Survey of Citrus Huanglongbing (greening disease) on the Amami islands. 1. Characteristics of distribution in the Amami islands

Citrus Huanglongbing (syn. greening disease) caused by 'Candidatus Liberibacter asiaticus' were surveyed on the Amami islands from 2002 to 2006. A total of 212, 587 Rutaceae plants were surveyed at 29, 063 sites on the Amami islands. Samples that showed a greening-like symptom (17, 384 samples) were examined by a polymerase chain reaction (PCR) assay according to the method of Jagoueix et al. (1994). Of these, 1, 041 (0.5%) samples were identified as being infected with 'Candidatus L. asiaticus.' These infected samples were found on the Kikai-jima, Tokuno-shima, Okierabu-jima, and Yoron-tou islands; however, infected samples were not found in Amami-O-shima (Amami main island).