**6. Conclusions**

HLB is one of the century-old diseases in the history of citrus pathology. The global spread of HLB disease causes economic loss in most citrus-producing countries. The causal agent of HLB, *Candidatus* Liberibacter, impedes understanding its pathogenic mechanism, fastidious nature, and unculturable in artificial conditions. Future research will focus on the isolation and pure culture of these proteobacteria. The rootstock and scion of some tolerant varieties have been noted and used by citrus growers in citriculture. These tolerant varieties have the potential to suppress the progression of HLB in Las-infected trees. The HLB management program recommends the intense psyllid control and removal of Las-infected trees in citrus groves. Citrus farmers focus on maintaining productivity in the HLB-affected trees by using plant defense activators, micronutrients, and fertilizers and paying more attention to water irrigation systems. Besides, thermotherapy is still an efficient methodology for eliminating and suppressing the causal agents in citrus scions and rootstock.
