Potential insecticidal effects of Valeriana jatamansi and Isodon rugosus against Acanthoscelides obtectus (Say) (Coleoptera, Chrysomelidae), a pest of Phaseolus vul

Abstract

The insecticidal efficacy of Valeriana jatamansi and Isodon rugosus was evaluated against the bean weevil Acanthoscelides obtectus (Say), a pest of Phaseolus vulgaris L. The rhizome and leaves extracts from V. jatamansi and I. rugosus were prepared by using both acetone and methanol solvents and five concentrations of each extract were evaluated for its effectiveness in inducing adult mortality of the adult weevils. Acetone and methanol extracts of V. jatamansi rhizome and I. rugosus leaves at 12 per cent concentration exhibited 100 per cent mortality of adult bean weevils on the 7th and 8th day, respectively. As the concentration of the extracts escalated from 4 to 12 percent, the death rate also correspondingly increased.