Ecological models predict narrow potential distribution for Trioza erytreae, vector of the citrus greening disease

The African citrus psyllid, Trioza erytreae (Hemiptera: Triozidae), is a vector of citrus greening disease (Huanglonbing - HLB) caused by the bacterium Candidatus liberibacter. Native from Africa, T. erytreae was detected in northwestern Spain in 2014, and since then it has established along Atlantic coastal areas of the Iberian Peninsula. Given the severe bio-economic impact of HLB, an accurate assessment of the risk of potential spread of African citrus psyllid to citrus-growing regions of the Mediterranean area and the rest of the world, is urgently needed to design effective control strategies and anticipate economic losses. Therefore, I calibrated species distribution models to understand the bioclimatic characteristics that shape the distribution of T. erytreae and to assess the climatic suitability of the world’s major citrus-growing regions for this species under current and future climate conditions. The models identify mild summer and winter temperatures and high levels of precipitation as optimal conditions for long-term psyllid establishment. It is noteworthy that the models trained without the available occurrences in continental Europe, predict only the Atlantic coastal regions of the Iberian Peninsula as highly climatically suitable in Europe, which corresponds perfectly with the area currently invaded by the psyllid. This striking predictive accuracy lends great credibility to the model predictions. Most economically important citrus production areas in the world are predicted to be of low or moderate climatic suitability for T. erytreae. This research is crucial for assessing the global risk of HLB and is particularly timely for Europe where the African citrus psyllid has recently been detected.