Pathogenicity performance of Ceratocystis isolates obtained from Pahang against Acacia Mangium seedlings

Abstract

Wilt Disease caused by Ceratocystis sp. in Acacia Mangium plantations is considered as a new emergence scenario in Malaysia. This disease was first reported in 2011 in Eastern Sabah. Impact of the disease was enormous where thousand hectares of A. Mangium plantation at Eastern Sabah have been cleared (Brawner et al. 2015). Recently, the disease was also found to occur in several A. Mangiurn plantations in Peninsular Malaysia as well as in Sarawak. In Indonesia and Vietnam the disease has been declared as major threat to Acacia plantations due to serious damage of the tree stand and difficult to control. Several species of Ceratocystis have been identified to cause wilt disease of A. Mangium such as Ceratocystis Manginecans, Ceratocystis fimbriata and Ceratocystis acaciivora. In general, the genus Ceratocystis is well known as wound pathogen that often cause Cankers and Vascular Wilt Disease (Kile 1993). Trees infected by the pathogen can be recognized by wilting of leaves, presence of Gurnrnosis, Discolouration in wood and sunken stem (Tarigan et al. 2011, Morris et al. 1993; Bakshi 1951). Other than Acacias, this pathogen was also reported destructive to mango (Van Wyk et al. 2007), eucalyptus (Barnes et al. 2003; Roux and Wingfield, 2009), kiwi (Piveta et al. 2013) and sweet potato (Engelbrecht and Harrington, 2005). Since A. Mangium is the most planted forest plantation tree species in the country (Mohd. Farid et al. 2015), the presence of this pathogen in the plantations could be inconvenient because it's very difficult and costly to control. This study was conducted to determine the causal agent of A. Mangium wilt disease as well as to assess the most virulent isolates of Ceratocystis spp. obtained from Kemasul Forest Plantation against A. Mangium.