stands near Powelltown, though stands in other parts of the Central Highlands were also attacked. As a result of this threat to the immature ash resource, detailed studies on the biology and epidemiology of phasmatids were undertaken. This work, which is reported by Neumann et al. (1977), led to the development of an effective and safe control strategy.
Much has been said and written about the potential impact of the cinnamon fungus Phytophthora cinnamomi on native forests in parts of Australia. Particular attention has been focused on the jarrah forests of Western Australia, and their research provided a pace setter for the rest of Australia. It was also detected in some rain forests in Queensland, and the mixed eucalypt forests along the coastal regions of Victoria (especially east Gippsland). About 1000 ha of dieback and tree decline were observed in the coastal forests of east Gippsland in the 1950s, but the fungus was not isolated in these forests until 1969. Soon after (1970/71), acute dieback occurred over significant areas of these coastal forests (Marks and Idczak, 1977). As the type of injury sustained by trees varied considerably, it became evident at this time that, inter alia, disease expression depended on species, soil type, elevation and general climatic conditions. Exhaustive research followed the events of the 1960s and early 1970s.