The lesser grain borer, Rhyzopertha dominica is a major insect pests of stored grain in the tropics. Vegetable oils (chamomile, sweet almond and coconut) at 2.5, 3.5, 5.0,7.0 and 10.0 mL/kg were tested against Rhyzopertha dominica (F.) in wheat grain. All bioassays were conducted at 30℃ and 65% ± 2% RH. Treatments with vegetable oils at high dose (10.0 mL/kg) achieved over 95% control within 24 h of exposure to freshly treated grain.There was little difference between the three oils in their effect. Persistence of oils in grains was tested at short-term storage intervals (48, 72 and 96 h) and intermediate-term intervals (10, 20 and 30 days) after treatments. The activity of all products decreased with storage period. Seed viability was reduced by the high dose rate (10.0 mL/kg) ofoil treatments. The potential use of vegetable oils as supplementary or alteative grain protectants against insect damage in traditional grain storage in developing countries is discussed.