Modeling the potential impact of climate change on the distribution of Western Corn Rootworm in Europe

English. The Western Corn Rootworm (WCR), Diabrotica virgifera virgifera, is an important insect pest of corn, which has been introduced into Europe from Northern America in 1980s. Since then, its distributional range is continuously expanding over the Central and South-Eastern Europe. This study assessed the potential effect of increased temperatures on the timing of WCR generation development and on the WCR distributional range in 2011-2100. An impact model, describing a linear relationship between temperature and thermal requirements for the complete development of adult WCR, was forced by an ensemble of climate model data from three regional climate models, representing two different future forcing scenarios. The impact model simulations showed the fulfillment of temperature requirements in earlier date and over the extended area, covering continental Europe, large parts of British Isles and Scandinavia, in 2011-2100 in comparison with 1981-2005. In addition, the impact model projections display an increase in frequencies of years in which the temperature requirements of the WCR are fulfilled in central, eastern and northern parts of Europe, thereby indicating a future northward extension of area suitable for the establishment of a permanent WCR population. Policymakers are needed be informed about possible risks of the WCR spread in order to adjust pest management practices.

English. The climate system has been instrumentally observing since the mid-19th century, providing evidence of temperature increase. The process is very likely caused by an increase in anthropogenic emissions of greenhouse gases. A warmer climate may affect complex interaction, which exist between environment, insect pest and host plant. The possible responses of insect to climate change should be understood to develop relevant strategies in pest management. This study focuses on the Western Corn Rootworm (WCR), Diabrotica virgifera virgifera, an important insect pest of maize. It significantly reduces maize yield by damaging maize roots. Yield losses may reach up to 40%. The WCR has been introduced into Europe from Northern America in 1980s. Since then, the insect has been spread to large parts of Central and South-Eastern Europe. Temperature influences the development of insects, which happens within specific temperature ranges. Therefore, the data of future temperature, produced by climate models, can be used to analyse temperature suitability for insect in a particular geographical region. For this purpose a mathematical model describing the temperature requirements of the WCR has been developed. The model simulations showed that favorable temperature conditions for the development of adult insect may occur earlier it the year and over a larger area in 2011-2100 in comparison with present day. The progression is dependent on current and future emission of greenhouse gasses. The abovementioned area includes continental Europe, considerable parts of British Isles and Scandinavia. In addition, the percentage of years with appropriate temperatures may increase, allowing the WCR to migrate into the northern European regions and establish a permanent population. Interested parties are needed be informed about possible risks of the WCR spread to be able to adapt pest management practices, including crop rotation and monitoring of areas potentially suitable for the insect.