Effect of Botanicals Extracts on Phytopathogenic Fungi

Abstract

Phytopathogenic fungi are important causes of crop diseases and can substantially reduce plant growth, yield and quality. Although synthetic fungicides remain important tools for disease management, their repeated use has raised concerns related to environmental contamination, residues, resistance development and effects on non-target organisms. Plant-derived extracts and their bioactive compounds have therefore attracted considerable attention as potential components of sustainable disease management. The present review examines the antifungal potential of selected plant extracts against phytopathogenic fungi, with particular emphasis on neem (Azadirachta indica), garlic (Allium sativum), ginger (Zingiber officinale), cumin (Cuminum cyminum) and other botanicals. In present studies indicate that plant extracts can inhibit fungal mycelial growth, spore germination and other stages of fungal development, although their effectiveness depends on plant species, plant part, extraction solvent, concentration and target pathogen. Neem extracts, for example, have demonstrated inhibitory effects against Alternaria solani, Fusarium oxysporum, Rhizoctonia solani and Sclerotinia sclerotiorum. Plant secondary metabolites such as phenolics, flavonoids, terpenoids, alkaloids, sulfur-containing compounds and essential-oil constituents are considered important contributors to antifungal activity. Plant extracts may therefore provide useful alternatives or complements to conventional fungicides, particularly within integrated disease-management systems. However, standardization, formulation, stability, phytotoxicity, field efficacy and regulatory requirements remain important challenges.