ASSESSMENT OF FUMIGANT ACTIVITY OF TWO EUCALYPTUS ESSENTIAL OILS AGAINST THE CIGARETTE BEETLE LASIODERMA SERRICORNE F. (COLEOPTERA: ANOBIIDAE)

The cigarette beetle, Lasioderma serricorne (Fabricius), is a common pest of stored foods. It has been documented attacking over 50 different plant and animal sources. Fumigants have been used to control this pest. However, control failures with phosphine have been attributed to resistance development. Thus, there is an urgent need to develop safe alternatives which are low cost, convenient to use and friendly to the environment. In this context, the toxicity of a large number of essential oils and their constituents has been evaluated against a number of stored-product insects.
This work aims to investigate the fumigant toxicity of the essential oils from Eucalyptus oleosa collected from the arboretum of Hajeb Laaoun (Kairoun) and Eucalyptus striaticalyx collected from the arboretum of Sidi Ismail (Sahel) against new emerged adults of Lasioderma serricorne. Eucalyptus leaves were subjected to hydrodistillation using a Clevenger modified apparatus. Adults were exposed to four concentrations ranging from 26.31 to 197.37 µl/L air.
Results showed that the essential oil from E. oleosa was more toxic than E. striaticalyx. The respective LC₅₀ and LC₉₅ values were 20.94 and 122.30 µl/L air against 27.05 and 147.58 µl/L air.
At the lowest concentration (26.31 µl/L air), mortality achieved 58% for E. oleosa against 54% for E. striticalyx after 24 h of exposure. At the highest concentration (197.37 µl/L air), 100% mortality was obtained after 12 and 24 h respectively for E. oleosa and E. striticalyx.