Climate plays a key role for the distribution and development of harmful organisms. Scenarios predicting future changes in the prevalence of pests and pathogens serve as a basis for planning adaptation measures in plant protection.
Climate change will affect the way harmful organisms exert pressure on crops. This requires changes in plant protection measures. Quantitative information on the development and distribution of pests and pathogens under future climatic conditions supports the adaptation process.
The goal of this research area is to develop scenarios concerning the distribution and development of harmful organisms of importance for Swiss agriculture, based on current climate scenarios and with the help of computer simulations. These scenarios factor in possible shifts in site suitability for the crops and the direct impacts of climate change on plant growth.
In this research area, scenarios concerning the spread and proliferation of harmful organisms are developed with the help of statistical and process-based models based on the new climate change scenarios for Switzerland. The models are calibrated on the basis of current data. The target area is extended to the whole of Europe for the study of invasive species. Corresponding data and climate change scenarios are taken into account.
The impacts of climate change on harmful organisms are discussed using the examples of the codling moth (Cydia pomonella), a domestic pest in fruit farming, and the brown marmorated stink bug (Halyomorpha halys), an invasive alien pest.
The effect of higher temperatures on the pace of development and the number of generations of the codling moth is analysed taking into account the temporal synchronicity between host plant and pest organism.
The distribution and seasonal prevalence of the brown marmorated stink bug is simulated under present and future climate conditions using a bioclimatic population model. The model makes it possible to take a closer look at the effect of extreme temperatures on the development of this insect pest.
- Because of global warming, the phenological development of insect pests begins earlier in the year and proceeds more quickly. In the case of codling moth, this promotes the development of additional generations, which potentially leads to an additional infestation in apple orchards. However, apple varieties that ripen early are less affected than apple varieties that ripen late.
- The example of the brown marmorated stink bug shows that heat stress during very hot summers can temporarily decimate the population of insect pests.
- In the long-term, cold stress is becomes less relevant for the survival of insects. Insect pests can thus hibernate better and establish themselves in Switzerland. Higher population densities are to be expected in spring.
- As can be clearly seen from the example of the brown marmorated stink bug, insect pests will be able to spread to higher altitudes in the future due to higher winter temperatures.
- Climate change fosters the spread of alien pests from south to north. Natural barriers to distribution, such as the Alps, will be less effective in the future.
- If efforts are undertaken to curb global warming, the magnitude of the impact of climate change on the spread and proliferation of harmful organisms will remain low in many cases until the end of the century.
As a founding member of NCCS, the Swiss Federal Office for Agriculture (FOAG) commissioned Agroscope and the Research Institute of Organic Agriculture (FiBL) to address this issue. The CABI in Delémont is also involved in the area of invasive, alien insect pests.
Last modification 09.09.2022