Ensemble-based analysis of regional climate change effects on the pod midge (Dasineura brassicae Winn.) in oilseed rape

Abstract: The impact of regional climate change on the migration of the brassica pod midge (Dasineura brassicae Winn.) on crops of winter oilseed rape (Brassica napus L.) in the Grand Duchy of Luxembourg was evaluated for the past and projected future time-spans. A threshold-based statistical model for the first and the peak appearance of D. brassicae to oilseed rape crops was taken from the literature and combined with selected regional climate change projections of the EU ENSEMBLES project. An ensemble of six regional climate change projections was used to quantify the bandwidths of possible change signals and also to assess the uncertainty associated with these projections. In comparison to the reference period (1961-1990), the onset of the first appearance period was projected to occur between 4.3 (near future, 2021-2050) and 5.3 days (far future, 2069-2098) earlier per decade. Furthermore, the possible time-span of the first migration was prolonged from 20 days (near future) to up to 60 days (far future). The peak appearance period of the pod midge to the field will start significantly earlier (5 days per decade) under future climate conditions. Additionally, the time-span of possible migration will be prolonged from 9 days (near future) to up to 13 days (far future) under projected future climate conditions in comparison to the reference period.