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May 22, 2003
First Report of Cucurbit yellow stunting disorder virus in commercial cucumber greenhouses in France
Source: Amer Phytopathol Soc, DISEASE NOTES [edited]

C. Desbiez, H. Lecoq, M. Girard, INRA, Station de Pathologie Vegetale; A. C. Cotillon, LNPV, Domaine Saint Maurice, 84140 Montfavet, France; and L. Schoen, Sica Centrex, 66440 Torreilles, France. Plant Dis. 87:600, 2003; published on-line as D-2003-0312-01N, 2003. Accepted for publication 26 Feb 2003.

In autumn 2001, severe yellowing symptoms were observed on greenhouse-grown cucumbers near Perpignan in southern France. Leaf samples were collected from 2 sites where plants displayed symptoms ranging from limited yellowing of the older leaves to severe, complete yellowing of the whole plant.

Cucurbit aphid-borne yellows polerovirus that causes similar symptoms was not detected in DAS-ELISA using a specific antiserum.

Total RNA was extracted from fresh leaf tissues and used in RT-PCR(1) with primers specific for 2 whitefly-borne viruses that also induce yellows in the Mediterranean basin (1): Beet pseudo-yellows closterovirus (BPYV) transmitted by _Trialeurodes vaporariorum_ (West.) and Cucurbit yellow stunting disorder crinivirus(CYSDV) transmitted by _Bemisia tabaci_ (Genn.).

No BPYV was detected in the autumn survey, but CYSDV was present in all samples. In subsequent surveys conducted in the spring and summer of 2002, BPYV and CYSDV were detected, sometimes in mixed infections, in samples collected from the same region. The complete CYSDV coat protein gene was
amplified by PCR using specific primers (2), yielding the expected-size fragment of 756 bp.

The French isolate (GenBank Accession No. AY204220) shared 99.6 to 100 percent nucleotide sequence identity in the sequenced CP fragments (700 nt) with isolates of the most common, highly homogenous subgroup of CYSDV that has emerged recently in the Middle East, southwestern Europe (Spain and Portugal), United States, and Morocco (2).

To our knowledge, this is the first report of CYSDV in France and it shows the threat represented by the current emergence of _B. tabaci_-transmitted viruses.

References:

(1) I. C. Livieratos et al. Plant Pathol. 47:362, 1998.
(2) L. Rubio et al. J. Gen. Virol. 82:929, 2001.

[Yellowing diseases of cucurbits (watermelon, melon, cucumber) have been reported in southern regions of Europe for many years. CYSDV, a crinivirus transmitted by the whitefly _Bemisia tabaci_, is the main virus, displacing the aphid-transmitted beet pseudoyellows. Significant yield losses occur, especially in crops grown under cover (glasshouses, plastic tunnels). The disease occurs in the EPPO region (Israel, Jordan, Morocco, Portugal, Canary Islands, and Turkey), Asia (Lebanon, Saudi Arabia, United Arab
Emirates), Africa (Egypt), and North America (Mexico, Texas). Officials in the EU are concerned that CYSDV could spread to other countries. Farmers in Lebanon report losses of 40 to 60 percent. Disease management depends on reducing vector populations, elimination of sources of infection, and the use of virus-free transplants. - Mod.DH]