First report of Tobacco ringspot virus in the Czech Republic
The NPPO of the Czech Republic recently informed the EPPO Secretariat of the first* record of Tobacco ringspot virus (Nepovirus, TRSV – EPPO A2 List) on its territory. During an official inspection, TRSV was detected in 1 nursery in November 2011. During this inspection, leaf samples were taken from mother plants of Impatiens walleriana showing chlorotic rings and patterns. Samples were tested (ELISA) by the NPPO laboratory and found positive for TRSV. The identity of the virus was confirmed by biological tests on indicator plants and PCR by the reference laboratory in Prague. Because TRSV infections can be symptomless on many plants, a specific survey was conducted on all ornamental species grown in the glasshouses of the company concerned. TRSV was detected in all lots of mother plants of I. walleriana but it was not detected on any other potential hosts (including mother plants of Impatiens New Guinea hybrids). The presence of its main nematode vector, Xiphinema americanum (absent from the Czech Republic), in the glasshouses was checked by laboratory analysis of soil samples. All results were negative. It is assumed that TRSV has been introduced into the premises with infected plants and that it was then spread among I. walleriana plants by vegetative propagation. However, in the absence of nematode vectors, it did not spread to other plant species. The origin of this introduction could not be traced back. Many plants (cuttings) produced from the infected mother plants have been sold to other growers or final consumers within the Czech Republic. The tracing forward of deliveries to other growers is on-going and for the moment no export to other EU countries has been identified.
Official measures have been taken to eradicate TRSV in the premises concerned and prevent any further spread. All lots of I. walleriana mother plants and their cuttings were destroyed. Further testing of I. walleriana for TRSV will be carried out in the Czech Republic.
The pest status of Tobacco ringspot virus in the Czech Republic is officially declared as: Transient, actionable, found on Impatiens walleriana in one company under protected conditions in 2011, under eradication.
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* A 'first record' of TRSV was entered into PQR in 1993 for Czechoslovakia but could not be traced back (the list of pests sent by the Czech NPPO at that time did not contain TRSV). The EPPO Secretariat now considers that this was most probably a data entry error.
Sources
NPPO of the Czech Republic (2012-03).