| Abstrakt: |
AbstractAcetone and chloroform extracts of the seed of Xylopia aethiopica(Dunal) A. Rich (Annonaceae) were evaluated in the laboratory for their insecticidal effect on the adult Callosobruchus maculatus(Fabricius) (Coleoptera: Bruchidae). Adult mortality was assayed using 0.5ml and 1.0 ml of extract per 20 g cowpea. Five dosages (0.2, 0.4, 0.6, 0.8 and 1.0 ml) of X. aethiopicaextracts per 20 g cowpea seed were used to determine the oviposition, adult emergence and seed damage by C. maculatus. Untreated control and solventtreated control were included. At 3 and 5 days after treatment (DAT),percentage mortality was significantly (p<0.05) higher in cowpea treated with chloroform extract (46.53%, and 62.45%, respectively) than what obtained in acetone extract (34.2% and 52.43%, respectively) of X. aethiopica. Application of extract at 1.0 ml/20 g seed caused significantly (p<0.05) higher percentage mortality when compared with the solvent treated controls. The LD50(0.42 and 0.02 ml/20 g seed) for chloroform extract at 3 and 5 DAT were smaller than values for acetone (0.78 and 0.17 ml/20 g seed) at the same duration after exposure, respectively. LT for acetone and chloroform extract was 2.21 and 1.76 h, respectively. The number of eggs laid on cowpea treated with 1.0 ml/ 20 g seed was significantly (p<0.05) lower than the number of eggs laid on the solvent-treated control and seeds treated with 0.2 ml/ 20 g. Percentage seed damaged significantly (p<0.05) decreased with increased concentration, while the highest damage was obtained in solvent-treated cowpea seeds. |
