Candidatus Liberibacter asiaticus is a bacterium that primarily affects citrus plants, causing a disease known as citrus greening or Huanglongbing (HLB). This pathogen is transmitted by the Asian citrus psyllid, a small insect that feeds on the sap of citrus trees. Infected trees often show symptoms like yellowing leaves, stunted growth, and misshapen fruit, leading to significant economic losses in the citrus industry. The bacterium is difficult to control because it resides in the phloem tissue of the plant, making it hard to treat with conventional methods. Management strategies focus on preventing the spread of the Asian citrus psyllid and removing infected trees to protect healthy ones.