Introduction: The henna plant Lawsonia inermis L.,is one of the oldest cosmetic, medicinal and aromatic plants, well known in the worldwide. Objective: This study is the optimization of the extraction of the essential oil from the aerial part of Lawsonia inermis L plant. Two methods of extraction were compared; the hydrodistillation and the microwaves extraction, from the leaves, the flowers and the seeds of henna plant. The obtained essential oil was analyzed in laboratory to determine its organoleptic and physicochemical proprieties. Results: The main result is that the flowers of henna yielded more essential oil than the leaves and the seeds respectively, the obtained essentials oils by the sited methods of extraction are quantitatively and qualitatively similar with fair differences in yield an chemical proprieties, may due to the extraction times, even that they are conformed to AFNOR norms.

The study was carried to evaluate the effect of the essential oil of henna's leaves on the biological aspects (egg, larvae and adults stages) of Parlatoria blanchardi. The insect is one of the serious pest infected the date palm cultivated in Algeria. The sample of leaves of date palm infested by the insect putted in Petri dishes were treated under the laboratory conditions with 05 treatments (C0, C1, C2, C+, C-); two were obtained by the dilution of the essential oil (the concentration of 5 % and 20 % of essential oil) and three controls (two negative controls and an insecticide as positive control).The results obtained in the earliest 06 days of the experimentation, showed that the two treatments of the essential oil caused high mortality on different stages of Parlatoria blanchardi, close to those obtained with the control with a delay of one day.