Abstract:
In laboratory experiments the toxicity of
acetone was investigated
against four species
of stored-product insects. In empty-space trials, estimates of the lethal concentrations of
acetone (LC
,
72-h exposure) for 50% mortality against adults of the lesser grain borer,
Rhizopertha dominica
(F.), red flour beetle,
Tribolium castaneum
(Herbst), rice weevil,
Si-
tophilus oryzae
(L.) and eggs of the angoumois grain moth,
Sitotroga cerealella
(L.) were
33.64, 41.05, 43.90 and 46.11 μl/liter, respectively. At the LC
95
level, the order of sensitiv-
ity was rated to be:
R. dominica
adults >
S. oryzae
adults >
T. castaneum
adults >
S. ce-
realella
eggs. Penetration tests revealed that
acetone vapour could penetrate into the
wheat mass and kill concealed insects in
interkernel spaces.
Comparison of LC
50
values
between empty-space tests and penetration
experiments (after 72-h exposure) indicated
that the increase in penetration t
oxicity was 8.52- and 8.09- fold for
R. dominica
and
T.
castaneum,
respectively. A similar trend was observed at the LC
95
level.
In the hidden in-
festation trial, the acetone vapour destroyed all the developmental stages of
S. oryzae
con-
cealed inside the wheat kernels and resulted in a complete control with a concentration of
320 μl/liter for 8 weeks after the exposure. Base
d on the data collected in this study, ace-
tone should be considered as a potential compound for empty space fumigations. How-
ever, due to its sorption characteristics and
the application of high doses, acetone may
have only limited use as a fumi
gant under practical conditions
