January 31, 2003
From: EPPO Reporting Service 2003, No. 11 [edited]

2003/172
Details on the situation of Tomato yellow leaf curl begomovirus in Reunion

In Reunion, Tomato yellow leaf curl begomovirus (EPPO A2 list) was first reported in September 1997 near St. Pierre. The virus was found both in protected and field-grown tomatoes, causing serious epidemics. In 1998, it was considered that eradication was not feasible, but control programmes were initiated. Molecular studies of isolates from Reunion suggested that they correspond to a single recent introduction from a single origin.

Studies on the insect vector, _Bemisia tabaci_ [Bt] (_Homoptera_: _Aleyrodidae_ - EPPO A2 list), showed that the Bt predominates on the island, but some specimens belonged to another biotype (also present in Madagascar, Mauritius, Seychelles and designated biotype Mascareignes). In 1998/1999, surveys showed that TYLCV was present from La Possession (north) to St. Joseph (south), and to Makes towards the centre of the island (900 m altitude). The eastern part of the island was not affected by TYLCV, but it is not a tomato-producing area.

No specific studies were done on crop losses, but losses up to 85 percent were observed on the most susceptible tomato cultivars (e.g. Farmer, Boa). Control measures are being taken to contain both TYLCV and its vector. In nurseries, insect-proof screenhouses and yellow sticky traps are used, and planting material is tested. Growers are recommended not to establish new tomato crops in the vicinity of old plots, to apply weed control, chemical or biological control against Bt, and to use more tolerant tomato cultivars. Import checks have been also strengthened to avoid further introductions of infested tomato fruits or plants, and of Bt.

Source:
Reynaud, B.; Wuster, G.; Delatte, H.; Soustrade, I.; Lett, J.M.;
Gambin, O.; Peterschmitt, M. (2003) Les maladies a begomovirus chez la tomate dans les departements francais d'Outre-Mer. Le Tomato yellow leaf curl virus (TYLCV) a la Reunion. Phytoma - La Defense des Vegetaux no. 562, 13-17.

[Tomato yellow leaf curl disease is well-established in the country after 7 years of cropping. Genetic resistance to TYLCV in tomato cultivars appears to controlled by at least 5 genes, and crossing experiments yielded only tolerant hybrids. Production of genetically engineered tomato is a possible management strategy.

Useful references:
<http://www.arc-avrdc.org/pdf_files/002-Lieu_18th.pdf>
<http://gcrec.ifas.ufl.edu/tgc/newsletters/vol41/vol41/v41p19b.html>
- Mod.DH]