The effect of the sublethal concentrations of acetone extract
of Piper cubeba fruits ,acetone and petroleum ether extracts of
Thymus vulgaris flowering buds ,malathion and pirimiphos-methyl
on some biological aspects of T castaneum survivors was studied
in the laboratory at 30 ± 2°C and 70 ± 5% R. H.
The results showed that all treatments decreased
significantly the number of eggs laid daily per femal during two
weeks by 64.6, 51.2, 32.5, 39.0 and 27.8 % for the a
forementioned treatments, respectively. On the other hand, no
significant differences were achieved between all treatments and
control for eggs hatchability, duration of pupal stage and sex ratio.
The preoviposition period was prolonged significantly with P.
cubeba acetone extract., while, it decreased obviously with Thymus
vulgar/s acetone extract. The incubation period of eggs was
increased significantly with P. cubeba, but it reduced significantly
with Thymus vulgaris petroleum ether extract. Duration of larval
stage and total developmental period of immature stages were
significantly decreased by using the sublethal concentrations of T
vulgaris acetone extract, malathion and pirimiphos-methyl.