Abstract: To assess the insecticidal activity of eucalyptus oil and α-pinene against dried fish pest Dermestes maculates. Mortalities of its larvae and adults under different doses or treatment time were investigated by bioassay method. The results showed that the tested oil and its active ingredient (α-pinene) affected significantly (P<0.001) on the mortality of both the larvae and adults of D. maculatus. Responses varied with compound, dose and exposure time. Over 90% mortality at 72 h after treatment was achieved with the eucalyptus oil against larvae at a dose of 32 μL/cm³. Eucalyptus oil at 32 μL/cm³, were highly toxic to adults of D. maculatus 72 h after treatment. α-Pinene also showed highly toxic effects on both larvae and adults of the beetles at the same exposure time and doses. It is also interesting to mention that the adults of D. maculatus were found to be more tolerant than larvae. In probit test eucalyptus oil was much more effective than α-pinene. These naturally occurring materials could be useful for managing populations of D. maculatus.

Key words: Eucalyptus oil, α-pinene, fumigation, adults, larvae, dried fish