The challenge of controlling the tomato russet mite (Aculops lycopersici) in tomato greenhouse productions

Abstract: Tomato russet mite [Aculops lycopersici (Massee, 1937)] (Acari: Eriophyidae) is
considered a common pest of several Solanaceae crops worldwide. In recent years, increasing
temperatures and the lack of effective management strategies have intensified pest pressure in the open field and in the greenhouse tomato cultivation in Slovenia. Since there is no available control measure against this pest in Slovenia, based on acaricide sprays, researchers tend to be more engaged in developing alternative control strategies. During the years 2022 and 2023 we tested various active ingredients, including sulphur and orange oil, as well as the entomopathogenic fungus Beauveria bassiana strain ATCC 74040. The efficiency of acaricides containing hexythiazox, which is authorised for the control of the Two-spotted spider mite, Tetranychus urticae Koch, was also tested. Spraying experiments were performed in the tomato greenhouse production area in Slovene Istria (the northern part of the Istrian peninsula). In both years repeated treatments with sulphur significantly reduced the eriophyid mite infestations on tomato. The efficiency of sulphur treatments in 2022 and 2023 reached 75.0 % and 87.5 %, respectively. The other products used in the experiments had no significant effect in reducing the mite population, and the efficacy of the treatments did not differ from the untreated controls. The overall success of Tomato russet mite control was closely related to weather conditions. High temperatures and heat stress in the year 2022 notable decreased the efficacy of treatments against eriophyid mites.