ABSTRACT
This chapter is devoted to providing an overview of the taxonomic aspect of the whitefly, taking into account the existence of biotypes and the role of endosymbiotic bacteria in the determination of these biotypes. This research area had hitherto remained unexplored on account of the non-availability of techniques. Bemisia tabaci was considered as a complex of many species and it is widespread. It has been found in tropical, subtropical, and temperate zones throughout the world. It is a well-known fact that Bemisia tabaci has two biotypes based on location namely B-Biotype (Bemisia argentifolii) (MEAM1) and Q-Biotype (MED). Portiera, Hamiltonella, Cardinium Arsenophonus, Fritsche, Rickettsia were analyzed to determine their biotypes. The information gathered on the differential response of whitefly from varied locations showed the presence of more biotypes, taking into consideration, host plants, response to pesticide, presence of endosymbionts, vector ability /virus transmission, etc. The modern and highly sensitive techniques such as RAPD-PCR, AFLP, mtCO1 and 16 s ribosomal ITSI microsatellites, CAPS and SCAR, mtCO1 were applied to different genetic groups were based on region; a new biotype ‘NW’ (NW:new world) was determined in Brazil. Likewise, many biotypes yet to be named have been determined. The existence of a new biotype in southern India has been demonstrated but the name has not been given. Similastudies at different locations were conducted and demonstrated the presence of new biotypes but names of these biotypes are still needed. This chapter also reports the presence of 7 morphs being determined in Punjab, India based on a differential response to the pesticide. Additionally, the identification of endosymbionts and their presence in terms of species and extent of endosymbionts have been analyzed. The detailed information on the presence of primary endosymbionts in all whitefly populations and the varying presence of secondary symbionts has been given. The symbionts and their role have also been discussed in detail.
