In-vitro efficacy of different essential oils against Sclerotium rolfsii (Sacc.)

Abstract

This experimental study evaluated the effectiveness of different essential oils against the in vitro growth of Sclerotium rolfsii. The experiment employed a completely randomized design (CRD) with three concentrations (500, 1000, and 1500 ppm) of each essential oil, including thyme oil (Thymus vulgaris L.), cinnamon oil (Cinnamomum zeylanicum Blume), juniper oil (Juniperus horizontalis L.), neem oil (Azadirachta indica A. Juss.), lemon grass oil (Cymbopogon citratus (DC.) Stapf), peppermint oil (Mentha piperita L.), and an unamended control medium. This setup aimed to evaluate their efficacy against the mycelial growth of S. rolfsii. The data were analyzed using R software in R-Studio, and means were compared using Duncan’s Multiple Range Test (DMRT) at a 5% level of significance. Mycelium growth data were recorded at 24 hours, 48 hours, and 72 hours of incubation. All tested essential oils significantly inhibited the mycelial growth of the pathogen compared to the control (p<0.05). After 72 hours, thyme oil at all concentrations and lemongrass oil at 1500 ppm both achieved 100% growth inhibition. In contrast, neem oil at 500 and 1000 ppm showed the lowest inhibitory effects, with rates of 27.56% and 34.62%, respectively. Lemongrass oil at 500 ppm (75.39%) showed statistical similarity to cinnamon oil at 1000 ppm (79.12%). Peppermint oil at 1500 ppm resulted in 82.73% inhibition, and cinnamon oil at 1000 ppm (75.73%) showed comparable results to peppermint oil at 1000 ppm. Thus, the study highlights the superior performance of thyme oil among the tested essential oils. These effective essential oils can potentially be used at lower concentrations to minimize potential hazards. However, further research and field trials are essential to validate these findings for practical applications.