Molecular studies on biotypes of whitefly, Bemisia tabaci: A vector of cassava mosaic disease

The genetic polymorphism and the biotype identity of the whitefly, Bemisia tabaci (Genn.) have been studied in population samples taken from different localities within Tamil Nadu, during 2009–2010 from cassava and crop intercropped with cassava at early stage of cultivation. Two different approaches were used for identifying Q and B biotype viz., mitochondrial cytochrome oxidase I (mtCOI gene) genotype was used for identifying Q biotype and 16S mitochondrial DNA (16S mt DNA) genotype was for B biotype. The biotyping results revealed that Q and B biotype coexisted only on cassava, tomato and sunflower under natural conditions. However, Q biotype existed as a sole biotype on tobacco, brinjal and green gram and on the other hand B biotype was noticed as a sole biotype only on bhendi.