Occurence, characterization and distribution of Brown Root Disease Fungus, Phellinus Noxius in Peninsular Malaysia Forest Plantations

Abstract

Brown Root Disease caused by Phellinus Noxius is considered as one of the major threats in majority of Hevea Brasiliensis. It can also kill forest plantations species such as T. Grandis, Khaya Ivorensis and A. Excelsa. However, little is known on the severity of Brown Root Disease (BRD) infection in Peninsular Malaysia forest plantations. Surveys for BRD were conducted randomly at 33 forest plantation sites in Peninsular Malaysia. Diseased samples were transported to the Pathology Laboratory at Forest Research Institute Malaysia (FRIM) for fungal isolation and identification. In the survey, BRD was occurred in 8 of 3 plantations (24.2%). It was found in 3, 2 and 3 monoculture plantations of T. Grandis, A. Excelsa and A. Mangiurn, respectively. In general, the disease incidence was low, ranging from 0.25%-4.37%. Infected trees occurred in solitary or patches and randomly distributed in the plantation. The study also found that poor land clearing and previous history of BRD in the plantations are the main contributing factors to the disease incidence. In the remaining plantations, majority of unhealthy trees were observed to be associated with abiotic stress. Fungus associated with BRD was identified as P. Noxius. The fungus often forms resupinate fruiting body with hard, crusted and dark brown characteristics. It was widely distributed in Peninsular Malaysia regardless the host species and geographic origins.