Influenced survival and development of the desert locust Schistocerca gregaria (acrididae) by the wild plant Fagonia bruguieri (zygophyllaceae).

Abstract

Three extracts were prepared from the wild plant Fagonia bruguieri: methanolic extract, petroleum ether extract and n-butanolic extract. These extracts were assessed against the penultimate and last instar nymphs of Schistocerca gregaria. After treatment of the penultimate instar nymphs, a dose-dependent trend of mortality could be observed for the methanolic extract. To some extent, a lesser toxic action was exerted on the nymphs by petroleum ether extract or n-butanolic extract. After treatment of the last instar nymphs, an ascending mortality % was estimated as the concentration level of methanolic extract was increased. After treatment of the penultimate instar nymphs, the growth of the same treated nymphs was affected to some extent by the methanolic extract, irrespective of the concentration level. The remarkably influenced nymphal growth was detected only at the highest concentration level of petroleum ether extract and the higher two concentration levels of n-butanolic extract. Also, the profoundly extended developmental duration was caused by petroleum ether extract at the higher three concentration levels. After treatment of the last instar nymphs, all extracts exhibited inhibitory effects on the growth because the nymphs were prohibited to gain somatic weights as their control congeners obtained. A fastening action of methanolic extract on the developmental rate along shortened developmental duration especially at the highest concentration level. In contrast, a retarding action on such rate of the developing nymphs was exerted by both the petroleum ether extract and n-butanolic extract. The Fagonia bruguieri extracts intervened in the metamorphosis program because some nymphal-adult intermediates were formed.