Fusarium oxysporum f.sp. lycopersici (FOL) wilt endangers Egyptian tomato productivity. Nanotechnology has emerged as an efficient tool for managing plant diseases. This study evaluated salicylic acid nanoparticles (SA-NPs) and glycyrrhizic acid ammonium salt nanoparticles (GAS-NPs) against F. oxysporum in vitro. SA-NPs reduced F. oxysporum growth by 37.8%, and GAS-NPs by 18.9% at 3 ml/L, while SA-NPs at high doses significantly reduced the bacterial count in the tomato rhizosphere. Under greenhouse conditions, high doses of SA-NPs suppressed disease by 73%, compared to 87-93% for other treatments, coinciding with a significant decrease in the overall bacterial count in the tomato rhizosphere. A high dose of SA-NPs reduced heterotrophic, copiotrophic, and fluorescent pseudomonads in the tomato rhizosphere but did not affect the total number of fungi. In vitro, a high dose of both nanoparticles …