Citrus greening or “Yellow Dragon Disease” (Huanglongbing) is a disease of citrus plants caused by a vector-transmitted bacterium called Candidatus liberibacter. The infection is spread via the leaves of an infected plant spreading towards another plant. Bacteria colonize the veins in the tree roots and starve the trees of nutrients.
The infection leads to a yellowing (mottling) of the leaves of the infected plant. This leads to a loss of fruit quality, with the oranges that are borne being unsuitable for sale. After this, defoliation occurs and, eventually, the plant dies.
The economic consequences of the disease are huge. The citrus industry is valued at $10.7 billion citrus in the state alone. The new data is based on grower estimates, with agricultural workers reporting on ‘as found’ cases. The latest data has come from an analysis carried out by the University of Florida Institute of Food and Agricultural Sciences.
Some 200 growers provided information for the study, which represented around 31 percent of the orange acreage in the state. The loss of yield is just over 41 percent.
The fallout from this means:
$7.8 billion in revenue has been lost;
162,200 citrus acres have gone;
7,513 jobs have been cut.
These figures, pertaining to the effects of citrus greening, relate to the period 2007 to 2015.
The extent of the problem has led to the research conclusion: “Even though the industry acknowledges that greening has reached epidemic proportions across the state, estimates of the level of infection and its impact on citrus operations are scarce.”
These conclusions indicate that better measures are required to stem the rate of infection. One method being considered involves laser treatment of infected plants. Another potential method is heat therapy. An alternative could be breeding resistant trees, although this is a longer-term project.
