The indiscriminate use of synthetic pesticides has given rise to many serious problems,including toxicity to nontarget organisms, development of pest resistance and resurgence and environmentalcontamination. So during past three decades, the scientists have looked for less persistent and biodegradablealternatives. Essential oils from aromatic plants are recognized as proper alternatives. In this experiment,toxicity of
Zingiber officinale
(Roscoe) essential oil that was isolated via hydrodistillation was investigatedagainst adults of the red flour beetle,
Tribolium castaneum
(Herbst) and larvae of the Mediterranean flour moth,
Ephestia kuehniella
(Zell.) and Indianmeal moth,
Plodia interpunctella
(Hübner). Repellency of this oilon all the three pest species adults was also studied. In determination of fumigant toxicity, the LC
50
value for
T.castaneum
was calculated 374.95
µ
L/L air after 48 hr of exposure. As well, LC
50
for
E.
kuehniella
and
P.interpunctella
after 9 hr were calculated 258.95 and 69.05
µ
L/L air, respectively. In contact toxicity
assay,LC
50
value for
E.
kuehniella
and
P. interpunctella
were determined as 0.61 and 0.81
µ
L/cm
2
, respectively.Relationship between exposure time and oil concentration on mortality of all species indicated that mortalitywas increased by increasing of the oil concentration and exposure time. Repellency of this oil on all the insectspecies was significant