Abstract: The invasive Spotted Wing Drosophila (SWD), Drosophila suzukii, is infesting and damaging stone and berry fruits and causing huge economical losses since 5 years in Germany. Population development and infestation level vary between different years, hence regulation measures are difficult to place in an optimal way. To develop a decision support system (DSS “SIMKEF”) for control measures, different factors influencing population development, activity and infestation of fruit crops were analysed in a collaboration project for fruit crops (stone fruits and berries) and grapes. The DSS is expected to predict the population dynamics of D. suzukii and the actual pest infestation risk for the different crops. For this reason, the interaction of the entire life cycle and activity of D. suzukii with the most important meteorological factors, like temperature and relative humidity as well as landscape structures, wood, hedges or fields is described or functionally determined. Laboratory tests, monitoring results and already published data will be combined within the DSS. In this paper first focus is on the influence of cold and freezing temperatures during winter and landscape structure on population development. Second focus is on the influence of temperature and relative humidity as well as ontogenesis of host fruits on oviposition. As a first output of the DSS cherries will be assessed for their susceptibility depending on abiotic and ontogenetic factors.