Insecticidal effects of stick formulation of five medicine plants essential oils against sawtoothed grain beetle, Oryzaephilus surinamensis and the khapra beetle, Trogoderma granarium

Essential oils of some plant species have shown suitable insecticidal properties against stored-product pests, which are one of the main factorsaffectingpost-harvestfoodlosses. In this study mortality, repellent effects and durability of fumigant toxicity of the formulated essential oils of golpar (Heracleum persicum), thyme (Thymus vulgaris), eucalyptus (Eucalyptus globules), peppermint (Mentha piperita) and rosageranium (Pelargonium roseum) as 2.5 gr sticks (10%), were studied on two important pests of stored products, Oryzaephilus surinamensis and Trogoderma granarium in laboratory at 28 ± 1 °C, 70 ± 5 % RH and dark condition. The results showed that sticks of rosageranium and golpar had the lowest toxicity and sticks of peppermint and thyme had the highest toxicity effects especially on O. surinamensis. The highest repellency effect was observed in peppermint and eucalyptus on O. surinamensis (94 and 91/6 % respectively) while repellency of rosageranium sticks was observed below 20% on both pests. Sticks durability in comparison with pure essential oils of plants was significantly different so that from the fourth day by the end of the eighth week the mortality rate was approximately constant while the durability of pure essential oils decreased after 2-3 weeks represents the slow-releasing of essential oils in stick formulation.