Optimization of hoverfly application for biological control in horticulture : in open field production

Sammanfattning

Aphidophagous hoverflies can be used for biocontrol in greenhouses, but application in open field or high tunnels face the challenge of escaping hoverflies due do their natural migration behaviour. In this study, our goal was to develop a system to increase their loyalty to the release area. Providing enough resources could be the solution to suppress fly migration. Banker plants with alternative oviposition sites were placed in raspberry production tunnels and adult Eupeodes corollae Fabricius (Diptera: Syrphidae) were released on the same day or one day hereafter. The study was conducted at two raspberry (Rubus idaeus L.) farms in different parts of Sweden, one site in Scania and the other further north in Uppland. We saw a significant effect of the banker plant system; higher numbers of adults were observed in the banker plant treatment blocks than in controls. Oviposition rate was high and larval development was observed. The result shows that the banker plant system works to increase site loyalty and oviposition of hoverflies, but more research is needed for further optimization of the system.