Citrus greening disease

Article By:

Pelz-Stelinski, Kirsten S. Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, Florida.

Last reviewed:December 2019

DOI:https://doi.org/10.1036/1097-8542.138350

A devastating bacterial infection of citrus trees, also known as huanglongbing or yellow dragon disease, transmitted by psyllids (jumping plant lice). Citrus greening disease, which was first reported in Asia during the late 1800s, is the most economically important disease of citrus worldwide. The disease is also called huanglongbing (HLB), or yellow dragon disease, because of the appearance of yellow shoots on infected trees. It is endemic throughout Asia and Africa and has spread more recently to citrus-growing areas of the Americas. Three bacteria are associated with citrus greening disease: Candidatus Liberibacter asiaticus (present in Asia, North America and Brazil), C. L. americanus (present in Brazil) and C. L. africanus (present in Africa). The pathogens are vector-borne, fastidious (uncultured), phloem-limited, gram-negative alphaproteobacteria. Candidatus Liberibacter asiaticus (Las) is the primary bacterium associated with HLB. Following its initial discovery in Florida in August 2005, the incidence of HLB has reached nearly 100% in Florida citrus groves and has resulted in the loss of more than 60,000 commercial citrus acres and $1.3 billion (U.S. dollars). Within the United States, the disease is also found in Texas, California, Louisiana, South Carolina and Georgia. Currently, there is no cure for citrus greening disease. See also: Agricultural science (plant); Bacteria; Bacteriology; Fruit; Fruit, tree; Grapefruit; Horticultural crops; Invasion ecology; Lemon; Lime (botany); Orange; Pathogen; Plant pathology

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