Host plant performance, esterase, and virus transmission tests revealed cassava-strain and sweetpotato-strain populations of whitefly Bemisia tabaci (Gennadius) biotypes in India. Individuals from the sweetpotato-reared population did not breed on cassava, Manihot esculenta Crantz, and the cassava-strain-reared individuals failed to develop on sweetpotato, Ipomoea batatus (L.) Lam. Eggplant, Solanum melongena L., and tobacco, Nicotiana tabacum L., were common hosts for both biotypes. The cassava-strain whiteflies but not the sweetpotato-reared whiteflies successfully transmitted cassava mosaic virus from disease-infected cassava seedlings to healthy cassava seedlings. Presence of biotypes in B. tabaci is reported for the first time from India.