HUANGLONGBING: CAUSAL DISEASE FOR DECLINE OF CITRUS RETICULATA AND CITRUS MACROPTERA PRODUCTION IN TRIPURA, NORTHEAST INDIA

‘Huanglongbing’ (HLB), previously known as ‘citrus greening’ is a severe and widespread disease of citrus caused by ‘ Candidatus Liberibacter spp.’ Major citrus cultivation of Tripura produced in the north district were surveyed and detected with HLB symptoms. Characteristic symptoms of HLB viz. blotchy mottle leaves, yellow veins and severe chlorosis were observed. A preliminary survey of citrus orchards in the Northern district of Tripura revealed that 16-20% of trees are symptomatically affected with HLB disease. Diagnosis of HLB in two citrus species, Citrus reticulata (Mandarin) and Citrus macroptera (Satkara) were substantiated by conventional polymerase chain reaction (PCR). OI1 and OI2c primers which are specific to 16S rDNA of the pathogen ‘ Candidatus Liberibacter asiaticus’ amplified a DNA fragment of 1160 bp. This study validates the causal factor of the drastic decline of citrus cultivation in Tripura.