The efficacy of powders of Eugenia aromatica, Piper guineense and Zingibar officinales as an entomocide against Sitophilus oryzae infesting rice grains was investigated at ambient temperature (30°2 °C) and relative humidity (74°4%). Weevils were exposed to different doses (0.10-2.00g/10g of rice grains) of each plant material and mortality was assessed at 24, 48, 72 and 96 hours post-treatment respectively. The result showed that weevil mortality increased with increasing doses of plant materials and exposure time. However, E. aromatica was the only plant material that elicited complete weevil mortality (100%) after 72 h at 2.0g/10g of rice while Z. officinales evoked less than 40% weevil mortality irrespective of the exposure time. LT50 values showed that weevil exposed to E. aromatica powder required the lowest time (1.63-1.06 h) while their counterpart exposed to P. guineense (3.98-1.07 h) and Z. officinales (15.18-9.75 h) showed the median and highest Lethal time (LT50) respectively. Based on LT50 values, the order of toxicity of plant materials to S. oryzae from highest to lowest is: E. aromatica > P. guineense > Z. officinales. This study shows that powders of E. aromatica and P. guineense could serve as an alternative wherewithal to synthetic insecticides in controlling S. oryzae infesting rice.