Comparative study of two predatory mites Amblyseius swirskii Athias-Henriot and Transeius montdorensis (Schicha) by predator-prey models for improving biological control of greenhouse cucumber

Suppression of the whitefly Bemisia tabaci (Gennadius) and the thrips Frankliniella occidentalis (Pergande) by the predatory mite Amblyseius swirskii Athias-Henriot on greenhouse cucumbers can be considerably affected by cooler conditions in winter. In this study, this well known mite was tested simultaneously with a more recent predatory mite Transeius montdorensis (Schicha), to find out which of them was better at controlling pests on cucumbers in winter in Mediterranean greenhouses. We developed a mathematical predator-prey model which involved releasing both predators with populations of the two naturally occurring pests in a greenhouse cucumber trial. T. montdorensis provided pest control that was similar to and as effective as that by A. swirskii. T. montdorensis exhibited higher populations than A. swirskii, specifically when climatic conditions were colder. However, as the weather became warmer, the A. swirskii population increased quickly. Therefore, releasing T. montdorensis in winter, followed with releases of A. swirskii in spring, may be a good pest control strategy for greenhouse cucumbers.