Citrus from family Rutaceae and subfamily Aurantioidae, is grown widely in the tropical and subtropical zones between 40° north and south latitudes. According to the report of Food and Agricultural Organization (FAO) of united nations, Iran ranks seventh among the citrus producing countries of the world and Mazandaran province is the first rich-citrus province in Iran with over 90/000 hectares under citrus cultivation and production about 1.8 million tons. Citrus are infected by a wide range of virus and virus-like pathogens. Psorosis disease is one of the most important viral diseases of citrus that is widespread and causes serious losses. The infected trees by Psorosis A show interveinal chlorotic spots in young leaves of spring flash leaves. The chlorotic spots may occur in whole or some parts of the leaves. Psorosis B is the more aggressive form of the disease and causes severe bark scalling in trunk and young branches. Affected trees also show ringspots and chlorotic spots in old leaves, with brownish gum on leaf underside. Citrus psorosis virus (CP S V), the type species of the genus Ophiovirus causes psorosis disease. This study was aimed to detect and determine certain biological and molecular properties of Citrus psorosis virus in Mzandaran province. In 2009 and 2010, the leaf samples of infected trees showing bark scaling on trunk and main limbs, ring spot and oak leaf pattern on leaf and ring pattern on fruits were collected. The samples were tested by triple antibody sandwich ELISA (TAS ELISA) using 13c5 and A326 monoclonal antibodies. To determine certain biological characteristics of CPsV, indexing was performed on 11 varieties of citrus including tangor, clementine, unshu, lemon, lime, thamson, grapefruit, sour orange, citrange and citrumelo. The collected samples were subjected to double stranded-RNA (dsRNA) extraction by CF-11. The TAS-ELIS was conducted with some modifications and best results obtained when 13c5 (200 µl per well) was used as coating (1/4000 dilution) and the second antibody (1/1000 dilution). Sixteen and six out of 30 samples were determined as positive and suspected samples in ELISA, respectively. Electrophoretical patterns of dsRNA showed two bands (larger than 10000 bp and 1700 bp) on agarose gel in all ELISA positive samples.
