Antifungal Activity of Piper caninum against Pyricularia oryzae Cav. the Cause of Rice Blast Disease on Rice

摘要

Rice blast caused by Pyricularia oryzae Cav.is one of important and destructive disease on rice in most areas where susceptible rice cultivars are grown. This study was done in order to find alternative measure to control the disease by using leaf extract of Piper caninum Blume. Antifungal activity of P. caninum against P. oryzae was done under laboratory condition on potato dextrose agar (PDA) medium. Results of this study showed that the crude extract of P. caninum exhibited a very strong inhibitory activity against P. oryzae with diameter of inhibition zone by 44 mm. Minimum inhibitory concentration (MIC) of this extract was 0.5% (w/v). Treatment with leaf extract of P. caninum significantly (P<0.05) inhibited fungal radial growth, spores formation, and biomass formation. The growth inhibition resulted from this extract is due to the lysis of fungal cells indicated by the zize of mycelia, in which the size of mycelia treated with extract is obviously smaller than that of control. It is necessary to purify and identify the substances in the leaf extract of P. caninum that responsible the most for the antifungal activity against P. oryzae. In addition, a field trial is necessary to be done to evaluate the effectiveness of the leaf extract of P. caninum to control rice blast disease under field condition. Keywords : Piper caninum, rice blast disease, antifungal activity, cell lysis