23 years of research on Teratosphaeria leaf blight of Eucalyptus

Abstract

In Australia, during the course of the last two decades, plantation area of Eucalyptus has expanded dramatically. One of the most important threats to these trees, and to the forest industries they sustain, is a complex of fungal diseases broadly treated as Teratosphaeria Leaf Blight. The aim of this review is to summarise some of the most important findings relating to Teratosphaeria spp. (previously Kirramyces) associated with leaf and shoot blight of Eucalyptus. The review spans a period of 23 years since the description of the aptly named Teratosphaeria destructans. Six species of Teratosphaeria are associated with leaf and shoot blights of Eucalyptus and these are T. destructans, T. eucalypti, T. novaehollandiae, T. pseudoeucalypti, T. viscida and T. tiwiana. With the exception of T. destructans, all of these species have been found in Australia. Based on the damage they cause, the most significant of these fungi are T. destructans, T. pseudoeucalypti and T. viscida. Teratosphaeria viscida has been found only in the tropics of eastern Australia, while T. destructans and T. pseudoeucalypti have spread globally; T. destructans throughout Asia and South Africa and T. pseudoeucalypti into South America. Factors driving the development of these diseases have included the establishment of plantations adjacent to native eucalypt forests in Australia and planting on sites not favourable to the growth of the host trees. These factors, in conjunction with a lack of selection for resistance to emerging pathogens, lack of resilience to disease in monocultures, and the movement of pathogens with planting stock and seeds around the globe have led to substantial losses. Based on the Teratosphaeria leaf blight example, it is clear that more effective forest management and more stringent biosecurity measurements will be a required to sustain eucalypt plantations globally.