Efficacy of Chamomile, Sweet Almond and Coconut Oils as Post-harvest Grain Protectants of Stored Wheat against Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae)

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, 7 and 10 ml/kg were tested against Rhyzopertha dominica (F.) in wheat grain. All bio-assays were conducted at 30C. Treatments with vegetable oils at high dose (10 ml/kg) achieving over 95% control within 24 h of exposure to freshly treated grain. There was a little difference between the three oils in their effect. Persistence of oils in grains were tested at short-term storage time (48, 72 and 96h) and intermediate-term (10, 20 and 30 days) after treatments. The activity of all products decreased with storage period. Seed viability was reduced by the high dose (10 ml/kg) of oils treatments.