The confirmed role of Tomato Russet Mite (TRM), Aculops lycopersici (Trombidiformes: Eriophyoidea), as a biological vector for Tomato Fruit Blotch Virus – ToFBV (Blunervirus solani) belonging to kitaviridae family — marks a paradigm shift in its phytosanitary importance. Evidence shows TRM successfully acquires and transmits ToFBV across various phenological stages. Recent insights into ToFBV epidemiology, including precise tissue localization and the exclusion of vertical seed transmission, underscore the mite vector’s indispensable role in viral dispersal. The potential for other solanaceous species to serve as reservoirs is currently under investigation and is crucial for understanding how specialized agricultural strains transition to alternative hosts, ultimately contributing to the development of more effective cross-crop management and forecasting strategies. This study evaluates the reproductive fitness of a TRM population adapted to tomato, quantified through the population growth rate (r) across a selection of diverse host plant species by reflecting the mean growth performance, under controlled laboratory conditions, serving as an indicator of the pest’s host-shifting potential and invasive capacity. Our findings revealed that tomato-adapted TRM populations exhibit varied fitness across the Solanaceae family (Solanum nigrum, Convolvulus arvensis, Capsicum annuum, Nicotiana tabacum, and Petunia spp.), all supporting positive growth. Reciprocal transfer experiments further highlighted host-specific adaptation, confirming the mite’s high ecological plasticity. Black nightshade (Solanum nigrum) is a critical alternative host and ubiquitous weed that serves as a significant reservoir for both the mite and the virus. Notably, S. nigrum proved as suitable as tomato, facilitating robust fecundity and a female-biased sex ratio. Managing these wild hosts is essential for refining Integrated Pest Management (IPM) strategies to prevent rapid recolonization and sustained inoculum pressure. Our findings identify S. nigrum as the primary «green bridge» for overwintering and re-infestation. While taxonomically distant species like field bindweed and white goosefoot show lower suitability, they may sustain residual populations under favorable conditions. Effective IPM must prioritize the eradication of these weed reservoirs. Given limited varietal resistance, developing resistant germplasm is a research priority to mitigate the global economic risks posed by the TRM–ToFBV complex.