Simultaneous application of entomopathogenic Beauveria bassiana granules and predatory mites Stratiolaelaps scimitus for control of western flower thrips, Frankliniella occidentalis

Western flower thrips, F. occidentalis (Pergande) (Thysanoptera: Thripidae), is one of the most important pests of agricultural and horticultural crops worldwide. Adults and larvae injure plants through their feeding and virus transmission. However, suppression of the soil-dwelling pupal stages offers opportunities to minimize damage from the plant-feeding stages. Effects of a granular formulation of the entomopathogenic fungus B. bassiana GZGY-1-3, the predatory mite S. scimitus (Berlese) when applied to the soil individually and in combination for the management of F. occidentalis, were investigated on eggplant (Solanum melongena) under greenhouse conditions. The application of B. bassiana granules or predatory mites alone, or in combination, resulted in significant reductions in F. occidentalis populations compared with the untreated control. Compared with the untreated control, B. bassiana, S. scimitus and their combination resulted in declines of 59.41%, 72.59% and 86.03% for larvae and 53.62%, 66.11% and 82.18% for adults, respectively. The combined use of B. bassiana and S. scimitus improved control over the use of either biological control agent individually and helped assure more consistent management of F. occidentalis. Thus, we demonstrate the potential benefits of soil-dwelling predators and B. bassiana granules for management of F. occidentalis in protected crops.