Geothermal tomato is a very important agricultural development axis in southern Tunisia. The tomato russet mite, Aculops lycopersici (Tryon), is a major pest that attacks tomato crops in heated greenhouses, causing economic losses. The present study focused on monitoring the spread of A. lycopersici between March and June in a heated tomato greenhouse and testing the pathogenicity of two strains of the entomopathogenic fungus Beauvaria bassiana R444 and ATCC in comparison with sulfur, oxygen peroxide, and abamectin. The wind has been shown to spread these mites inside the greenhouse. The mites then spread along the stem of the plant, depending on the number of infected leaves and tomato bunches. The rate of propagation on the stem is linked in the upward direction following the application of the leaf removal technique, which is positively correlated. Treatments with B. bassiana against mobile forms of A. lycopersici showed reduction rates between 77.57% and 95.45% after 10 days of treatment. Similarly, the other treatments showed efficacy, with significant percentages of reduction of mobile forms equal to 82.19%, 87.58%, and 44.26% for abamectin, oxygen peroxide, and sulfur, respectively. In conclusion, entomopathogenic fungi have proven to be highly effective in reducing A. lycopersici populations. These microbiological agents can be considered valuable resources in the fight against this pest, helping to minimize its impact on the ecosystem.