Ceratocystis sp. causes crown wilt of Acacia spp. planted in some ecological zones of Vietnam
Thu, P.Q., Qynh, D.N. and Dell, B. (2012) Ceratocystis sp. causes crown wilt of Acacia spp. planted in some ecological zones of Vietnam. In: Proceeding of International Conference on The Impacts of Climate Change to Forest Pests and Diseases in The Tropics, 8 - 10 October, Yogyakarta, Indonesia pp. 38-44.
The plantation area in Vietnam of Acacia auriculiformis, A. mangium and their hybrid has expanded greatly in the last decade. Recently, a new stem canker disease causing symptoms of crown wilt, followed by wood discoloration then death of infected trees has occurred in many ecological zones. Ascomata were obtained by incubating discolored wood pieces in moist chambers or by carrot baiting. Isolates of fungi were obtained on PDA medium by taking spores emerging from the tips of ascomata necks. Ceratocystis was identified based on ascospore morphology and conidial types. Twenty six isolates of Ceratocystis were used for pathogenicity assessment on 8-month old seedlings of A. mangium in a nursery, with 5 seedlings per isolate. Stems were inoculated by inserting an 8 mm diameter PDA plug covered with 15-day old mycelia onto the cambium about 50 cm above the ground. Five seedlings were inoculated with sterile PDA plugs to serve as the control. The wounds and plugs were sealed with parafilm to protect them against desiccation and rain. After 60 days of inoculation, based on lesion development and tree death, the pathogenicity of the isolates were identified: 2 isolates (AA8, AMH12) nil, 4 isolates (AAHX1, AMH40, AMD26, AHDL1) low, 4 isolates (AA22, AMH9, AMMB7, AHXL3) moderate, 3 isolates (AMBL3, AMPL2, AMH5) high, and 13 isolates (AA54, AA62, AMH24, AMH26, AMH41, AMHX1, AMQN1, AMBL4, AHBB1, AHBD1, AHBP1, AHXL1 and AHXL2) very high level of pathogenicity causing plant death. This is the first record of Ceratocystis causing damage to Acacia plantations in Vietnam. The origin of the pathogen is unknown. Work is progressing to determine whether the species is the same as that known to cause damage to A. mangium plantations in Indonesia.
|Publication Type:||Conference Paper|
|Murdoch Affiliation:||Centre of Excellence for Climate Change and Forest and Woodland Health
School of Biological Sciences and Biotechnology
|Notes:||In: Mohammed, C., Beadle, C., Roux, J. and Rahayu, S. (eds) 2012. Proceeding of International Conference on The Impacts of Climate Change to Forest Pests and Diseases in The Tropics, 8 - 10 October, Yogyakarta, Indonesia. Faculty of Forestry, Universitas Gadjah Mada, pp 79-84|
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