ANTIMICROBIAL ACTIVITY OF ELAEIS GUINEENSIS LEAF EXTRACT AGAINST GANODERMA BONINENSE OF OIL PALM BASAL STEM ROT

Basal stem rot (BSR) which is caused by Ganoderma boninense is the most serious disease faced by oil palm Elaeis guineensis in Malaysia. Hitherto, many control measures such as cultural practices, fungicides, and biocontrol agents were attempted, yet, the result were unsatisfactory. This study was conducted to investigate potential antimicrobial properties in oil palm leaf extract against G. boninense. Oil palm leaf were extracted with different solvents namely methanol, acetone, chloroform and petroleum ether. The antimicrobial activities and fungitoxicity of leaf extracts against G. boninense were expressed in inhibition of mycelia growth of G. boninense on Potato Dextrose Agar (PDA) incorporated with the four different solvent leaf extracts with range concentration of 0-40 mg ml(-1). Acetone leaf extract was found to be very fungitoxic to G. boninense at concentration of 40 mg ml(-1), the highest concentration tested in this study. Methanol and petroleum ether leaf extracts were having inhibitory effect with 40 mg mL(-1)in comparison to the absolute control. Further separation of active bioactive compounds was conducted using thin layer chromatography (TLC) bioassay for methanol and acetone leaf extracts. Acetone extract was found to possess good antifungal activity with properties of R-f 0.09, 0.21, 0.24, and 0.60 compared to methanol extract, which only showed inhibition at R(f)0.74 against Aspergillus niger. The Rf values suggested that potential antimicrobial compound might be mixtures of polar and non-polar properties. The results suggested oil palm leaf extract might potentially explore as an important allelopathic agent against Ganoderma boninense.