HLB stands for Huanglongbing, a devastating bacterial disease affecting citrus trees. Also known as citrus greening disease, it is considered one of the most destructive diseases of citrus worldwide. The disease is caused by the Gram-negative bacterium Candidatus Liberibacter spp. and does not have any known cure.
Citrus greening disease HLB affects all citrus cultivars and species, causing symptoms including mottled, yellowing leaves, uneven fruit coloration, and stunted growth. Infected trees produce small, misshapen, and bitter fruits that are often green even when they should be ripe. Additionally, HLB weakens the plant, leading to premature fruit drop, reduced yield, and eventual tree death.
The bacterium Candidatus Liberibacter spp. is primarily transmitted via the Asian citrus psyllid insect vector. When the psyllid feeds on infected plants, it can acquire the bacteria and spread it to healthy trees during subsequent feeding. Natural routes of transmission can also occur through the grafting of infected budwood or the use of contaminated tools in horticultural practices.
HLB poses significant economic threats to the citrus industry, as it has caused billions of dollars in losses globally. Management strategies involve early detection and removal of infected trees, control of the psyllid vector through insecticides and biological control, utilization of certified disease-free nursery stock, and plant improvement through breeding for resistance.
Efforts are continuously underway to develop effective treatments and strategies to mitigate the impact of HLB on citrus production and to prevent its further spread to new regions.
