Basil oil, Ocimum basilicum L., is a volatile plant essential oil that is known to have insecticidal activity against stored product pests such as rice weevil, Sitophilus oryzae (L.). Basil oil was diluted in acetone and applied to a sponge held inside a tea strainer for fumigations in containers with and without rice. Basil oil fumigation (3 ml, 10% concentration) caused high mortality in adult rice weevils when weevils were exposed in air in a sealed 1 L plastic container. However, when basil oil was placed in packaged rice, weevil mortality was low and reproduction was not affected. Effectiveness of plant essential oil fumigation should be conducted under realistic conditions to avoid experimental artifacts and misleading results.