ABSTRACT
Telfairia occidentalis, Piper guineensis, Gmelina arborea, Bryophyllum pinnate, Amaranthus viridis, and Musanga ceropolides were separately assessed for insecticidal effects on Acanthoscelides obtectus Say, a pest of stored Phaseolus lunatus L. The plants were assessed in a completely randomized design for aduticidal and reproductive inhibition potential as well as effect on seed weight at three treatment doses (2%, 4%, 6% and 0 as the control). Results showed that at 144 hours post-treatment, P. guineensis at 6% dose had the highest significant (P=0.05) mortality (59.5%) of A. obtectus. This was followed by P. guineensis which had comparable effect 2% (50.9%) and 45 (54.9%). The least significant mortality was observed in control. At 4% and 6% A. viridis had similar mortality effect on A. obtectus as 6% G. arborea, while 2% A. viridis, 6% B. pinnate, 2% and 4% G. arborea had similar effect. The highest number of progeny emerged after 49 days were observed in control (345.33±8.84) while P. guineensis significantly (P=0.05) inhibited progeny followed by 6% G. arborea and 6% M. ceropolides. Phaseolus lunatus seeds treated with 6% P. guineensis also had the least significant weight loss while the control had the greatest weight loss of 32.56 g. Though all these test plants significantly (P=0.05) increased adult mortality, reduced progeny emergence and weight loss in seeds than the control. Piper guineensis however, exhibited the best insecticidal property. Piper guineensis and G. arborea were significantly more active in inhibiting A. obtectus reproduction and progeny emergence, but increased adult mortality leading to reduction in weight loss.