الفهرس 
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Abstract
Predacious insects of the order Neuroptera are of great importance as naturally occurring biological control agents (NOBCA). Members of the family chrysopidae are called green lacewings. In Egypt chrysoperla carnea, was recorded as a predator on aphids, newly hatched larvae of the cotton leaf worm, mealy bugs, and scale insects. Unfortunately, several parasitoids attacking the green lacewing immature stages and affecting the efficacy.
The study aimed to identify the most important parasitoids that affecting the efficacy of green lacewing immature stages, the natural oscillations of the predator and its preferred directions, which is important for the success of Integrated Pest Management (IPM) programs. The field study was conducted in the Experimental Farm, Faculty of Agriculture, Assiut University, Assiut, Egypt 31° 11’ 21.4188’’ E Longitude; “27° 10’ 48.4824’’ N” Latitude during two successive growing seasons (2021 and 2022). A total of 200 trees (22 years old) of mixed cultivars in a pomegranate orchard were chosen for the present study. The pomegranate orchard was surrounded by clusters of several plantations, such as grape, mango and date palm trees. The farm was divided into five directions (North, South, East, West, and Center), samples were taken per weekly for 10 months during the two study seasons (2021 and 2022).
Extensive and intensive observations were made to collect the incomplete phases of the aphid lion from different crops including beans, alfalfa, wheat, and cotton, but the pomegranate orchard was suitable and adequate to collect the incomplete phases of the aphid lion in abundance and to achieve the objectives of the study. Results can be summarized as follow:
1. Field studies
1.1. Abundance and spatial distribution pattern of adult green lacewing and inhabiting pomegranate orchards
1.1.1. Population fluctuations of adult green lacewing and aphids
The average numbers of green lacewing adults and aphids caught by yellow sticky traps on pomegranate per week and ambient weather factors during 2021 and 2022 growing seasons.
Results indicated that aphids appear early at the beginning of the pomegranate season. This may be attributed to the feeding habits of aphids on the sap of new pomegranate tree buds. It was also noted that the green lacewing appeared later, due to its presence on other plant hosts such as alfalfa at that time.
The average number of green lacewings in both years was (0.58 and 0.95/ trap) less than that of aphids (10.35 ± and 34.55/ trap). This finding may refer to the feeding habits of the green lacewings. Which feed on of aphids, newly hatched larvae of cotton leaf worm, mealy bugs, and scale insects.
The population density of green lacewings and aphids recorded three peaks in both growing seasons. Statistical analysis of the data indicates that the differences in aphids’ population density between the two growing seasons were highly significant and led to the differences in green lacewing peaks. Thus, differences in the population density of lacewings had a relationship with aphids, that C. carnea may locate aphids by smelling their pheromone.
So, the above-mentioned results are of great importance for employing green lacewing populations as biological control agents to reduce aphid populations below the economic injury levels (EIL) in integrated pest management (IPM) approach.
1.1.2. Spatial distribution of adult green lacewing and aphids collected by yellow sticky trap inhabiting pomegranate orchards
The maximum average number of adult green lacewing/trap was in the center of the pomegranate orchard in both seasons. The maximum percentages of adult green lacewings were in the center during both seasons and recorded at 31% and 28% during 2021 and 2022, respectively. The most preferable direction for adult green lacewings was the east northern side during both growing seasons. This finding can be attributed to the predator’s behavior in choosing the center area to aggregate and spread to the other directions for egg deposition.
Concerning the maximum average number of aphids was in the east direction during 2021 and in the north direction during 2022 growing season. The maximum percentages of aphids were 43.36% in the east direction during 2021 and 22.17% in the north direction during 2022 growing season. The most preferable direction for aphids was the east northern side during 2021 season. but was in the northern east side in 2022 season. It is of interest to point out herein that differences in the abundance of aphids in the east and north directions from year to year may be attributed to the optimum conditions preferred for alate aphids to land in suitable directions.
In conclusion, understanding the population dynamics and the dispersion of important natural enemies like C. carnea contributes to the significance of integrated pest management. This research will aid in the development of precise management strategies to strengthen this predator in the field. More research is required to determine the effects of the other parameters on its effectiveness.
1.2. Abundance and spatial distribution pattern of green lacewing parasitized eggs inhabiting pomegranate orchards
1.2.1. Population fluctuations of green lacewing parasitized eggs inhabiting pomegranate orchards
Concerning the relationship between deposited eggs by green lacewing females and parasitized eggs in pomegranate orchards during both growing seasons under field conditions recorded two peaks. Also, attacking deposited eggs by egg parasitoids under field conditions proves excellent synchronization of the host (green lacewing). This phenomenon needs more future studies to avoid a deficiency in the effectiveness of the green lacewing.
