Source: SEAMEO BIOTROP's Research Grant | 2015
Palm oil (Elaeis guineensis) is one of Indonesia's strategic commodities at the moment. Basal stem rot disease (BSR) which is caused by the fungus Ganoderma boninense is the biggest disease problem in palm oil plantation. Ganoderma attack has a major economic impact on the oil palm plantations. This study aims to determine the composition of bacteria in the rhizosphere of healthy oil palm growing areas and sick plant due to G. boninense attack, to select the rhizosphere bacteria that could stimulate plant growth and stable with the aplication of lemongrass essential oil application. Application of microorganisms is expected to improve the response of plant growth, combined with the biofungicide from lemongrass essential oil that previous research showed a good ability to inhibit the growth of G. boninense. Combination of this treatment is expected to solve the problem on oil palm plantations due to G. boninense attack. The results showed comparison of bacteria species composition of phosphate soluble bacteria, producing siderophores and NFB different at each level of the health condition of the land by plants based on G.boninense attack. Isolates that affected by G.boninense attack on plant is phosphate soluble bacteria and siderophore bacteria. The healthier condition of land and crops corelated with higher the population of phosphate soluble bacteria and siderophore bacteria. The health condition of the land and the plants do not affect the composition of the NFB. Some types phosphate soluble bacteria, producing siderophores and NFB has good stability against application of lemongrass essential oils so the application of biofungicide based lemongrass essential oils does not inhibit the growth of bacteria naturally found in the rhizosphere of plants. From a series of tests best isolates is 26 PSB H16. This isolate have the ability to stimulate the plant growth and high stability against application of essential oils and is able to inhibit the growth of G.boninense. Use of molasses as growth medium of rhizosphere bacteria more effective and economical than the use of commercial medium.