Effects of climate change on pest-parasitoid dynamics: Development of a simulation model and first results

The influence of predicted climatic change on agricultural pest and beneficial insect species is of high importance for growers since increasing temperatures may have a direct impact on the developmental rates of insect populations. These parameters are species-specific and result in variable reactions to climate change, potentially disrupting the synchrony of pest-parasitoid dynamics. This study investigatedthe effect of increasing temperatures caused by climatechange on the population dynamics of the mealy cabbage aphid Brevicoryne brassicae , a worldwide occurring pest species in cruciferous crops, and the endoparasitoid Diaeretiella rapae . For three vegetable growing regions in lower Saxony, the population development of both species was simulatedfor (1) the near future (2041-2050), (2) the far future (2090-2099) and (3) the reference time period (1991-2000), using an age structured simulation model including simulated temperature data. An earlier first occurrence of D. rapae in spring compared to B. brassicae was shown, however with no disruption of the synchrony between the two populations. Despite the earlier occurrence and increased population size of D. rapae in future periods, B. brassicae maximum population size also increased. Furthermore, an earlier occurrence of alate aphids during the season resulted from the model, indicating a potential need to adapt pest management