Incidence and severity of Ganoderma rot disease in tropical land-use systems and their virulence to palm oil.
Background and Objective: Ganoderma spp., have been reported as invasive tree pathogen and mostly reported in oil palm, however, information about the degradation in different land-use are limited. The rot disease caused by Ganoderma in the rainforest and agro plantation was investigated. In addition, this study was aimed to analyze the pathogenicity of Ganoderma infected forest and rubber trees to oil palm tree. Materials and Methods: Rot disease incidence and severity were measured in the rainforest, oil palm plantation and rubber plantation in two landscapes in Indonesia. The basidiocarps on infected trees were collected and the growth rate of Ganoderma on potato dextrose agar was measured. Selected Ganoderma from the forest, oil palm plantation and rubber plantation were tested for their virulence on oil palm seedling. Results: Ganoderma was a generalist tree pathogen since trees in different land-uses were infected. Interestingly, forest trees are more severe than mono plantations. Each Ganoderma has significantly different growth ability. When the virulence of Ganoderma tested in the oil palm seedling, only Ganoderma collected from oil palm plantation infected the oil palm seedlings with almost 100% in 10 weeks. Ganoderma from rubber plantation infected the oil palm seedlings very slow while the forest's Ganoderma did not infect the oil palm. Conclusion: Ganoderma is a wide range pathogen that potentially degraded woody trees in different land-uses. Although the mycelial of Ganoderma showed vary differ rapid growth, which may have related to the virulence, Ganoderma from forest and rubber trees performed less virulence to oil palm seedlings.