Citrus Greening (Huanglongbing)
Candidatus Liberibacter asiaticus
Overview
The most devastating disease of citrus worldwide, spread by the Asian citrus psyllid. Infected trees produce bitter, misshapen, partially green fruit and eventually decline and die.
Symptoms
Asymmetric blotchy mottling of leaves (unlike nutrient deficiency which is symmetric). Lopsided, bitter, partially green fruit with aborted seeds. Twig dieback. Stunted growth. Gradual decline over several years.
Environmental Conditions
Hot
Prevention
Control Asian citrus psyllid vector. Use certified disease-free nursery stock. Remove infected trees promptly. Apply systemic insecticides to protect healthy trees. Plant in screened enclosures where feasible.
Management
No cure available. Remove and destroy infected trees. Aggressive psyllid control on remaining trees. Nutritional programs may extend tree productivity. Research into resistant varieties and treatments ongoing.