الفهرس 
IntroductionOnly 14 pages are availabe for public view
Abstract
Excessive use of insecticides has not only developed
resistance against the insecticides but has also yielded a series of
unbearable problems, on human health concerns like residues in food
chain, environmental pollution and soil degradation.
Recently, due to the negative impacts of pesticides, attention
has been focused on adopting integrated pest management (IPM)
strategies, which include physical and biological control methods as a
viable option of managing pest insects. These methods include the
use of resistance crop varieties, insect growth regulators,
pheromones, behavior modifying chemicals, biological control agents
and natural products.
Management with biocontrol agents is the most appreciated
method for environmental safety. Among the various groups of
biocontrol agents, Braconid parasitoids are well known for the
management of different pests.
B. brevicornis is an important potential biological control
agent. It is an ectoparasitoid that attacks larvae Coleoptera, Diptera
and of several species of Lepidoptera, mainly pyralid moths.
The present work was carried out under laboratory condition
to study some biological aspects of B. brevicornis under different
experimental conditions.
The following synopsis, emphasis the main findings of this
study conclusion are briefly summarized: Survey:
This work seeks to survey insect populations on certain plant
crops at three governorates (Giza, Qaliubeia and Assiut) in Egypt.
In this respect, we recorded Bracon spp. on the tomatoes
plants crops associated with Tuta absoluta in the three governorates.
Giza governorate: In 2011, population of Bracon spp. was
recorded in September higher than that recorded in April, August and
April. On other hand in 2012 Bracon spp. was higher in August than
that recorded in September. While Bracon spp. was recorded only in
January 2013.
Qaliubeia governorate: Bracon spp. was recorded in
September 2011 lowest than that was in August. During 2012
Bracon spp. recorded only in September while in 2013 we do not
recoded Bracon spp.
Assiut governorate: During 2011 Bracon spp. was recorded
in October higher than that in September and recorded only in
September during 2012. While there was no recorded in 2013.
2. Morphological and molecular genetics identification:
A. Morphological identification:
from our observation we found that, the adults of B.
brevicornis and B. hebetor cannot be easily distinguished and cannot
depend only on morphological characters to differentiate between the
two species of Bracon. The colour of adult parasitoids was variable
among both species. And the mean number of antennal segments were (15.2±0.42453 and 13±0.00 segments) for female B. hebetor
and B. brevicornis respectively, While the mean number of antennal
segments of male B. hebetor and B. brevicornis were
(18.5667±0.18372 and 20.8667±0.19018 segments) respectively.
B. Molecular genetics identification:
Random amplified polymorphic DNA (RAPD)-PCR genomic
fingerprinting and partial sequencing of the 16S rRNA gene were
evaluated on two insects collected from the Egyptian field which
could belong to B. hebetor and B. brevicornis to investigate their
genetic relatedness and to establish the value of techniques for their
identification. Nearly identical RAPD-PCR profiles and identical 467
bp fragments of the 16S rRNA genes indicated many of genetic
diversity between the two insects under study. The low levels of
similarity (78.21% in the partial 16S rRNA genes and 86% in RAPDPCR)
appeared between the insects B. hebetor Egypt and B.
brevicornis Egypt. However, 16S rRNA genes and RAPD-PCR
provided an effective means of differentiating between members of
the taxa. Moreover, a phylogenetic tree constructed from 16S rDNA
sequences showed that B. hebetor Egypt clustered with the B. hebetor
with a degree of similarity 92%, but B. brevicornis Egypt clustered in
a separated group. However, RAPD-PCR and partial sequencing of
the 16S rDNA analysis raises questions about the taxonomic
positioning of the two insects isolated from the Egyptian
environment.
3. Biological studies of Bracon brevicornis :
I. Rearing of B. brevicornis on different host larvae:
We studied the biological aspects of the parasitoid when we
reared it on different hosts (Ephestia kuehniella, Galleria mellonella,
Corcera cephalonica, Sesamia cretica, Spodoptera littoralis and
Pectinophora gossypiella).
Our results assured that, the type of host had great impact on
the durations of the immature stages and longevity of the parasitoid.
