© Benaki Phytopathological Institute
Hellenic Plant Protection Journal
91-99, 2009
Sublethal effects of three essential oils on the development,
longevity and fecundity of
Acanthoscelides obtectus
(Coleoptera: Bruchidae)
D.P. Papachristos
and D.C. Stamopoulos
Acanthoscelides obtectus
larvae and pupae were exposed to three levels (LC
, LC
and LC
of lavender, rosemary and eucalyptus essential oil vapours. The exposure of larvae and pupae to sub-
lethal doses of essential oil vapours resulted in increased larval and pupal developmental time and re-
duced longevity and fecundity of the emerged female adults. The observed effects depended on the
insect stage and sex as well as the essential oil tested. In all cases no delayed mortality was observed.
Additional keywords
Eucalyptus globulus, Lavandula hybrida, Rosmarinus officinalis,
Department of Entomology and Agricultural Zoolo-
gy, Benaki Phytopathological Institute, 8 St. Delta Str.,
145 61, Kifissia (Athens) Greece.
Laboratory of Zoology and Aquatic Entomology, De-
partment of Agriculture, Ichthyology and Aquatic En-
vironment, School of Agriculture, University of Thes-
saly, Volos, Greece.
Corresponding author:
Although the insecticide properties of
the aforementioned essential oil vapours
have been well documented and their LC
values were established, their possible sub-
lethal effects have not been thoroughly ex-
plored even though it is well known that
many target insects do not receive the ap-
propriate lethal dose during fumigations. In
fact, insects exposed to sublethal doses of
insecticides may display a variety of symp-
toms including reduction in growth rate,
life span, pupal weight and adult fecundity
and fertility (3, 4, 5, 9, 10, 15). In contrast, ad-
vantageous effects have also been record-
ed; these include increased immature stage
weight, developmental rate and adult fertil-
ity (27). Therefore, the consequences of sub-
lethal exposure have important implications
on insect management and from this point
of view it is worthy to elucidate such type of
effects exhibited by the essential oil vapours
(14). Moreover, as Karr and Coats (13) point-
ed out, when monoterpenoids are investi-
gated as potential insecticides, direct toxici-
ty as well as appraisal of negative effects on
biotic potential must be considered in the
assessment of overall efficacy.
The aim of this study was to investigate
the effects of sublethal doses of lavender,
rosemary and eucalyptus essential oil va-
In recent years, the trend towards reducing
reliance on synthetic insecticides for the con-
trol of stored products pests has oriented
worldwide research in the insecticidal prop-
erties of different essential oils that often be-
have like conventional fumigants exhibiting
strong adverse effects on both immature and
adult stages. In fact, these compounds may
act as fumigants, repellents, antifeedants
and may also affect some biological parame-
ters such as growth rate, life span and repro-
duction (11, 12, 16, 18, 19, 20, 21, 23, 26).
Previous studies (18, 19) have estab-
lished the strong toxic activity of the essen-
tial oil vapours of
Lavandula hybrida
Rev. (La-
Rosmarinus officinalis
L. (Lamiacae)
Eucalyptus globulus
Labill. (Myrtacae)
against the immature stages of
celides obtectus
(Say), the most destructive
pest of
Phaseolus vulgaris
L. (kidney bean),
one of the most important food pulses in
South America and the Mediterranean re-
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