<i>In</i> <i>Vitro</i> Effect of Indigenous Antagonistic Microorganisms of Dibombari Oil Palm Plantation on in <i>Ganoderma</i> <i>sp.</i><i>,</i> Principal Agent of Basal Stem Rot of Oil Pa

Ganoderma sp. is the main fungus that affects the oil palm, causing the basal stem rot. This fungus can lead to a significant economic loss of 43% in an oil palm plantation. To address this challenge, the management strategy focuses on developing a cost-effective and environmentally friendly integrated control method. Special emphasis has been placed on the use of indigenous antagonistic microorganisms. To achieve this, the microbial biodiversity in oil palm has been explored. Fungi and bacteria have been isolated from soil beneath their roots. Additionally, Ganoderma sp. has been isolated from fruiting bodies located at the base of infected oil palms. The antagonistic effect of these microorganisms on Ganoderma sp. has been assessed in vitro. The results showed that in dual culture test with Ganoderma sp., two microorganisms, the fungus (CS1) and the bacterium (IBS6) showed fungicidal effects with PIRG value of 66% and 72% respectively. Furthermore, the molecular identification revealed that fungus (CS1) exhibits a 99.79% similarity with Trichoderma virens, while the bacterium (IBS6) shows 100% similarity with Bacillus subtilis.