Mardhiansyah, MWidyastuti, SMHarjono2015-03-232015-03-232015-03-23wahyu ari yenihttp://repository.unri.ac.id/xmlui/handle/123456789/6884The study was conducted to determine the control potensial of Trichoderma Spp. Against ganoderma sp in acacia mangium plantation; and to compare the inhibilition levels of two isolates of trichoderma sp : field isolate (T 62) and lab stock isolate (T13) (laboratory of forest health and protection, Facultaty of Foresty, Gajah Mada University) on Ganoderma sp. Trichoderma spp isolated T13 and T62 ware applied in pellete formulation. Pelletes were applied on seed bed with a rate of five pelletes per acacia seedling. Twelve months after transplanting, the plants were observed to determine the levels of Ganoderma infection. Our study results indicated that Trichoderma spp. Effection retes of the fugal pathogen on A.magium isolate T62 had a stronger inhibilition rate on ganoderma grawht compared to T13. Isolate T13 and T62 had supperession level of 95,9% and 91.3 % on Ganoderma sp in vitro respectivety : the colony growth of the isolatates after a-6 day incubation on SA growth medium indicated that isolate T62 grew better (65,5 cm ) compared to T13 (36.4 cm ). Competitive interaction berween T13 and T62 was also evident in the this experimentenTrichoderma sppGanoderma spAcacasia mangiumbiocontrolUR-Scientific Work Lecturer