Aphis gossypii Glover is one of the most important pests in greenhouse and field plants. Considering the importance of human health and the environmental protection, reduction of pesticide use in the pest control program is essential. The experiment was performed with 25 replicates for each concentration of each treatments consisting of plant extract, imidacloprid, control 1 (distilled water, as control for insecticide) and control 2 (water+ Tween+ ethanol, as control for the plant extract). Therefore, in the present study, effects of sublethal concentration (LC30) of ethanolic extract of Eucalyptuscamaldulensisand imidacloprid was tested on the aphids using dipping method. Reproduction and mortality rates of aphids on cucumber leaves were counted in the laboratory conditions. Based on the results obtained in the imidacloprid, plant extract eucalyptus and control 1 and 2, respectively the net reproductive rate (R0), was 4.32 ± 0.14, 14.89 ± 0.57 and (control 1 and 2, respectively was to 55.21 ± 0.11 and 49.50 ± 0.13 female/female, intrinsic rate of increase (rm) was 0.18 ± 0.03, 0.32 ± 0.02 and 0.41 ± 0.005 female/female/day, finite rate of population increase (λ) was 1.20 ± 0.004, 1.39 ± 0.02 and 1.51 ± 0.004 female/female/day, mean generation time (T) was 7.97 ± 0.05, 8.42 ± 0.00 and 9.42 ± 0.00 day, the population doubling time (DT) was 2.38 ± 0.001, 1.84 ± 0.06 and 1.57 ± 0.001 day. This information provides support for E. camaldulensis having a role in aphids control.