Study On Pathogen Of The Acacia Mangium Heart Rot Disease

In order to understand occurrence and development regularity of the disease, and provide reference for control measurement, this study, taking the Acacia mangium forests as object, investigate the incidence and symptom of heart rot of Acacia mangium forests in some forest farm of Guangdong and Guangxi, collect the diseased tissue of heart rot in early stage and test pathogenicity of the isolation, and identify the species of the pathogenic fungi based on their morphological and morlecular charactesiticsThe incidence of the heart rot of Acacia mangium was 348%. Invasion for pathogen was mainly through dead and broken branches and unhealed wounds. Appearance symptoms can not be seen at initial stage of heart rot. Three types of rotting, puce and fibrous rotting, brown and powdery rotting, and white and pongy rotting was observered with the development of wood rotting. The edge of cross section of duramen was irregularly undulant, and turned into suborbicular or irregular rotten cavity in serious cases, the basidiocarp of wood rotting fungus formed in rotting trunk and stump. The disease's occurrence not only associated with the tree's age, but also with the climate of planting areas and aspect and position of the slope.36 samples of a heart rot disease of Acacia mangium were collected from stands at Long Yandong forest farm in Guangdong Province. More than 10 species of fungi, among which 3 were basidiacota fungi. Inoculation with these 3 basidiacota fungi to 1-year-old branch on 6-year-old living tree of Acacia mangium and wood block of Acacia mangium in culture dish, showed the pith of branch macerated and turn brown, and wood block was rot, suggesting 3 basidiacota fungi were the pathogenic fungi.3 basidiacota fungi were amplified by PCR technique with universal primers of fungi, and the sequences of the internal transcribed spacer of their ribosomal DNA were further compared with that in GenBank. Combined with their cultural characteristics, the 3 pathogenic fungi were Phanerochaete avllanea, Peniophora aurantiaca, and Phlebia brevispora. The incidence of disease and age related not only to plant the regional climate, slope aspect on the incidence of disease has a direct relationship.Nine kinds of sporocarps were collected from the weakened plants affected by the heart rot disease of Acacia mangium forests in guangzhou, xinhui and jiangmen of Guangdong, including Coriolopsis aspera(Jungh.) Teng, Ganoderma australe(Fr.) Pat., Hyphodontia flavipora (Cooke) Sheng H. Wu, Perenniporia ochroleuca (Berk.) Ryvarden, Perenniporia tephropora(Mont.) Ryvarden, Pycnoporus sanguineus (L.) Murrill, Trametes hirsuta(Wulfen) Pilat, Trametes orientalis (Yasuda) Imazeki, Lentinus infundibuliformis Berk.& Br., of which Coriolopsis aspera, Perenniporia ochroleuca, Perenniporia tephropora can lead to heart rot.