A study to determine the effect of essential oils, used together with mixed packaging, on controlling stored-grain insects, was conducted in the laboratory. Plant essential oils are one of the materials that act like a contact-fumigant, offering the prospect for use in stored product protection. Plant essential oils must have the ability to repel the insects in order to prevent penetration to foodstuffs. The objective of the present study was to test the properties of Cinnamomum camphora and Syzygium aromaticum for preventing the penetration of pest insects, including: Sitotroga cerealella and Ephestia kuehniella 5th instar larvae to packaged cereals. Ten grams of wheat and flour as foodstuffs were placed inside Cellophane packages and hung vertically in the top of a container. The repellent essential oils were used in the interior surface of containers. Each container had punctures at different parts and the insects were released around the container to determine insect penetration and the effect of the repellents. The experiments were conducted at 26±1°C, 60±5% RH in dark conditions. The highest concentration was 1.5 µl of essential oil per 0.5 ml acetone. Four days after the initiation of the experiment the results showed S. aromaticum had more of a repellency effect than C. camphora on both pests that caused contamination deduction inside the packaged foodstuffs compared with the control. However, both the essential oils were effective as protectants of cereals but S. aromaticum was more effective. S. aromaticum caused the most repellency on E. kuehniella. The mean of repellency of all the concentrations was 81.4%. The results demonstrated the efficacy of these essential oils for use in organic food protection. C. camphora and S. aromaticum can prevent warehouse infestation of stored-product pests.
