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Microscopic features of Dothiorella heterophyllae (ex-holotype, CMW 46458 = PPRI 25141). (A). Conidiomata formed on hardwood twig. (B). Vertical section of conidiomata. (C). Conidiomatal wall. (D). Conidia. (E, F). Conidiogenous cells and young conidia attached. (G). Colony on 2 % MEA showing optimum growth in the dark at 20 °C in 7 d. Scale bars: A = 500 μm; B = 100 μm; C, D = 25 μm; E, F = 10 μm.
Source publication
Acacia koa and A. heterophylla are commonly occurring native trees on the Hawaiian Islands and La Réunion, respectively. A recent phylogenetic study suggested that A. heterophylla renders A. koa paraphyletic, and that the former likely arose from the Hawaiian Islands around 1.4 million years ago. An intriguing question is whether their microbiota i...
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Citations
... A growing number of studies show that pathogens found associated with tree diseases in natural ecosystems are in many cases likely to be of exotic origin. 20,[24][25][26][27] The importance of tree health in natural forests has recently been highlighted by the accidental introduction of the polyphagous shot hole borer, Euwallacea fornicatus, and its fungal symbiont Fusarium euwallaceae. 28 The beetle is native to Asia and was first detected in South Africa in 2016, as part of a programme to survey botanical gardens for new and emerging pest risks. ...
South Africa is a country with very limited natural forest cover. Consequently, the timber and fibre needs of the country cannot be provided for from indigenous forest. It is largely for this reason that South Africa initially developed a highly productive plantation forest industry, which today makes a substantial contribution to the local economy. These plantations are based on non-native species of Eucalyptus, Pinus and Australian Acacia. In the early years of establishment, South African plantations were relatively free of pest and pathogen problems. But, over time, an increasing number of insects, fungi and bacteria have emerged as serious threats to the sustainability of the forestry industry. Numerous native pests and pathogens, especially insects, have adapted to these introduced tree species to cause damage or disease. The problem is compounded by the accidental introduction of non-native pests and pathogens, and this has been at a rapidly increasing rate over the past three decades. Some of these introduced pests and pathogens also threaten the fitness and even the survival of many indigenous South African tree species. Fortunately, South Africa has developed an impressive knowledge base and range of integrated management options to deal with these problems. This development was first driven by government programmes, and in more recent years by public–private partnerships between industry, universities and government. It is clear from the pattern of emergence of pests and pathogens in recent years that South Africa will deal with an increasing number of these problems and a continuously changing tree health environment. This requires robust investment in both quarantine and mitigation mechanisms to protect the country’s biodiversity as well as to ensure the sustainability of its wood and fibre industries.
Significance:
• This review about tree health in South Africa was in part inspired by the 2020 International Year of Plant Health. Plant health, and particularly tree health, is an important topic in regard to the sustainability of our forestry industry and conservation of our native forests. South Africa has been a leader in the field and this review highlights some of the achievements that researchers in the country, both past and present, have attained.
An extensive literature search was performed to review current knowledge about endophytic fungi isolated from plants included in the European Food Safety Authority (EFSA) dossier. The selected genera of plants were Acacia, Albizia, Bauhinia, Berberis, Caesalpinia, Cassia, Cornus, Hamamelis, Jasminus, Ligustrum, Lonicera, Nerium, and Robinia. A total of 120 fungal genera have been found in plant tissues originating from several countries. Bauhinia and Cornus showed the highest diversity of endophytes, whereas Hamamelis, Jasminus, Lonicera, and Robinia exhibited the lowest. The most frequently detected fungi were Aspergillus, Colletotrichum, Fusarium, Penicillium, Phyllosticta, and Alternaria. Plants and plant products represent an inoculum source of several mutualistic or pathogenic fungi, including quarantine pathogens. Thus, the movement of living organisms across continents during international trade represents a serious threat to ecosystems and biosecurity measures should be taken at a global level.
