Résumé
Since 1997, Tomato yellow leaf curl virus (TYLCV) has been responsible of great losses on tomato production in Réunion island. B. tabaci infestations were not observed on vegetable crops before the detection of TYLCV in 1997, although B. tabaci had been reported several times in the island since 1938. After 1997, two haplotypes of B. tabaci were differentiated in Reunion using RAPD, COI and microsatellite markers. One haplotype correspond to biotype B and is supposed to have been recently introduced, whereas the other one is distinct from any haplotype analysed so far. Since the latter haplotype was also found in Madagascar, Mauritius and Seychelles, it was considered native from the South west of the Indian Ocean and was named Ms. The distribution of both haplotypes was studied throughout Reunion using a genotyping technique based on microsatellites markers. B. tabaci was sampled in 30 different locations typical of the various ecosystems found in Reunion. Wherever possible the whiteflies were collected on crops and weeds to investigate an eventual host specificity of the haplotypes. The B biotype was mainly found in vegetable crops and its geographic distribution differed from the Ms distribution. Future equilibrium between the invasive and the indigenous haplotype is discussed regarding to virus epidemiology. (Résumé d'auteur)