الفهرس 
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Abstract
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STIMMARY
Experiments were carried out to investigate the
difference in susceptibility between field collected
samples of s. li~toralis and their first filial generation.
Results showed the absence of any significant
difference in their susceptibility to monocrotofos,
profenofos and chlorpyrifos.
Day to day variations in a laboratory culture
were investigated, results revealed that the differences
observed were of no statistical significance. Insecticides
used were chlorpyrifos, profenofos, monocrotofos,
DDT and cypermethrin. Susceptibilities of adult female
and male moths of ~. littoralis were determined
in comparison with 41a instar larvae. Results revealed
that females were more susceptible than males to
profenofos, monocrotofos and DDT. In chlorpyrifos
and cypermethrin there were no significant differences.
Both male and female adults were found to be significantly
less susceptible to the insecticides investigated
than 4!h iostar larvae.
Field samples were collected from Sharkia.
Gharbia and Dakahlia governorates in early and late
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seasons of 1980 and their Fl compared to
a laboratory culture for their susceptibility to monocrotofos.
chlorpyrifos. and profenofos. No significant
differences in the early season were detected
in the susceptibilities of field samples and laboratory
culture. In the late season. however, field samples
from the three governorates were found to be significantly
less susceptible to chlorpyrifos. No significant
differences in susceptibilities were observed between
late and early season field samples except in the
case of Dakahlia and chlorpyrifos.
In 1982, field s&aples were collected from the
same governorates and their susceptibilities compared
to a laboratory culture for monocrotofos, chlorpyrifos,
profenofos. DDT, and cypermethrin in both early
and late seasons. Results indicated no significant
differences between early and late seasons except
in Gharbia where profenofos was significantly less
effective in the late season than the early, the
same was found with DDT in Sharkia. In cypermethrin,
Gharbia and Dakahlia samples showed low susceptibility
in the late season, the difference was significant.
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Dakahlia samples were significantly less susceptible
to profenofos in both the early and late
season than the lab. culture. Chlorpyrifos was
significantly less effective to l::1ltlhe field samples
than the laboratory culture in both early and
late season.
Monocrotofos did not show any significant difference
between field and laboratory samples, while
DDT field samples from Sharkia and Gharbia were significantly
less susceptible than laboratory culture
in the early season samples. In the late season,
however, all field samples were significantly less
susceptible than the laboratory culture.
The effect of exposure of 4th instar larvae to
a dose producing c.a. 20 % mortalities produced no
significant effect on further development except in
monocrotofos, where the number of treated larvae
reaching 6!h instar was significantly reduced. When
adults were similarly exposed, there was a significant
reduction in oviposition with monocrotofos.
DDT and cyper.methrin. A drastic reduction in the
hatchability was obtained in the laid eggs from
females treated with the five insecticides investigated.