Potential of Phyto Extracts and Essential Oils in Controlling of Leaf Blight Pathogen Alternaria alternata of Gerbera (Gerbera jamesonii L.): An In-vitro Approach

Abstract

Gerbera jamesonii L.is a commercially important ornamental crop, but its production is severely constrained by leaf blight caused by Alternaria alternata, leading to 40-60 % yield and quality losses. Increasing concerns over fungicide resistance and chemical residues necessitate sustainable, eco-friendly alternatives. The present investigation was undertaken to evaluate the in vitro antifungal efficacy of selected Phyto-extracts and Essential oils against Alternaria alternata. The poisoned food technique was used to assess the efficacy of six Phyto-extracts (nettle grass, vach, bitter melon, jatropha, turmeric, and garlic) at 5%, 10%, and 15% concentrations, and six essential oils (thyme, lemongrass, eucalyptus, tea tree, moringa, and ginger) at 200, 400, and 600 ppm. Among Phyto-extracts, garlic extract at 15% showed the highest inhibition of mycelial growth (74.22%), followed by turmeric (59.21%) and vach (51.70%). Among essential oils, thyme oil at 600 ppm exhibited the highest antifungal activity (93.42%), followed by tea tree (78.43%) and ginger oil (76.69%). The findings demonstrate the significant antifungal potential of garlic extract and thyme oil against A. alternata, supporting their use as plant-based biofungicides. This study provides a baseline for incorporating phyto-extracts and essential oils into integrated, eco- friendly disease management strategies for sustainable gerbera cultivation.