Abstract: Whitefly (Bemisia tabaci Genn.) is a widely distributed and highly harmful plant pest species. The management of B. tabaci has been typically carried out by chemical pesticides. In the last decade however, there has been an increasing interest in natural products, particularly those of plant origin, to control this pest species. In the present work, aqueous extract of Couroupita guianensis plant was evaluated for insecticidal activity against eggs, nymphs and adults of Bemisia tabaci, on tomato plant grown in the greenhouse condition. In a separate experiment, C. guianensis extract treatment was tested for repellency. The aqueous extract showed low insecticidal effects on B. tabaci eggs. However, nymphs and adults were more sensitive towards C. guianensis treatment. The C. guianensis extract reduced the survival rate of B. tabaci by 19.2%, 29.2% and 35.34% after treatment of eggs, nymphs and adults, respectively. Overall, results suggest that the aqueous extracts of C. guianensis leaves show high insecticidal effects on nymphs and adult flies whereas low effect on the eggs of B. tabaci as compared to control. The results revealed that the tested material exhibited reasonable insecticidal activity against all the stages of whiteflies. Hence, the extracts from C. guianensis plant could be used as an effective and environmentally sustainable bio-insecticide for the control of whiteflies, Bemisia tabaci.