RESUMEN
Abstract: Bemisia tabaci (Asia II 5) and Trialeurodes vaporariorum are the two devastating species of whiteflies infesting a wide range of vegetable crops in the North-Western Himalayan region. Therefore, the present investigation deals with a comparative study of the morphology and developmental biology of these two whitefly species. The total developmental period from egg to adult was 22.82 and 23.40 days for B. tabaci (Asia II 5) and T. vaporariorum, respectively, which did not differ significantly. The adult longevity, fecundity, and adult emergence in T. vaporariorum is quite higher than B. tabaci (Asia II 5) which were observed as 10.40 days, 118.00 eggs/female, 90.69 per cent and 6.80 days, 73.33 eggs/female, 86.59 per cent, respectively. Similarly, the egg hatching and the survival rate is higher in T. vaporariorum than in B. tabaci (Asia II 5) (95.11, 81.44 per cent and 91.68, 78.09 per cent). Morphological characters such as marginal setae, abdominal setae, vasiform orifice, lingula, and antennae, which were reliable characters for the identification of both whitefly species and diagnostics of the two whiteflies, were explicated in a comparative discussion.