1-Incubation period:
The highest and lowest incubation periods were when reared
the parasitoids on on P. gossypiella (45.75±1.4hours) and E.
kuehniella (39.87±0.95 hours) respectively the difference was
insignificant at the other hosts.
2- Larval stage:
Duration of larval stages was significant shorter when
parasitoid reared on S. cretica (1.86±0.079 days) than the rest hosts.
3- Pupal stage:
The longer pupation period was recorded when parasitoid was
reared on P. gossypiella (7.6±0.13 days).But was insignificant on the
other hosts.
4- Immature stage:
The highest duration period of immature stage was
when we reared B. brevicornis on P. gossypiella (12.75±0.74 days) but insignificant difference when we reared it on G. mellonella
[9.16±0.22 days], and S. cretica [9.91±0.14 days].
5-Adult stage:
A. Male longevity:
The mean duration of male longevity of parasitoids was
longer when reared on E. kuehniella (15.73±0.73 days) and was
shorter when reared on C. cephalonica (11.75±0.51 days).
B. Female longevity:
The mean duration of female parasitoids was highest when
we reared parasitoids on S. cretica (19.6±0.51 days).
The total number of eggs laid per female of B. brevicornis
during its life span was highest on Galleria mellonella (268.88±19.65
eggs), and lowest on C. cephalonica (78.1±10.63 eggs).
A percentage of hatchability was significantly lowest when
we reared B. brevicornis on S. littoralis (0.09±0.02642 %) than when
reared on the other hosts. Percentage of emergence was
insignificantly different when reared on Sesamia cretica
(87.36±3.92%) and P. gossypiella (87.02±3.85%).
II. Effect of (parasitoid and host) densities on deposited eggs
of B. brevicornis:
1. Parasitoid densities:
The data indicate that, the highest number of deposited eggs
was synchronizing with the increase of female parasitoid density.
where the total number of eggs per day increased from 12.5±2.18eggs at 1wasp densities to 31.80±2.6 eggs at 8 wasp
densities
2. Host densities:
The minimum number of eggs deposited under higher density
of larval host, the mean number of eggs per day decreased from
14.30±1.78 to 11.43± 0.19 when the density increased from 1 to 32
hosts.
4. Functional response of B. brevicornis to different
densities of G. mellonella:
The functional responses of B. brevicornis to different
densities of G. mellonella could be described very well by Holling
disc equation II, where the average number of hosts attacked by adult
parasitiod increased with host density during 24 h period and the
proportion of host attacked by parasitoid declined with increasing
host density, from 1 at the density of 1to 0.55625 at the density of 32
larvae.
Rate of attack (a) and handling time (Th) were 1.03 and
0.6672 hours, respectively. The expected maximum number attacked
host T/ Th is 35.97 hosts per day.
5. Entomopathogenic fungi:
In this work we studied the effects of the Metarhizium anisoplia
and Beauvaria bassiana on B. brevicornis in the laboratory to
evaluate the possibility of application of entomopathogenic fungi and
the parasitoid B. brevicornis side by side in IPM programs.
A. Metarhizium anisoplia:
No mortality observed at the highest concentration (4g/L) and the
lowest tested concentration while the recommended concentration
recorded mortality (0.133±0.091%) of B. brevicornis adult.
B. Beauvaria bassiana:
The recommended concentration (2g/L) induced no mortality
among the adult parasitoids while the highest tested concentration
(4g/L) and the lowest concentration (1g/L) gave mortality
(0.067±.0667%) and (0.133±0.091%) respectively.
6. Rearing of B. brevicornis on artificial diets:
The parasitoid failed to complete their life on semi artificial diets,
Diet 1 (E. kuehniella pupal holotissue 40%, egg yolk 20%, low-fat
milk 20%, and distilled water10%, mixture of Neisenheimer’s salt
10% and antibiotic solution 0.6%) Diet 2 (Hemolymph Galleria
mellonella larva 50%e, egg yolk 25% , dry milk reconstituted with
water 25% and gentamicin solution 1%) where most of eggs shrank
and little hatchability of eggs was recorded on both semi artificial
diets, even this hatched larvae died after one day. The Female could
not deposit eggs in absence of host.