In this study, the pruning residues of ficus benjamina tree were used to prepare the wood vinegar through the carbonization process then its effectiveness was evaluated against the rice weevil Sitophilus oryzae (L.) (Coleoptera: Curculionidae) as single treatment by two bioassay techniques; contact and fumigation, then mixed with the sublethal dose of deltamethrin (LC₂₀) and re-evaluated using the contact technique. The GC-MS analysis was used to analyze the chemical composition of wood vinegar. The wood vinegar did not have insecticidal activity although it reached the highest concentration (100%), while after mixing with LC₂₀ of deltamethrin, the toxicity of both was greatly increased, when a low concentration of wood vinegar (5%) mixed with LC₂₀ of deltamethrin, the mortality reached about 90%. The GC-MS analysis showed that the phenolic compounds were the major component in the wood vinegar followed by the benzene derivatives. The obtained results clearly showed the ability to use the wood vinegar as a natural compound mixed with chemical insecticides successfully so that we can reduce the concentrations of chemical insecticides involved in our environment.