In Chile, the main Coleopteran species of stored grains are
Sitophilus oryzae
,
S. zeamais, and
S. granarius
. The aim
of this study was to evaluate under laboratory conditions
the contact and fumigant insecticidal activity, as well
as the repellent and antifeedant effects of
Laureliopsis
philippiana (Looser) Schodde essential oil against adults
of
Sitophilus spp. The main compounds identified in this
essential oil were methyleugenol (61.38%) and safrole
(14.76%). Based on the contact bioassay, the highest
toxicity was achieved with the concentration of 4.0% (v/w),
and
S. oryzae was the most susceptible species. Emergence
(F
1) was reduced as the concentration of the essential oil
increased, reaching maximums of 60% in the case of
S.
granarius and
S. oryzae, and 36% in
S. zeamais. Mortality
by fumigant activity was 100% for the three species of
Sitophilus. All of the treatments had a repellent effect. The
highest antifeedant activity (82.9%) was recorded at 4.0%
(v/w) concentration. Concentrations below 2.0% (v/w) did
not affect germination of maize. Based on these results,
L. philippiana essential oil has the potential to control
Sitophilus spp. weevils.
