Biological control of the cherry fruit fly, Rhagoletis cerasi L. (Diptera, Tephriti- dae) by use of entomopathogenic nematodes: first experiences towards practi- cal implementation. Erste Erfahrungen bei der Anwendung entomopathogener Nematoden zur biologi- schen Bekämpfung der Kirschfruchtfliege in der Praxis

The use of entomopathogenic nematodes (EPN) is a promising approach to control the cherry fruit fly, Rhagoletis cerasi L.. We already demonstrated the high potential of EPN to infect larvae after leaving the cherry for pupation in the soil in laboratory and field experiments. For practice, an application technique is needed, that is both, growerand EPN friendly. We tested a tractor mounted spray boom for treatment under the canopy area. The achieved rate of EPN in the soil met the expectations. The activity of EPN in soil samples was high after application, but dropped to 60% of the initial activity within one week. Exact forecasting of larval drop from cherries is another major challenge. To obtain basic data, we recorded the phenology of infestation and larval emergence on trees which were not harvested. Sequential infestation on the same cherry variety was observed and larvae dropped from individual trees for several weeks.