Antifungal activity of selected plant extracts against Curvularia sp. infecting local purple sweet potato (Ipomoea batatas)

ABSTRACT

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.