Fumigant toxicity of 53 Iranian Eucalyptus essential oils against stored product insect, Sitophilus oryzae L.

Although Eucalyptus is native to Australia but, many Eucalyptus species have been introduced to other parts of the world such as Iran and there are about 53 Eucalyptus species in the north and south of Iran. Eucalyptus trees have economic importance in Iran and they are planted as economic and ornamental trees in forest trial provenances. Eucalyptus trees are also an important source of essential oils. In view of the biological applications of Eucalyptus essential oils, this investigation has been carried out on the insecticide activity of the oils and, essential oils extracted from the 53 Eucalyptus species were screened for toxicity effects against the stored product insect, Sitophilus oryzae (L.). All of the essential oils from the 53 Eucalyptus species showed fumigant toxicity against S. oryzae. However, the fumigant toxicity (LC50 value) was variable and in the range from 22.87 to 59.12 µl/l air. Among all examined Eucalyptus essential oils, the essential oils from E. camaldulensis, E. globulus, E. flocktoniae, E. fraxinoides, E. stricklandii, and E. macarthurii had the highest fumigant toxicity (LC50