First report of Citrus tristeza closterovirus in Sudan
So far, no studies other than visual inspections had been done on citrus viruses occurring in Sudan. In Sudan, most citrus are grafted on sour orange rootstocks which are susceptible to Citrus tristeza closterovirus (CTV - EPPO A2 list). A survey on citrus viruses was initiated in 2003 and 2004. Symptomatic leaves were collected and tested by immunoprinting and nested RT-PCR. CTV was detected in 13 leaf samples using a mixture of specific monoclonal antibodies. 10 samples had been collected from orchards of orange trees (Citrus sinensis), 2 samples came from a mandarin (C. reticulata) and 1 from a lime tree (C. aurantifolia). The presence of CTV was confirmed by nested RT-PCR in 4 citrus trees (3 orange and 1 lime tree) which had previously given positive results with immunoprinting. Further molecular tests will be carried out to verify the presence of CTV in other citrus orchards in Sudan. According to the EPPO Secretariat, this is the first report of CTV in Sudan.
The situation of Citrus tristeza closterovirus in Sudan can be described as follows: Present, detected for the first time in 2003/2004 on few samples, further studies are underway to confirm its occurrence.
Sources
Abubaker M, von Bargen S, Bandte M, Elhassan S, Büttner C (2005) Investigation on Citrus tristeza virus (CTV) and its occurrence in citrus orchards in arid and semi arid zones of Sudan. Phytomedizin. Mitteilungen der Deutschen Phytomedizinischen Gesellschaft, Braunschweig no. 3, 29-30.