Modelling the potential distribution of the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae) using CLIMEX

One invasive species that decreases citrus fruit yield is the Asian citrus psyllid, Diaphorina citri Kuwayama. The psyllids are the carriers of Candidatus Liberibacter species, the pathogen that causes citrus greening disease (commonly called huanglongbing, or HLB), which is the most devastating citrus disease in the world. Originally from Southeast Asia, the Asian citrus psyllid, a highly invasive species, is spreading rapidly throughout the world. Regarding geographical distribution and population growth, climate change will aggravate its impacts on many citrus agroecosystems. However, limited information on the mechanisms underpinning the pest's invasion impedes the formulation of biosecurity risk measures. We highlight the potential suitable areas for D. citri, combining their climatic requirements, temperature and humidity, in the CLIMEX model. The model's performance was high, and it can be utilized for biosecurity risk assessment, as only 2.82% of the 496 known occurrence spots were located in areas deemed unsuitable by the model's fit. The potential habitat suitability for D. citri covered all continents except Antarctica, and the suitability ranges from unsuitable (EI < 0) to highly suitable areas (EI >= 30). Our model predicted suitable areas outside its known native and invaded regions, especially in Africa, South America, and Oceania. Most of these regions will remain suitable for D. citri in the future. This underscores the importance of our findings as a significant guide for future early detection and the development of climate-smart management strategies against D. citri.