Abstract:
Diatomaceous Earth (DE) is a dust composed of fossi
lized bodies of unicellular algae
used as an insecticide. In this study, the insectic
idal potential of four Iranian DE deposits
was assessed in adults of
Oryzaephilus surinamensis
(L.)
.
Three of DE deposits were
collected from Maragheh, Mamaghan, and Khorasan Jon
oobi mines and Sayan
®
formulation was obtained from Kimia Sabz Avar Compa
ny. The insect adults were
exposed on wheat, peeled barley, and rice treated w
ith 300, 600, 1,000, 1,500, and 2,000
ppm of the DE deposits. Experiments were conducted
at 27
±
1°C
and 55
±
5% RH in
continuous darkness. Mortality of the exposed indiv
iduals was counted after 2, 5, 10, and
14 days of exposure on the treated substrate. Morta
lity increased with increasing
exposure intervals and concentration level. Satisfa
ctory level of protection was observed
on wheat grain; as 100% mortality was recorded on w
heat
treated with 600 ppm of all
tested DE deposits after a 10-day exposure. However
, for rice, even after 10 days of
exposure to 2000 ppm mortality didn’t reach 100%. T
he lowest
LC
50
value (39 ppm) was
obtained in wheat treated with Khorasan DE sample a
nd the highest one (908 ppm) was
achieved in rice treated with Sayan
®
. The present study suggests that Iranian DEs may b
e
used as potential grain protectants in stored-produ
ct pest management programs.
Keywords:
Barley storage, Pest management, Rice storage, Stor
ed grain protectant, Wheat storage.
