Efficiency of Zingiber officinale and Myrtus communis extracts against Red flour beetle, Tribolium castaneum

Continues use of synthetic insecticides has resulted in many serious problems, such as the development of insect resistance, toxicity to non-target organisms and environmental pollution. Thus, there is a necessity for effective and safe alternatives which can control stored grain pests infestation. This study was conducted to evaluate the insecticidal activity of two plant extracts, ginger, Zingiber officinale and myrtle, Myrtus communis separately and in combination against adult of red flour beetle, Tribolium castaneum. The plant extracts prepared by using Soxhlet Extractor and Ethyl alcohol as solvent. Three concentrations (2.5%, 5%, and 7.5%) of each plant were prepared. We placed 0.5 mL of each concentration on filter paper in petri dish, in addition to the control treatment. Ten adult insects were put into each petri dish. The mortality rate was recorded at 24, 48 and 72 h after treatment. The results indicated that the mortality was varying from plant to plant as flowing: M. communis reached its maximum value of 3.33% at 7.5 g mL-1 after 72 h. In the case of Z. officinale, it was 4% at 7.5 g mL-1 after 72 h, while the mixture of Z. officinale and M. communis reached its maximum value (4%) at 7.5 g mL-1 after 48 h exposure time. Relationship between exposure time and concentrations on mortality of T. castaneum indicated that mortality was increased by elevating the concentration and exposure time. The results of the present study revealed that by considering the mean mortality as a main index, the combination of Z. officinale and M. communis was the most toxic, while M. communis the least toxic. Results suggested that the combination of the two extracts could become interesting alternative to conventional chemical insecticides against stored grain pests.