Citrus greening disease

Citrus greening disease
Citrus greening disease on mandarin oranges
Common namesHLB, citrus vein phloem degeneration (CVPD), citrus greening disease, yellow shoot disease, yellow dragon disease, leaf mottle yellows in the Philippines, citrus dieback in India
Causal agentsLiberibacter spp. (L. asiaticus, L. africanus, L. americanus)
Hostscitrus trees
VectorsDiaphorina citri, Trioza erytreae
EPPO Code1LIBEG
DistributionAsia, Africa, United States

Citrus greening disease (Chinese: 黃龍病; pinyin: huánglóngbìng abbr. HLB) is a disease of citrus trees caused by bacteria of the genus Liberibacter. These microbes are transmitted by two species of bug: the Asian citrus psyllid Diaphorina citri and the African citrus psyllid Trioza erytreae. It has no known cure. It is graft-transmissible.

There are three different types of the disease: a heat-tolerant Asian form, and the heat-sensitive African and American forms. It was first described and reported in southern China in 1919. The African variation was first reported in 1937 in South Africa, where it is still widespread. It reached Florida in 2005, and within three years had spread to the majority of citrus farms. The rapid increase in this disease has threatened the citrus industry in the entire US. As of 2009, 33 countries had reported the infection in their citrus crop.