The laboratory experiment was conducted to assess the efficacy of methanol leaf extract of five medicinal plants namely Piper longum, Pongamia pinnata, Murraya koenigii, Acalypha indica and Justica gendarussa at five concentrations (0.025g/ml, 0.75g/ml, 0.125g/ml, 0.175g/ml and 0.225g/ml) on adult mortality and adult emergence against Sitophilus oryzae. The results revealed that a significant (P<0.05) increase in adult mortality and suppression of adult emergence in all concentration after 72 hours of treatment as compared to controls. The order of toxicity on adult weevil as follows A.indica > P.pinnata =M.koenigii =J. gendarussa >P.longum. LD₅₀ values after 72 hours of treatment was found as 0.182 g/ml (A. indica),0.191g/ml ( P.pinnata),0.214g/ml (J. gendarussa) and reduction in adult emergence by all leaf extract at 0.225 g/ml ranged 60 -79%. These results suggest that these plants acted as potential insecticide against rice weevil and cloud be considered in the control of rice weevil.