Disrupted survival, growth and development of desert locust Schistocerca gregaria (Forskal) (Orthoptera Acrididae) by extracts from Toothpick weed Ammi visnaga Lamarck (Apiaceae)

摘要

The present study aims to investigate the survival, growth and developmental effects of Ammi visnaga fruit extracts on the destructive desert locust Schistocerca gregaria . Treatment of penultimate instar nymphs with the highest concentration of ethanol, petroleum ether and n - butanol extracts resulted in 50, 70 and 60% nymphicidal activity, respectively. Also, the successfully moulted last instar nymphs suffered a l ethal action of all extracts. LC 50 values were 21.0, 12.0 and 22.5% of ethanol extract, petroleum ether extract and n - butanol extract, respectively. After treatment of last instar nymph, a dose - dependent course of the nymphicidal activity could not be dete cted after treatment with ethanol extract but with petroleum ether extract or n - butanol extract. LC 50 values 22.3, 20.8 and 22.0% of ethanol extract, petroleum ether extract and n - butanol extract, respectively. With regard to the growth and development, tr eatment of penultimate instar nymphs with ethanol extract and petroleum ether extract led to pronouncedly prohibited growth. All extracts affected the development. No nymphal - adult intermediates had been formed by ethanol extract or n - butanol extract at 40 % concentration. In addition, suppressed developmental rate was caused by ethanol extract but not by other extracts. All A. visnaga extracts prohibited the adult emergence in no certain trend.