Abstract: In recent years, Aculops lycopersici (Tryon, 1917) (Acari: Eriophyoidea) has occurred more frequently in tomato cultivation throughout Germany. If infestation of tomato greenhouses occurs A. lycopersici can cause devastating damage. At present, there are no biological control agents available that show satisfying results when used against A. lycopersici on tomato and also there are only a few acaricides available against this mite. In order to investigate plant protection agents which potentially could be used against A. lycopersici in tomato, a greenhouse trial will be conducted between May and August 2017. In this trial the acaricide “Vertimec Pro” (Abamectin, Syngenta), “PREV-AM” (orange oil, OroAgri) and the entomopathogenic fungus Beauveria bassiana formulated as “Naturalis” (e-nema) will be compared in their efficacy against A. lycopersici on tomato. After inoculation with A. lycopersici the population densities and the symptoms caused by A. lycopersici on tomato plants will be monitored frequently throughout the whole experiment. This will allow assessment of the direct and lasting effects of all three plant protection agents.