Global climate suitability of citrus huanglongbing and its vector, the Asian citrus psyllid, using two correlative species distribution modeling approaches, with emphasis on the USA

Two approaches to correlative species distribution models (MaxEnt and Multi-Model Framework) were used to predict global and local potential distribution of huanglongbing (HLB) caused by Candidatus Liberibacter asiaticus (CLas) and its vector the Asian citrus psyllid (ACP, Diaphorina citri Kuwayama). Long-term climate data were sourced from the Worldclim website. The global distribution of CLas and ACP was gathered from online databases, literature review and communication with specialists. Data on Clas and ACP distribution in the USA were not used in model calibration to allow model validation for independent locations. Both models successfully predicted Florida and coastal areas in the Gulf Coast states as highly suitable for Clas and ACP. The models also predicted that coastal areas in California were climatologically favorable for ACP and Clas, but less so than in Florida. When current USA presence data were included in the models, the suitable areas for ACP establishment expanded to the Central Valley, CA, while this area remained less conducive for CLas. Climate suitability was primarily related to rainfall and secondarily to temperature. Globally, both models predicted that climates in large areas of Africa, Latin America and North Australia were highly suitable for ACP and CLas, while the climate in the Mediterranean area was moderately suitable for ACP but less suitable for CLas, except for that in southern Portugal and Spain. Clas predictions from our models could be informative for countries like Australia, New Zealand, citrus-producing European countries and much of Africa, where CLas and D. citri have not been reported.