Assessment of the Commercial Botanical Insecticides Against the desert Locust, Schistocerca gregaria (FORSK.) (Orthoptera: Acrididae)

Abstract

Desert locust, Schistocerca gregaria is a serious agricultural pest that causes considerable damage to food crops and pasture grasses . This study was carried out to evaluate the commercial botanical insecticides, Sabadilla, Limonene, Rotenone, and Azadirachtin on Sch. gregaria . Results indicated that the 4 th nymphal instars were affected after feeding on clover leaves treated with the various concentrations of the tested compounds. Early 24hrs. moulted 4th nymphal instar was more sensitive to azadirachtin followed by rotenone, sabadill and finally limonene botanical. The recorded LC 50 value was 3.4, 3.7, 3.9 and 4.2% by the effect of azadirachtin, rotenone, sabadilla and limonene respectively against 4 th nymphal instars 72hrs. post-treatment. While LC90 was 15.2, 18.7, 26.3 and 28.1% in the same previous compound respectively. The higher prolongation of nymphal duration was 17.6 days with azadirachtin at a concentration of 15% and lower prolongation was 10.5 with limonene at a concentration of 5% compared to 10.2 days of control. Also, nymphs suffered from weight loss for all tested botanical insecticides particularly at higher concentrations then died. The morphogenetic effect was obtained at different concentrations of the tested botanical insecticides. Deformation was in the form of abnormal nymphs and nymphal-adult intermediate stages.