Plant extracts for the management of Black Shank and Fusarium Wilt of Tobacco: A Comprehensive review

Tobacco (Nicotiana tabacum L.), a globally significant cash crop, is severely impacted by soil-borne diseases such as Black Shank (Phytophthora nicotianae) and Fusarium wilt (Fusarium oxysporum f. sp. nicotianae), leading to substantial yield losses. The increasing prevalence of fungicide-resistant strains and stringent regulations on synthetic pesticides have intensified the need for sustainable alternatives. Plant-derived extracts, containing bioactive compounds like curcumin, allicin, and thymol, have shown promising antifungal and plant immunity-enhancing properties, offering an eco-friendly solution with reduced resistance risks. However, their field application is hindered by inconsistent efficacy, rapid degradation, and formulation instability. Recent advancements in nanotechnology, particularly nano-encapsulation using chitosan-based nanoparticles and lipid carriers, have improved the stability, bioavailability, and controlled release of these extracts, enabling targeted delivery to infection sites. Through synergistic interactions, both plant extracts and biocontrol agents (Trichoderma, Pseudomonas) has suppressed disease. Despite these innovations, commercialization faces challenges such as regulatory hurdles, scalability constraints, and limited farmer adoption due to cost and awareness gaps. This review examines the current applications of plant extracts in managing Black Shank and Fusarium wilt, emphasizing advancements in nano-formulations and integrated biocontrol strategies. It also discusses key barriers to large-scale implementation and proposes actionable solutions, including standardized protocols, farmer education initiatives, and policy incentives. By integrating cutting-edge science with practical agricultural practices, plant extracts augmented by nanotechnology and genetic engineering can revolutionize sustainable disease management in tobacco cultivation, ensuring long-term crop protection and productivity