Single and combined releases of biological control agents against canopy- and soil-dwelling stages of Frankliniella occidentalis in cyclamen

Frankliniella occidentalis is a major pest in agriculture. Problems with its control are mainly due to pupation in the soil and resistance to insecticides. Biological control agents (BCA) can be used against thrips pests as an alternative to conventional insecticides. We evaluated the effectiveness of a number of BCA for control of F. occidentalis in cyclamen under greenhouse conditions. Three BCA (Amblyseius swirskii, Neoseiulus californicus and Orius laevigatus) were applied to the canopy and two (Macrocheles robustulus and Steinernema feltiae) to the soil in single and combined releases. Results showed that applications of predatory mites and nematodes achieved good control of F. occidentalis. Unsatisfactory control was obtained using O. laevigatus. The use of nematodes determined the extinction of thrips, but with a delay. The combination of nematodes in the soil and predatory mites in the canopy caused a more prompt reduction of thrips in flowers.