Effects of Aqueous Extracts of Seeds of Peganum harmala L. (zygophyllaceae) on 5th Stage Larvae Locusta migratoria cinerascens (Fabricius, 1781) (Orthoptera: Oedipodinae)

Abstract

Abstract:The study has for objective the determination of the efficiency of the aqueous extracts from seeds of Peganum harmala L. on the mortality of the larvas of 5th stage and on the fertility of the female adults of Locusta migratoria cinerascens. For that purpose, a breeding of lo custs was realized in th e conditions of labor atories. At hatching, the larvae are fed daily basis lawn Stenotaphrum americanum and a pro tein supplement of wheat b ran. The extraction of the aqueous extract of the seeds of P. harmala is done after maceration in the ethanol, under magnetic stirring using a rotavapor. To determine larval mortality L5, two modes of treatment have been made, one by contact and another by ingestion, using for bo th treatment 4 doses in a g eometric progression, 0.03 mg/mL, 0.06 mg/mL, 0.12 mg/mL and 24 mg/mL. Th e results showed that the mortality for the doses of 0 .12 mg/mL and 0.24 mg/mL, reaches respectively 40% and 60% on the 3rd day, as well for the treatment by contact as by ingestion. But the LD50 for ingestion treatment is lower. It is 0.19 mg/mL contrary to that of the contact treatment (0.19 mg/mL). The larvae that survived the treatment by ingestion, have suffered morphological changes as well as physiological which consist of a deformation of the wings, delayed of the larval molt, of 6 day s, b locking the fledg ing, the ch ange of the pigmentatio n as well as an extension of the preoviposition. Fertility was a lso affected and females lay only twice, a small number of eggs, unlike untreated females which come to lay 3 times with an average of 62.7 eggs/female at first spawning against 50 eggs for the females treated.