Fumigant toxicity of eseential oil extraeted from orange peel Citrus sinensis (L) on rice weevil Sitophilus oryzae (L).(Col., Curculionidae) and flour beetle Tribolium castaneum (Herbst)(Col: Tenebrionidae)

According to the high damage of stored pests and adverse effect of chemical pesticide research on the use of secondary metabolites and essential oil of plants are necessary for controlling stored product pest. In this research have been investigated the fumigant toxicity and persistency of essential oil of orange peel Citrus sinensis (L) on rice weevil Sitophilus oryzae L. and flour beetle Tribolium castaneum Herbst. have been investigated The experiment was conducted in a completely randomized design. Essential oil of orange peel was extracted by Clevenger apparatus. The bioassay was done in 40 ml glass Jar at 25±2 °C and 65±5% R. H. under dark condition. Filter paper was used as the sources of evaporating facility. Based on data the LC50 values were 264.25 and 171.45μl/Lair on S. oryzae and T. castaneum at 48 h post- treatments respectively. The persistency of the essential oil on flour beetle (25 days) was significantly more than on the rice weevil (21 days). The LT50 and LT90 were 12.56 and 8.68 days on rice weevil and 15.37 and 11.5 days on flour beetle, respectively. The results showed that the toxicity and persistency of essential oil of orange peel on these pests was acceptable and this oil can be further investigations might be an alternative to chemical pesticides on these product pests.