Origin
Candidatus Liberibacter asiaticus, Citrus greening is a plant disease transferred by a bacterium. It is transferred from plant to plant-primarily by piercing-sucking insects called psyllids. Dodder, a parasitic plant, has also been shown to transmit the bacterium, but this rarely occurs in nurseries, groves, or homeowner yards. Pruning and other mechanical transmission methods do not appear to be important in transmission, but human movement of host material contributes to the spread of the vector and the disease.

Life Cycle
The bacterium, vectored by an insect called a psyllid, is named Candidatus Liberibacter asiaticus. The Candidatus part of the bacterium's name indicates that it cannot be cultured. Two other related forms of the disease are known, of African, and South American origin; both are also vectored by the Citrus Psyllid. The bacterium is carried by the psyllid from host plant to host plant, where it resides exclusively in the phloem tissues. As the bacterium multiplies, it chokes off the supply of nutrients moving throughout the plant, weakening the plant and eventually killing it.

Distribution
Generally, samples are collected from new flushes of tip growth, and the veins and petioles are cut from the leaves and processed to maximize the chance of finding the bacterium. As of June 2008, the disease has been confirmed in 30 counties in Florida and a single parish in Louisiana.

Control Efforts
Chemical management tools are not utilized for controlling the disease, but insecticides are used in nurseries and groves to manage the vector population. Current efforts are underway to quarantine movement within and out of Florida, and to eradicate the disease in Louisiana.

Reference
Bugwood Wiki

Selected Images

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Invasive Listing Sources

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• South Carolina Plant Pest List

References

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Common Name Reference: Web Search - http://spdn.ifas.ufl.edu/Citrus%20_Greening.htm
Scientific Name Reference: Web Search - http://spdn.ifas.ufl.edu/Citrus%20_Greening.htm