Citrus tristeza virus variants and their distribution in mandarin orchards in northeastern Himalayan Hill region of India

Northeastern Himalayan hill region of India is known to produce quality mandarin (C. reticulata) commercially. Citrus tristeza virus (CTV), an aphid (Toxoptera citricidus) transmitted closterovirus, is a major problem to cause decline of mandarin in this region. The different orchards of Mirik in the Darjeeling and Rumtek of East Sikkim were surveyed. CTV incidence of 48-53.3% in Mirik and 40-60% in Rumtek were estimated using direct antigen coated-ELISA and polymerase chain reaction.