Journal of Experimental Agriculture International

Fungal diseases can reduce the productivity and value of bamboo and other plant resources, creating interest in plant-derived antifungal agents as alternatives to synthetic fungicides. This study evaluated the in vitro antifungal activity of methanolic leaf extracts of Alangium chinense, Justicia gendarussa, Brugmansia suaveolens, Lantana camara, and Calotropis procera against Curvularia soli associated with bamboo leaf spot. Leaf extracts were prepared by Soxhlet extraction with methanol and incorporated into potato dextrose agar at 0.25, 0.50, 0.75, 1.00, 1.50, and 2.00%. Antifungal activity was assessed using the poisoned food technique, with mycelial growth and percentage inhibition measured after incubation at 25 ± 1 °C for 12 days. Thirty-six treatment combinations, each with three replications, were analysed using one-way ANOVA followed by Tukey's HSD test. All five botanical extracts reduced mycelial growth in a concentration-dependent manner. Alangium chinense was the most effective, producing 99.48% inhibition at 0.50% and complete inhibition from 0.75% onwards. Justicia gendarussa and Calotropis procera also achieved complete inhibition at 0.75%, while Lantana camara and Brugmansia suaveolens required 1.00% and 1.50%, respectively, for complete suppression. Overall treatment effects were significant for both mycelial growth and inhibition (p < 0.001). These findings indicate that the tested methanolic plant extracts, particularly Alangium chinense, warrant further greenhouse, field, phytochemical, and phytotoxicity evaluation before practical application.