General Information: Candidatus Liberibacter asiaticus causes Huanglongbing (also called citrus greening disease) in citrus in Asia. This organism causes a lethal infection to the tree and is transmitted from tree to tree by the sap-sucking Asian citrus psyllid, Diaphorina citri. Once infected the citrus tree turns yellow (huanglongbing means yellow dragon disease) and the fruit remains green.