الفهرس 
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Abstract
SUMMA-BY
The onion bulb fly Eumerus amoenu~ Loew. is one of the
main insects which infesting onion crop in Egypt either in
field or in storage. The stored onion bulbs are destroyed
by larvae, and loss in stored crop depends upon population
density.
Using of gamma radiation in controlling insects appears
to have some advantages over other control methods. The
objective of this study was to investigate gamma irradiation
effects on E. amoenus which is considered one of the most
important insects in Egypt.
A.Effect of gamma radiation on different developmental stages:
a- Egg stage:
1- Percentage hatchability of irradiated one and two-dayold
eggs decreased by increasing dose.
2- Percent hatchability of 1 and 2-d-old eggs dropped
to zero at a dose of 10 and 30 Gy. respectively.
3- Increasing of egg irradiation dose decreased percent
pupation and emergence of 1 and 2-d-01d eggs.
4- As a resu1t of egg irradiation, egg-larvae and pupal
duration of 1 and 2-4-01d eggs increased by increasing
doses.
5- Females seemed to be more successful in emergence
than males, when 1 and 2-d-old eggs were irradiated
by different doses.
b- Larval stage:
1- Bgg-larvae duration increased by increasing dose.
2- There was a gradual decrease in percent pupation by
increasing dose.
3- The dose 50 Gy prevented adult emergence of 2-d-old
larvae, while the dose 60 Gy was required to produce
the same effect to fully grown larvae.
4- Females seemed to be more successful in emergence
than males with all radiation doses used.
c- Pupal stage:
1- Gamma radiation reduced fecundity and fertility of
all matings for 1 and 7-d-old pupae.
2- The dose 4.0 and 90 G.r caused complete sterility for
females and males of fu1ly grown pupae. respectively.
3- i’he dose 50 Gy prevented adult emergence of both sexes
of l-d-old pupae, while the dose 90 Gy did not affect
the adult emgergence of 7-d-old pupae.
4- Pupal irradiation caused a slight effect on pupal
duration of I-d-old pupae. and did not affect the
older ones.
5- Percent malformed adults of both sexes of I-d-old
pupae increased at the dose was increased until it
reaches to 100~ at the dose of 20 Gy, while the tested
doses for the older ones gave normal adults.
6- Adult longevity of l-d-old pupae was reduced by
increasing the dose while adult longevity of fully
grown pupae was increased by’increaisng dose.
d- Adult stage:
1- Fecundity and fertility of l-d-old adult reduced by
increasing dose.
2- !he dose 60,150 and 50 Gy caused complete sterility
for females, males and both sexes, respectively.
B. Effect of gamma radiation on mating competitiveness:
l
1- Irradiated males (1) mated with unirradiated males
an females at ratio or 1 : 1 : 1 caused 24.4~egg
hatch.
2- Increasing the ratio to 5 : 1 : 1 and 10 : 1 I 1 caused
11.7 and 2.2 percent hatch, respectively.
3- !be calculated competitiveness values for 3 ratios
were 1.04, 0.6, and 2.2 respectively.
4- Males and females botll treated with a sterilizing dose
ratio caused 68.8% infertility in the resulting eggs.
5- When the ratio of sterile males and females was
increased to 5 : 5 : 1 : 1, 10 : 10 : 1 : 1 and
15 : 15 : 1 : 1 (I ! :I ~ : U t : u ~), the percentage
infertility was 80.9, 92.7 and 100, respectively.
6- The competitiveness values for these flooding ratios
were 0.88, 0.83, 0.93 and 1.00, respectively.