Citrus greening is one of the most serious diseases of citrus worldwide. There are three strains that are commonly associated with it. The Asian strain was found in Florida in 2005. This disease also has been referred to as Huanglongbing or yellow dragon disease. Citrus greening is spread (vectored) by the Asian citrus psyllid, Diaphorina citri, a recently introduced pest which is now found in Alabama, California, Florida, Georgia, Guam, Hawaii, Louisiana, Missisippi, Puerto Rico, Texas and the Virgin Islands.
The widespread distribution of citrus and the citrus psyllid pose a major threat to the U.S. citrus industry. At present, there is no effective control for the disease other than removing infected trees. Infected trees cannot be cured. They generally die within three years of becoming infected. The bitter-tasting, misshapen and underdeveloped fruit is unmarketable.
Citrus trees may not show signs of infection for several years. The initial signs may be misidentified as a zinc deficiency or another disease. DNA analysis is the only definitive method of diagnosis.
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