Bemisia tabaci (Gennadius): From Complex Species to a Species-Complex

The whitefly, Bemisia tabaci (Gennadius), a cryptic species-complex, encompasses a number of morphologically indistinguishable species which differ genetically from each other. It probably represents the highest number of biotypes or genetic groups than any other species in the order Hemiptera. The pest is distributed over almost all regions of the world with high economic impact owing to its direct feeding effect as well as vector of many plant viruses. Since the emergence of its invasive B-biotype in 1980s, novel genetic groups are being reported from different regions of the world based on biochemical techniques and mitochondrial CO1 gene sequences. With only few biotypes identified in early 1990s, reports of new genetic species are increasing in recent years. Here, we present in this review, the progress made in the identification and classification of different genetic groups within this species-complex. Besides, its role as a plant virus-vector and management aspects are also discussed.