<![CDATA[Sandalwood (Santalum album L.) is a high-value endemic plant species in East Nusa Tenggara whose population is increasingly threatened by destructive stem disease complexes. This study aimed to isolate, characteristically identify based on macroscopic and microscopic morphology, and determine the pathogenicity of fungi inducing sandalwood stem diseases in North Central Timor Regency, specifically from Haulasi Village (634 m a.s.l.) and Sasi Village (395 m a.s.l.). Sampling was conducted on stem tissues exahibiting necrosis and stem canker symptoms, followed by isolation using Potato Dextrose Agar (PDA) media. From this research, six pure isolates were successfully obtained and identified into four genera: KJH1 and KJK1 (Trichoderma sp.), BBJ1 and BBJ2 (Fusarium sp.), BBJ3 (Phytophthora sp.), and BBJ4 (Botryodiplodia sp.). Pathogenicity testing at 30 days after inoculation (DAI) demonstrated that isolates BBJ1, BBJ2, BBJ3, and BBJ4 were pathogenic, successfully inducing necrosis symptoms characterized by blackish-brown stem tissue discolouration. Conversely, isolates KJH1 and KJK1 were non-pathogenic, presumably playing roles as secondary microflora or endophytic fungi. Successful re-isolation yielded pure cultures with phenotypic characteristics identical to the initial inocula. This confirms that Fusarium sp., Phytophthora sp., and Botryodiplodia sp. fully satisfy all criteria of Koch's Postulates as the primary causal agents of stem rot and stem canker diseases in sandalwood.]]>
