A perspective of citrus Huanglongbing in the context of the Mediterranean Basin

Abstract

Huanglongbing (HLB) is one of the most catastrophic citrus diseases. HLB pathogens Candidatus Liberibacter asiaticus (Las), Ca. L. africanus (Laf), and Ca. L. americanus (Lam) and their insect vectors Asian citrus psyllids (ACP, Diaphorina citri) and African citrus psyllids (AfCP, Trioza erytreae) are invading citrus producing regions where HLB was absent previously, including the Mediterranean basin. Importantly, the Mediterranean region is one of the two major citrus producing areas without HLB. Here, I provide a short perspective regarding a) information related to the distribution of the HLB pathogens and psyllid vectors in this region and neighboring countries, b) predicted distribution of the HLB for this region, c) the possible evolution of Liberibacters and how they could have established their relationship with different hosts, and d) approaches to fend off HLB. Specifically, I emphasized the following measurements: quarantine measures against AfCP, ACP, Las, Laf, and Lam, early detection and diagnosis of HLB and removal of inoculum, surveillance of AfCP and ACP and eradication of citrus psyllids once identified.