부산대학교 도서관

Canker diseases of trees are caused by fungal pathogens, among them Botryosphaeria spp. is one important group. Botryosphaeriaceae is a genus-rich family in the Dothidiomycetes, containing numerous species with a cosmopolitan distribution. Some of the genera are important pathogens of fruit and woody trees causing symptoms such as leaf spot, dieback, stem-end rot, fruit rot, gummosis and cankers that can result in tree mortality. Most members of the Botryosphaeriaceae have a broad host range, and have been recognized as successful opportunistic pathogens that occasionally cause extensive disease symptoms when their plant hosts are subjected to unfavourable conditions. Common related diseases include dieback of Thuja orientalis, stem end rot of papaya and mango fruit, stem canker of guava, and gummosis of peach trees, plums and cheery trees. In recent years, trees emerged dieback, canker, gummosis and longitudinal crack symptoms frequently in Taiwan, for example, the canker and black tumors on Bombax ceiba and Gummosis on the bark of Melia azedarach, which are never been investigated or discussed by domestic research articles. Two fungal pathogens were isolated from theses two diseased samples and subjected to molecular identification, the results showed two Botryosphaeria spp., Lasiodiplodia theobromae and L. pseudotheobromae, are very likely responsible for the two diseases. Canker disease of Bombax ceiba occurs prevalently in Taiwan, the infection of the trunks and stems resulting in black tumors developed extensively, inaesthetic appearance, and may cause the decline of the host then can result in tree mortality at last. On the other hand, the relative species, L. pseudotheobromae, could be the pathogen that cause Gummosis of Melia azedarach. We can progress associated control research and draft health management strategy after verifying pathogens, which will contribute to reduce the occurrence of these diseases.