Essential oils: A boon towards eco-friendly management of phytopathogenic fungi

Since the era of the beginning of the eco-friendly pest management, various plant-based products showed promising actions, and amidst them, essential oils obtained from the leaves, barks, stems and different parts of the plants proved to be a boon towards effective control of various phytopathogens. Essential oils are odoriferous, volatile organic compounds, consisting of a broad spectrum of secondary plant metabolites. Besides their antibacterial, insecticidal, antimicrobial activities, they have enormous potential to reduce the damage due to phytopathogenic fungus. In about 3000 essential oils identified, only 300 found to be economical, and a narrow spectrum of them has been used to manage fungi. As for as their mode of action is concerned, in fungal pathogens, essential oils establish a membrane potential across the cell wall and disrupt ATP assembly, cell walls and their permeability, leading to cell wall damage. Moreover, improvement in formulations like nano and microemulsions and stabilizing formulations has led to a new paradigm towards efficient control of plant pathogenic fungi. Therefore, the present review depicts the involvement of various plant essential oils in fungicidal and fungistatic activities for controlling plant diseases and also emphasizes on the modes of action of various essential oil products and their formulations available. It also reveals the constraints regarding the essential oil formulations which we have to eliminate for further betterment in eco-friendly phytopathogenic fungi management.