Aims: The present study was designed to evaluate in vitro antifungal activity of plant extracts against Curvularia sp., a causative agent of leaf blotch in local purple sweet potato crops. Methodology and results: The plants were selected on the basis of commonly used traditional remedies. Various dilutions, 1/2, 1/4, 1/6, 1/8 and 1/10 of black pepper, garden croton, garlic, tobacco and turmeric extracts were used for screening. The lesion characteristics on purple sweet potato leaves were collected from plots in MARDI Bachok. The “poisoning agar technique method” was used to get the antifungal activity. The results of antifungal activities were reported in terms of inhibition of mycelial growth of the test fungus. Out of five types of plant extracts used, only garlic and tobacco showed significantly high antifungal activity against the test pathogen based on poisoned food technique. Garlic extract showed complete inhibition (100%) at 1/2 dilution and more than 94% growth inhibition at concentrations as low as 1/10 dilution after seven days of incubation. However, black pepper and turmeric extracts showed moderate inhibition (20-70%) whereas, no inhibition was recorded in 1/8 and 1/10 dilution of garden croton extract. Conclusion, significance and impact of study Our findings suggested that garlic extract is the most potential antifungal agent against Curvularia sp. and can be used as bio-fungicide thus would reduce the dependency on synthetic fungicides by farmers.

Aims: This work aimed to evaluate the antimicrobial activities of three different sources of wood vinegars obtained from pyrolysis of carambola (Averrhoa carambola), coconut shells (Cocos nucifera) and mango (Mangifera indica) and to identify their chemical composition. Methodology and results: Agar well diffusion technique was employed to assay the antifungal activity of the wood vinegars against Fusarium oxysporum, Colletotrichum gleosporoides, and Pestalotiopsis microspora and disc diffusion technique for antibacterial screening against Ralstonia solanacearum. The chemical compositions of these wood vinegars were also analyzed using GC-MS by employing the headspace technique. All wood vinegars exhibited antimicrobial activity against tested pathogens. Wood vinegar from carambola exhibited the most promising antimicrobial effect followed by coconut shells and mango. The GC-MS analysis revealed the wood vinegars from coconut shells, carambola, and mango are different in the chemical composition and active compounds. Major compounds identified in coconut shells are furfural, phenol, benzofuran, acetic acid, hexanal, ethanone, and formic acid. In carambola, the main compounds are furfural, imidazole, 3-pyridinecarboxaldehyde, benzaldehyde, phenol, benzofuran, indene, acetic acid, indazole, naphthalene, cyclohexanecarboxylic acid, palmitamide, palmitic acid, heptadecanenitril, and sterylamide. Meanwhile, the main chemical compounds in the pruning of mango-based vinegar consist of toluene, furfural, imidazole, annulene, benzaldehyde, phenol, carbamic acid, acetic acid, naphthalene, heptadecanenitril, and stearylamide. Conclusion, significance and impact of study It is suggested that wood vinegar from carambola, coconut shells, and mango is a promising antimicrobial agent in plant disease control, showing good potential for inhibition of selected plant pathogenic microorganisms.
Anti-Infective Agents ; Acetates