Exploring the climate suitability of Slovenia for the invasive species Spodoptera frugiperda (JE Smith)

In the context of climate change and globalisation, the risks for invasive species are increasing. One example of this is Spodoptera frugiperda (JE Smith), commonly known as the fall armyworm (FAW). The FAW originates from the tropical and subtropical regions of America and has spread to most continents worldwide in recent years. Since the FAW has recently also spread to the Mediterranean regions of Europe, the aim of this study was to analyse the potential susceptibility of Slovenian agriculture to this pest, with specific emphasis on maize (Zea mais). Additionally, the climate suitability was assessed for four possible natural enemies of FAW. The climate suitability of the past and future climate in Slovenia was evaluated in relation to the latest available data on the global occurrence of FAW and its natural enemies. The analysis was carried out on the basis of historical data and climate model projections for temperature and precipitation. The climate projections included 6 sets of regionally downscaled model results from the EURO-CORDEX project for the RCP4.5 and RCP8.5 scenarios. The results show that an increasing probability of FAW occurrence in Slovenia throughout the 21st century, especially in the maize-growing areas of Slovenia with the largest areas under maize cultivation. The natural enemies whose climatological niches were calculated to be the most comparable to those of the FAW are parasiotids Telenomus remus and Trichogramma Pretiosum. The results of this study can serve as a tool for the possibilities of pre-emptive introduction of natural enemies of FAW to Slovenia, which is a method of biological pest control, in which the use of synthetic pesticides is replaced by the introduction and release of natural enemies of the pests.