Anthracnose leaf disease in rubber trees, caused by the attack of Colletotrichum gloeosporioides, have led to the serious decline in natural rubber production. Continuous usage of synthetic fungicide leave the toxic residues that harm the surrounding animals and plants and are not environmentally friendly. It needs a better solution with organic products that are safer, more effective and biodegradable. Piper species could be considered as a source of new natural products with potential

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... al activities. Thus, the research aimed to investigate the effect of leaf extracts from Piper betle, P.porphyrophyllum and P.aduncumin inhibiting the growth of C. gloeosporioides from rubber trees in vitro. Of the three Piper species, the crude methanolic extract of P. porphyrophyllum leaves shows the highest growth inhibition percentage (83.62%), followed by P. aduncum L. (79,38 %), P. betle (76.39%). In further examination on the leaf extract of Piper in various solvents, we find that the nhexane extract of P.aduncumhas the best performance in inhibiting the growth of C. gloeosporioides (GIP of 92.72%); it also beats the performance of Benomyl, a commercial fungicide, at the same concentration. The 50% percentage of growth inhibition (MIC 50 ) of this n-hexane extract towards C. gloeosporioides is reached at a very low concentration, 32 mg/L, while the MIC 90 is reached at concentration of 799 mg/mL. The results suggest that the n-hexane leaf extract of P. aduncum is a potential candidate for anti-Colletotrichum agent.