July 6, 2003
Source: American Phytopathological Society, DISEASE NOTES [edited]

First Report of Tomato infectious chlorosis virus in Tomato in Indonesia
J. Th. J. Verhoeven, T. M. Willemen, and J. W. Roenhorst, Plant Protection Service, Section Virology, P.O. Box 9102, 6700 HC Wageningen, the Netherlands; and R. A. A. van der Vlugt, Plant Research International, P.O. Box 16, 6700 AA Wageningen, the Netherlands. Plant Dis.87:872, 2003; published on-line as D-2003-0506-02N, 2003. Accepted for publication 15 Apr 2003.

In 2002, a breeding company submitted several samples of tomato (_Lycopersicon esculentum_) for diagnosis. Samples originated in Indonesia and were taken from protected and nonprotected crops. Plants exhibited severe chlorosis on fully expanded leaves, while young leaves were symptomless.

Symptoms resembled those of the criniviruses Tomato chlorosis virus (ToCV) and Tomato infectious chlorosis virus (TICV). Moreover, large numbers of whiteflies, potential vectors of these viruses, had been observed at the plots with symptomatic plants.

A reverse transcription-polymerase chain reaction (RT-PCR) with specific primers for TICV (1) yielded amplicons of the expected size of approximately 500 bp for all samples. One of the amplicons was sequenced (Genbank Accession No. AY221097) and revealed more than 98.9 percent identity to 6 isolates of TICV in NCBI Genbank.

cDNA synthesis using the universal crinivirus primer HSP_M2-DW (5'-TCRAARGTWCCKCCNCCRAA-3') followed by PCR with a ToCV specific primer set (ToCV-UP 5'-TCATTAAAACTCGGGACCGAG-3' and ToCV-DW 5'-GCGACGTAAATTGAAACCC-3') was negative in all cases.

Grafting of symptomatic shoots onto healthy tomato seedlings of cv. Money-maker showed transmission of the virus, as chlorosis appeared on fully expanded leaves of lateral shoots after 6 weeks.

The presence of TICV in the graft-inoculated plants was confirmed by RT-PCR. Furthermore, mechanical inoculation to a range of herbaceous test plants did not evoke any virus symptoms, indicating the absence of mechanically transmissible viruses.

Although other nonmechanically transmissible viruses cannot be fully excluded, the results together with the symptoms observed, indicate that TICV is the cause of the disease.

TICV has been reported from Greece, Italy, Japan, Spain, and the United States, but to our knowledge, this is the first report of TICV in Indonesia.

Reference:
(1) A. M. Vaira et al. Phytoparasitica 30:290, 2002.

[ToCV is transmitted by the greenhouse whitefly, _Trialeurodes vaporariorum_, and is a nasty pest, especially in glasshouse operations. Although it can cause severe crop losses in fresh market and glasshouse-produced tomatoes, damage is generally minor. It also infects several other food crops monitored by ProMED-Plant such as lettuce (_Lactuca sativa_) and potato (_Solanum tuberosum_). Disease management requires use of virus-free transplants, avoidance of susceptible hosts, especially weeds, roguing of infected plants, and control of insects by insecticides. - Mod.DH]