New Disease Reports (2011) 23, 2. [doi:10.5197/j.2044-0588.2011.023.002] New isolates of Citrus tristeza virus naturally occurring in old lemon and mandarin trees in Greece

Citrus tristeza virus (CTV) has quarantine status in Greece. The virus was first reported in 2000 in non-certified sweet orange trees grafted on CTV-tolerant Carrizo citrange originating from Spain (Dimou et al., 2002). High homology of these isolates was then found with the Spanish mild T385 isolate (bio-group 1, Garnsey et al., 2005) from sweet orange grafted on sour orange rootstock, sharing 100 % nucleotide sequence identity for the p20 gene (Varveri, 2006). In 2009, surveys were conducted in the area of Poros (Trizinia, Prefecture of Pireaus), where about 20,000 citrus trees grow, mainly lemon. (This was an area previously devoted to citrus cultivation for more than 100 years but now consisting virtually of a wood protected only for its beauty and historical importance). A total of 285 citrus trees, 87 % of which were lemon, were tested by ELISA (Enzyme-Linked Immunosorbent Assay) in a programme lasting until September 2010. Six trees (four lemons and two mandarins) were found positive. None of the above mentioned trees showed any symptoms