Nanoemulsions in rice blast control: Biochemical and physiological mechanisms

Rice blast, caused by Magnaporthe oryzae (syn Pyricularia oryzae), remains one of the most destructive diseases of rice, resulting in severe yield losses in many rice-producing regions. Reliance on chemical fungicides has provided only partial and short-term relief, raising concerns over the development of resistance, environmental impacts, and food safety. In recent years, nanoemulsions (NEs) - fine oil-in-water or water-in-oil dispersions stabilized by surfactants - have gained attention as a practical and environmentally compatible alternative. This review consolidates recent advances in NE formulation, encompassing both high-energy and low-energy preparation techniques. Summarizes the key physicochemical parameters that influence stability and bioactivity. Special attention is given to plant-derived active compounds encapsulated in NEs, their modes of action against M. oryzae, and their performance in laboratory and field trials. The comparative advantages of NEs over conventional fungicides, their integration into rice blast management strategies, and the technical and regulatory hurdles to wider adoption are discussed. By linking efficacy with sustainability, nanoemulsion technology offers a promising route toward more resilient and eco-friendly crop protection systems.