The plant world is an excellent source of bioactive molecules such as alkaloids, polyphenols, triterpenes, which gives it an important bioinsectiside activity. In order to know the biological activities of medicinal plants traditionally used by the population, our work focused on the study of the crude extracts of the leaves of Urtica dioica L. (Urticaceae) on the mortality and feeding behavior in the larvae of Drosophila melnogatser and the sexual and reproductive behavior in the adults of the fly, using aqueous extracts of this plant. The treatment is done by ingestion on 2nd instar larvae (L2). The results show that mortality rates can reach 50% after 15 days of treatment, we also recorded that the aqueous extract of U. dioica L. does not attract the larvae (control and treated) of D. melanogatser as it disturbs their olfactory system or the majority of the tested larvae present random choices. The aqueous extract of U. dioica L. suppressed and blocked mating sequences in treated and control male-female pairs. U. dioica L. also reduces reproductive capacity in treated females and does not attract females (control and treated) to lay eggs (repellent effect), confirming that the bioactive molecules present in the aqueous extract of U. dioica L. are repellent allelochemicals.