Insecticidal Potency of Aqueous Extracts of Seeds and Leaves of Harmal Peganum Harmala (Zygophyllaceae) on Juveniles of Calliptamus Barbarus (Orthoptera: Calliptaminae): Contact and Ingestion Effects

This work is a study on the insecticidal effect of aqueous extracts of seeds and leaves of Harmal Peganum harmala on both of two larvae L2 and L3 of barbarian locust Calliptamus barbarus (Orthoptera: Acrididae). GCP analysis revealed the presence of 1 2-benzenedicarboxylic acid, diisooctyl ester as the most frequently constituents found in the plant. Treatments on C. barbarus have been performed by two ways: contact and ingestion. Contact allowed us to obtain a cumulative mortality rate (after 3 days of treatments) which was 90% for a highest dose (2.4 g/l ) with an LD 50 of 0.67 g /l for AqE seeds and 50% of mortality with 3.01g / l for leaves. By ingestion and after 6 days of treatments, the cumulative mortality rate for the dose of 2.4 g/l and the LD 50 of AqE seeds were respectively 90% and 0.45 g /l. For leaves, these were 70% and 0.85 g /l. The comparative effect of contact and ingestion tests between the two “bioactive extract” by their respective LD 50 show that seeds AqE are more effective than leaves. This difference in mortality rate is due mainly to the variation in the contents in the various organs of the plant more important in seeds than leaves. Concerning the modes of action we noted that after 3 days of contact treatment, a result (90%) similar to that recorded 6 days after ingestion treatment is obtained for seeds. This difference in mortality time is interpreted by the faster mode of penetration by contact than by ingestion.