Control of Aculops lycopersici with the Predatory Mite Transeius montdorensis

SIMPLE SUMMARY: The tomato russet mite (TRM) is a significant problem in greenhouse tomato crops, and it has recently become more prevalent in Europe. The few acaricides available for its control are not specific and their effectiveness is limited. Several predatory mites have been tested for regulating TRM populations. Although these predators consumed most TRM stages in lab conditions, they were not able to freely move across the tomato plant due to the presence of glandular trichomes. TRM seeks refuge from predation precisely in the dense layer of glandular trichomes, in the upper part of the tomato plant. Consequently, most of predatory mites failed under crop conditions due to a lack of adaptation to the tomato plant. In this study, the predatory mite Transeius montdorensis has shown that it is adapted to the tomato plant since it was able to move through the trichome layer and prey upon TRM. When T. montdorensis was preventively released together with its breeding prey, it was able to greatly limit the growth of the TRM population in a tomato plot, and thus an increase of yield was observed. Therefore, T. montdorensis is a promising candidate for the control of TRM. ABSTRACT: In this study, the predatory mite Transeius montdorensis (Acari, Phytoseiidae) was tested for the control of the tomato russet mite (TRM) Aculops lycopersici (Acari, Eriophyidae) in experiments with small plants, under semi-field and crop conditions. The releasing strategy consisted of repeatedly introducing the predator together with additional breeding prey. The predator was able to move and disperse to the upper part of the tomato plant where the TRM seeks refuge. At the crop level, significant reductions in TRM populations were observed that resulted in a significantly higher yield compared to the conventional control plot, where pesticides were used to control the pest. Caution should be taken when extreme temperatures or humidity occur as they could be deleterious to the predator population. Hence, crop practices should include the management of environmental parameters in the greenhouse to ensure the success of this TRM-control strategy. In conclusion, this biological approach seems to be an effective measure to control the pest and should be further implemented at crop level.