Faculty of Natural and Agricultural Sciences
School of Biological Sciences
Department of Genetics
Selected Highlights from Research Findings
One of the more fascinating but worrying discoveries in recent years by members of the Tree Protection Co-operative Programme (TPCP) at FABI is that many new disease and pest problems are being caused by native insects and microbes. The unexpected appearance of a serious wood-boring cossid moth on Eucalyptus during 2004 illustrates this worrying trend. Larvae of the insect were found and these were reared to the adult stage. This work led to the conclusion that the insect is the native cossid moth Coryphoderma tristis, also known as a Goat Moth due to the unpleasant odour associated with infestations. The recent damage caused by Coryphoderma tristis on E. nitens is sufficiently significant to the forestry industry to have necessitated an intensive study. Current activities include a search for the cause of the sudden host shift as well as to consider the moth's natural enemies. This will make it possible to formulate an effective pest management programme in the context of South African forestry practices.
Contact person: Prof MJ Wingfield.
Cryphonectria canker is one of the most serious diseases of Eucalyptus in South Africa. The disease has been known in the country for approximately 15 years and it is reasonably clear that it was not a problem prior to this time. Cryphonectria canker also occurs almost predominantly in warmer, sub-tropical regions of South Africa. Recent research conducted in this programme has focused on the distribution of the disease. Predictions have also been made concerning global warming and the likely extension of the range of this disease if temperatures in the country were to rise.
Intriguing and important results have continued to emerge concerning the origin of the Cryphonectria canker pathogen. This disease agent has been known in South Africa as Cryphonectria cubensis and the assumption has been that it was introduced into the country, either from Latin America or from South East Asia. During the last few years research in this programme has accumulated increasing evidence that the pathogen is native to South Africa. This has led to a change of name for the pathogen that is now known as Chrysoporthe austroafricana. The implications of this work are very significant. Certainly there is evidence to show that the fungus is more pathogenic than the fungus now known as Chrysoporthe cubensis. This fungus threatens Eucalyptus forestry in other parts of the world, including native Eucalyptus, potentially other Myrtaceae, in countries such as Australia. There is also a great danger of Chr. Cubensis being introduced into South Africa, and clearly all breeding and selection work done up until now is against a pathogen native to the country and will probably not apply to Chr. Cubensis.
Discovering that Chr. Cubensis (formerly C. cubensis) does not occur in South Africa has raised the question of the origin of this fungus. This is important to South Africa because such knowledge will increase our capacity to exclude the fungus from the country. Some early evidence has suggested that the origin of the pathogen might be South America, and that the fungus of the same name in South East Asia might represent a different species. As a result of research with a student from Colombia, we have gained added information supporting the view that Chr. Cubensis is probably native in South America. This work is not complete and is being continued through additional collections and intensive DNA sequence comparisons.
Contact person: Prof MJ Wingfield.
Cryphonectria canker is one of the most serious diseases of Eucalyptus in South Africa. The disease has been known in the country for approximately 15 years and it is reasonably clear that it was not a problem prior to this time. Cryphonectria canker also occurs almost predominantly in warmer, sub-tropical regions of South Africa. Recent research conducted in this programme has focused on the distribution of the disease. Predictions have also been made concerning global warming and the likely extension of the range of this disease if temperatures in the country were to rise.
Intriguing and important results have continued to emerge concerning the origin of the Cryphonectria canker pathogen. This disease agent has been known in South Africa as Cryphonectria cubensis and the assumption has been that it was introduced into the country, either from Latin America or from South East Asia. During the last few years research in this programme has accumulated increasing evidence that the pathogen is native to South Africa. This has led to a change of name for the pathogen that is now known as Chrysoporthe austroafricana. The implications of this work are very significant. Certainly there is evidence to show that the fungus is more pathogenic than the fungus now known as Chrysoporthe cubensis. This fungus threatens Eucalyptus forestry in other parts of the world, including native Eucalyptus, potentially other Myrtaceae, in countries such as Australia. There is also a great danger of Chr. Cubensis being introduced into South Africa, and clearly all breeding and selection work done up until now is against a pathogen native to the country and will probably not apply to Chr. Cubensis.
Discovering that Chr. Cubensis (formerly C. cubensis) does not occur in South Africa has raised the question of the origin of this fungus. This is important to South Africa because such knowledge will increase our capacity to exclude the fungus from the country. Some early evidence has suggested that the origin of the pathogen might be South America, and that the fungus of the same name in South East Asia might represent a different species. As a result of research with a student from Colombia, we have gained added information supporting the view that Chr. Cubensis is probably native in South America. This work is not complete and is being continued through additional collections and intensive DNA sequence comparisons.
Contact person: Prof BD Wingfield.
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