USDA - APHIS - Plant Health, Plant Protection and Quarantine

Citrus Greening

Citrus greening, also called Huanglongbing or yellow dragon disease, is one of the more serious diseases of citrus. This bacterial disease is thought to have originated in China in the early 1900s. The disease is primarily spread by two species of psyllid insects. One species, the Asian citrus pysllid, Diaphorina citri, has been present in Florida since 1998. The bacteria itself is not harmful to humans but the disease has harmed trees in Asia, Africa, the Arabian Peninsula, and Brazil. There are three strains of the bacteria, an Asian, an African version, and a recently described American strain discovered in Brazil.

The Asian strain, Candidatus Liberibacter asiaticus was found in Florida in early September, 2005. To respond to the problem, USDA, APHIS, PPQ and the Florida Department of Agriculture and Consumer Services deployed a Unified Command under the Incident Command Structure, and delimiting survey crews are working in southern Florida to define the extent of the problem.