December 28, 2005
From: ProMED-mail<promed@promedmail.org>
Source: British Society for Plant Pathology, New Disease Reports, Vol. 12 [edited] <http://www.bspp.org.uk/ndr/jan2006/2005-102.asp>

First report of Tomato chlorosis virus (ToCV) on tomato crops in Cyprus
L.C. Papayiannis, Agricultural Research Institute, P.O.B. 22016, 1516 Nicosia, Cyprus; N. Ioannou (as for Ioannou); C.I. Dovas, National Agricultural Research Foundation (NAGREF), Plant Protection Institute of Thessaloniki, P.O.B. 324, Thermi 570 01, Thessaloniki, Greece; V.I. Maliogka, Aristotle University of Thessaloniki, Faculty of Agriculture, Plant Pathology Laboratory, P.O.B. 269, 54 124 Thessaloniki, Greece; and N.I. Katis (as for Maliogka). Accepted for publication 16 Dec 2005.

In the summer of 2004, yellowing symptoms similar to those caused by nitrogen and magnesium deficiency were observed in field- and greenhouse-grown tomatoes (_Lycopersicon esculentum_) in the Parekklisia area of Cyprus. Initially, lower leaves showed extensive interveinal yellowing with necrotic flecks, brittleness and
occasional upward leaf rolling before, finally, the whole plant turned yellow. Similar symptoms were observed during 2005 in greenhouse tomatoes grown in areas located on the southwest coastal region of the island.

The abundance of whiteflies on the affected plants suggested the involvement of the whitefly-transmitted Tomato chlorosis virus (ToCV) and/or Tomato infectious chlorosis virus (TICV); both of the genus _Crinivirus_ (Wisler et al., 1998).

Leaves of 18 symptomatic plants were collected; total RNA was isolated and RT-PCR was performed in a single tube using primers HS-11 and HS-12, followed by a multiplex nested-PCR with primers TIC-3 / TIC-4 and ToC-5 / ToC-6, for the detection of TICV and ToCV, respectively (Dovas et al., 2002). A PCR product of 463 bp, corresponding to the HSP 70 gene of ToCV, was amplified for all tested samples.

The sequences of 4 cloned PCR products were identical (EMBL accession number AM158958) and showed 99 percent nucleotide identity to a ToCV isolate from Florida (accession number AY903448). ToCV is vectored by _Bemisia tabaci_ [Bt] (biotypes A and B), _Trialeurodes vaporariorum_ and _T. abutilonea_. Although there have been no systematic studies on Bt incidence and distribution in Cyprus, it seems that it is the predominant species present, as Tomato yellow leaf curl virus (Ioannou, 1985) and Cucurbit yellow stunting disorder virus (Papayiannis et al., 2005), vectored by this species, are prevalent in tomatoes and cucurbit crops, respectively. On the other hand, the incidence of Beet pseudo-yellows virus (transmitted by _T. vaporariorum_) is much lower.

To our knowledge this is the first report of ToCV in Cyprus.

References:

Dovas CI, Katis NI, Avgelis AD, 2002. Multiplex detection of criniviruses associated with epidemics of a yellowing disease of tomato in Greece. Plant Disease 86, 1345-1349.

Ioannou N, 1985. Yellow leaf curl and other virus diseases of tomato in Cyprus. Plant Pathology 34, 428-434.

Papayiannis LC, Ioannou N, Boubourakas IN, Katis NI, Falk BW, 2005. Incidence of viruses infecting cucurbits in Cyprus. Journal of Phytopathology 153, 530-535.

Wisler GC, Li HY, Lowry DS, Duffus JE, 1998. Tomato chlorosis virus: a new whitefly-transmitted, phloem-limited, bipartite closterovirus of tomato. Phytopathology 88, 402-409.

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[Criniviruses are an emerging genus worldwide, containing new species that have evolved over time and are now evident as causal agents of new plant diseases. Their symptoms are easily mistaken for those of physiological or nutritional disorders or pesticide phytotoxicity, thus confounding their identification. Criniviruses remain confined
to cells associated with the plant phloem, and symptoms are considered to result from plugging of the phloem with large viral inclusion bodies, thus likely interfering with normal vascular transport in infected plants. Both TICV and ToCV were 1st reported during the 1990s in the United States, and ToCV has been reported to occur in the Mediterranean countries, Portugal, Spain, and Italy.

ToCV and TICV are commonly restricted to tomato greenhouse production systems. Fruit size and number appear reduced by ToCV infection. Disease management involves raising and maintaining Bt-free tomato transplants. To prevent entry of the various vectors into production sites, greenhouses and screenhouses have to be constantly monitored for the presence of vectors. Use of approved chemical insecticides can reduce disease incidence. Florida producers can obtain recommended information from the latest Insect Management Guide.

Links:
<http://www.apsnet.org/online/feature/whitefly/>
<http://edis.ifas.ufl.edu/PG059>
<http://www.agnic.org/agnic/pmp/2005/tcv072505.HTML>
<http://www.ipm.ucdavis.edu/PMG/r783301211.html>
<http://www.agf.gov.bc.ca/cropprot/tomatoviruses.htm>
<http://image.fs.uidaho.edu/vide/descr829.htm>
<http://www.eppo.org/QUARANTINE/Alert_List/viruses/tmicxx.htm>
<http://www.eppo.org/QUARANTINE/Alert_List/deletedpercent20files/virus/Tomato_chlorosis_crinivirus.doc>
- Mod.DH]

[see also in the archive:
Tomato chlorosis, tomato - France (Reunion Island): 1st report 20050605.1566
Tomato criniviruses - France: 1st report 20051122.3397
2004
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Tomato chlorosis virus, tomato - Israel:1st report 20041019.2834
2002
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Tomato chlorosis virus - Morocco 20020731.4904
Tomato criniviruses, detection - Greece 20021130.5939
2001
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Tomato chlorosis crinivirus disease - Puerto Rico 20010324.0588
Tomato chlorosis crinivirus - Puerto Rico 20010515.0942
2000
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Tomato chlorosis crinivirus - Portugal: EPPO report 20001129.2080
1999
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Tomato chlorosis virus, new - USA 19990125.0120
1997
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Tomato chlorosis virus: Diagnosis 19970319.0582]