The effects of induced crude antifungal compounds from cocoa pods infected with Phytophthora palmivora were investigated against Aspergillus flavus, Aspergillus glaucus, Aspergillus niger, Botrydiplodia theobromae and P. palmivora using radial mycelial growth and dry mycelial weight assay. Also, the effect of the antifungal compounds was compared with commercial fungicide (Funguran®). In this study, the test fungi exhibited differential sensitivities to the antifungal effect of the induced extract. The result of the radial mycelial growth assay in millimeters revealed that A. glaucus had radial mycelial growth that varied from 23.0±0.02 (50mg/ml) to 17.0±0.01 (200mg/ml), while A. niger had a growth of 23.0±0.05 (50mg/ml) to 13.0±0.02 (200mg/ml). Also, A. flavus was with radial mycelial growth of 28.0±0.02 (50mg/ml) to 12.0±0.05 (200mg/ml). B. theobromae had a mycelial growth of 32.0±0.15 (50mg/ml) to 17.0±0.03. Similarly, P. palmivora had a radial mycelial growth of 3.0±0.12 (50mg/ml) and at the concentrations of 100mg/ml and above, the radial mycelial growth of the fungus was completely inhibited. On the other hand, the result of the dry mycelial weight assay in milligrams showed that A. niger had a dry mycelial weight that ranged from 340.0±0.15 (50mg/ml) to 160.0±0.01 (200mg/ml) while A. flavus had a weight of 410.0±0.25 (50mg/ml) to 280.0±0.03 (200mg/ml). Similarly, B. theobromae had a mycelial weight of 380.0±0.10 (50mg/ml) to 190.0±0.05 (200mg/ml). P. palmivora was with a dry mycelial weight of 40.0±0.20 at 50mg/ml but was completely inhibited at all other concentrations. The conventional fungicide was found to exhibit high antifungal effects on the test organisms. The effect of the induced extract compared favourably with that of the commercial fungicide in this study. Therefore, induced compounds from infected cocoa pods can be used in the development of fungicides for crop protection.
Full conference title:
- ASM 113th (2013)