<em>In Vitro</em> antifungal activity of selected plant extracts against mango stem end rot pathogen: <em>Lasiodiplodia theobromae</em>

Abstract

Phytopathogens are primarily controlled through the application of synthetic products, which harm human and environmental health. The use of plant-derived extracts as ecofriendly bioagents has become increasingly popular due to the biologically active compounds present in the plants. Thus, a study was conducted to determine the antifungal activity of the ethanol and acetone leaf extracts of Argyreia pomacea, Coccinia grandis, Erythrina subumbrans, and Gymnema sylvestre against the causal pathogen of mango stem-end rot. Pathogen was isolated from diseased mangoes and identified as Lasiodiplodia theobromae. The pathogenicity of the isolated L. theobromae was confirmed on healthy samples of mangoes. The antifungal activity of leaf extracts was determined by the food poison technique. The leaf extracts were tested at different concentrations of 50, 25, and 12.5 mg/ml. Results indicated that the ethanol extract of E. subumbrans (29.21 ± 0.65 %) at the concentration of 50 mg/ml showed the highest percentage of mycelial growth inhibition followed by the acetone extract of G. sylvestre (28.97 ± 0.79 %) at the concentration of 25 mg/ml against the L. theobromae. The percentage of mycelial growth inhibition was significantly different among all treatments (P < 0.05). This might be due to the different kinds of phytochemicals in the plant leaves. Further studies are required to isolate and identify the specific bioactive compounds from the leaves, responsible for these antifungal activities.