Comparative study on biological parameters of Bemisia tabaci (Genn.) collected on four host plants from Varamin-Iran

During 2003 biological parameters of sweetpotato whitefly, B. tabaci (Genn.) (Horn. Aleyrodidae) as a major pest of field crops, vegetables and ornamentals were studied. In this study, the infested leaves of cucumber (Cucumis sativus L.) zucchini (Cucurbita pepo L.) eggplant (Solanum melongena L.) and cotton (Gossypium hirsutum L.) with whitefly nymphs and pupae were collected from Varamin-Iran, and were transferred to the laboratory. The newly emerged males and females of each population were released separately into a large cage set on cotton plants. Experiments were carried out in a growth chamber on cotton, (Varamin 76 variety) at 24+/-2 degrees C, 55+/-3% RH and 16:8 h (L: D) photoperiod. The adults of every collected population after emergency were reared in the large cages (40 x 50 x 70) containing pots of cotton plant. The preimaginal developmental time and reproductive parameters of 40 mated females were calculated for each population. The results revealed that the intrinsic rates of increase (r(m)), on cucumber, zucchini, eggplant and cotton were 0.093, 0.068, 0.085 and 0.078 respectively, gross fertility rate, were 67.92, 59.08, 76.13 and 63.14 respectively and mean generation time (T(c)) were 27.4, 27.74, 27.73 and 27.52 days respectively. Other demographic parameters such as intrinsic birth rate (b), intrinsic death rate (d), finite rate of increase (lambda), doubling time (DT), net fecundity rate, net fertility rate , gross fecundity rate, mean age gross fecundity and fertility, mean age net fecundity and fertility, mean age hatch, number of eggs/female/day and daily reproductive rate were also calculated. The results revealed that there were not significant differences between parameters of demography in different populations and the host plant has no significant influence on biological parameters.