Huanglongbing (HLB) is presumably caused by the phloem-limited bacteria, Candidatus Liberibacter asiaticus (CLas), and is one of the most devastating diseases of citrus. A distinctive chlorotic mottle on fully expanded leaves is one of the identifying symptoms of HLB.
Click here for original story, Nutrient uptake in citrus rootstock affected by huanglongbing
Source: Phys.org