Since 1997, Tomato yellow leaf curl virus (TYLCV) has been responsible of great losses on tomato production in Réunion Island. Bemisia 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 genotypes of B. tabaci were differentiated in Réunion using RAPD-PCR and sequencing of a portion of a mitochondrial gene encoding cytochrome oxydase I. One was identified as biotype B and is supposed to have been recently introduced in Réunion, whereas the other is distinct from any genotype analysed so far. Since the latter genotype 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 biotypes was studied throughout Réunion using a genotyping technique based on microsatellites markers. B. tabaci was sampled in 30 different locations typical of the various ecosystems found in Réunion. Wherever possible the whiteflies were collected on crops and weeds to investigate an eventual host specificity of the biotypes. (Texte intégral)