Insecticidal activity of Xylopia aethiopica (Family; Annonaceae) against Callosobruchus maculatus (F) (Coleoptera: Bruchidae) and Sitophilus oryzae (Coleoptera: Curculionidae)

Abstract

The efficacy of Xylopia aethiopica leaf dust and extract on Callosobruchus maculatus and Sitophilus oryzae was evaluated at different doses (1.0 – 3.0 g and 50.0-100 mg-ml) with 10 unsexed adult weevils per 10 gram of substrate per replicate. All treatments were triplicated and mortality of the insects was recorded after every 24 hours (h) for 96 h exposure to powder and extract respectively. The parameter compared was the mortality rate of the adult pests. The negropepper was an active biopesticide against C. maculatus and S. oryzae. However, the plant products gave higher mortality on S. oryzae with a mean of mean mortality and LD50 of 82.2% and 1.06g respectively than on C. maculatus whose mean mortality and LD50 was 79.9% and 1.12g respectively over 96 hours exposure. Statistical analysis showed a significant difference (P<0.05) in pest mortality between treated and control samples. The results suggested that X. aethiopica is more promising botanical insecticides on S. oryzae than C. maculatus.