Activité biologique de l'extrait de graines de Peganum harmala sur le criquet pèlerin (Schistocerca gregaria Forskål 1775)

Abstract The effect of an extract of Peganum harmala seeds was studied on the 5th larval instar and on the ovarian growth of desert locusts under laboratory conditions. The results obtained show, in the 5th larval instar, an 8–d delay of imaginal moulting, and a mortality rate of 100%, reached on the 16th day after the beginning of the treatment. In females treated at the adult instar, 62.5% among them had their ovarian development blocked. Those surviving showed an 8–d delay of egg–laying and a decrease in hatching rate. We have noted, in the treated insects, a decrease in physical activity (immobility, trembling of appendages), a decrease in weight, and a loss of water in the form of wet faeces. Concurrently, a phytochemical study conducted on the same ethanolic extract has shown the presence of a majority of the indolic alkaloids responsible for the toxicity of the plant.