Estimating the impact of climate change on the occurrence of selected pests in the Central European region

The intensity and area of occurrence of pest species are strongly determined by the overall climate conditions of a locality and the weather pattern within a given season in combination with other factors (e.g. host plant abundance). While inter-seasonal weather variability and consequent fluctuations of individual pest species are well-known phenomena, changes in overall climate conditions and associated range shifts of particular species have likewise become important areas of research, especially during the last decade. The present study demonstrates the methodology and benefits of climate-driven modelling tools using the European corn borer (ECB) Ostrinia nubilalis (Hbner, 1796) and Colorado potato beetle (CPB) Leptinotarsa decemlineata (Say, 1824) as examples. CLIMEX models of the potential geographical distributions of each species were created and validated under present climate conditions. Both models were then used to study the effects of climate change on ECB and CPB by estimating changes in population dynamics and/or infestation pressure during the first half of the 21st century. Simulations were conducted using 3 global circulation models (HadCM3, NCAR-PCM, and ECHAM4) and scaled by low and high values of global temperature change. The results predict an increase in newly established areas and in the number of pest generations per year. The ratio of arable land affected by a particular number of generations is also expected to increase. Under the HadCM3-high 2050 scenario, this ratio increases by about 43 and 48% for the second generations of CPB and ECB, respectively. Another significant result is shown for higher altitudes currently unoccupied by pests. We recorded rapid generation increase (from 0 to 2), which supports the hypothesis that these areas are more affected by increased temperatures.