1.2.2. Spatial distribution patterns of green lacewing parasitized eggs on pomegranate orchards during 2021 and 2022 growing seasons
The maximum percentage of parasitized eggs was in the east direction of the pomegranate orchard during 2021 growing season. But it was in the north direction of pomegranate orchards (season in 2022). Also, the most preferable direction for the parasitized eggs was the northern east side, making an angle (27º11´04”) during 2021 growing season. However, the most preferable direction for the parasitized eggs was the northern west side and making angle (27º11´03”) during 2022 growing season. Also, these results may be due to the same abiotic factors or other unknown factors.
1.3. Determination the parasitism percentage for collected green lacewing eggs
Results indicated that, in both seasons, the maximum parasitism percentages were (30.36 and 40.36%) in the north direction during 2021 and 2022 growing seasons, respectively. In conclusion, the preferable direction of the parasitized green lacewing eggs was the same direction as the maximum parasitism percentages.
In general, the maximum parasitism percentage in 2021 growing season was 27.26% for the total number of green lacewing eggs (1860). However, during 2022 growing season, it was less than 2021 season with a percentage of parasitism of 23.76% and a total number of green lacewing eggs of (1490). It is of interest to point out herein that the percentage of parasitism increased with increasing egg numbers. So, this finding needs more attention when releasing the predator for controlling insect pests in the field.
2. Laboratory studies
2.1. Species composition of parasitoids attacking immature stage green lacewing inhabiting pomegranate orchards
Extensive and intensive observation of the green lacewing immature stages inhabiting pomegranate orchard revealed the parcens of several parasitoids belonging order Hymenoptera. Under laboratory conditions collected parasitoids were examined and prepared for identification. Two egg parasitoids and three pupal parasitoids were identified. The more dominant egg parasitoids were submitted for morphogenetical study.
2.2. Morphological and molecular identification of dominant egg parasitoids
2.2.1. Morphological identification
The morphological structures of the male and female dominant egg parasitoids were demonstrated in the present work using scanning electron microscopy (SEM) and light microscopy (LM). The morphological characteristics include body length, color, compound eyes, antennae, mouthparts, wings, legs, female abdomen, and external male genitalia.
2.2.1.1. General body coloration
In both sexes, the general body coloration is black from the head to the first segment of the abdomen. Except the antennae are brownish yellow, and the legs are dark brown at the beginning and light brown at the tip.
2.2.1.2. The head
• Compound eyes:
Compound eyes cover a significant amount of head space. Detail of a compound eye showing interstitial hairs distributed across the eye at an angle between three sides. There are three ocelli in front of the forehead.
• Antennae:
In both sexes, the antenna of the egg parasitoid is a geniculate type. The antenna in males has 12 segments, while in females, it has 11 segments, and the apical segments are club shaped. The male flagellomeres are elongate and cylindrical with the apical segment tapering evenly to an acute tip. The first four flagellomeres of the female antennae are elongated, cylindrical, and closely joined. The apical five segments are quadrate and cylindrical.
• Mouthparts:
The mouthpart’s structure is typical of the chewing type. Mouthparts consist of well-developed mandibles, maxillae, and labium.
2.2.1.3. The thorax
Thorax raised high above the level of the abdomen. In the dorsal view of the thorax, there are long and tiny hairs spread. Metascutellum (=dorsellum) there are interstices smooth in deep, regular reticulation.
• Wings:
The forewing is relatively broad, covered with tiny hairs, with longer hairs forming a fringe on the perimeter of the wing. Hindwings bear a fringe of long setae along the posterior margin. The length of post marginal vein is forewing twice as long as the stigma vein.
• Legs:
The legs of egg parasitoids are slender and ambulatorial. Each leg has a coxa, two segmented trochanters, femur, tibia, five segmented tarsi, and a two-claw apical tarsomere. Tibiae has well-developed, branching spurs on the apex.
2.2.1.4. The abdomen
The abdomen is small in comparison with the size of the thorax, narrower and only a little longer than the latter.
• External male genitalia
Male genitalia of egg parasitoid consist of three digital teeth (on each side) and tiny. Laminae volsellares: an extended plate with signs of more severely sclerotized rods on the sides. Very small and rounded at the apex is the aedeagal lobe.
2.2.2. Morphometrics for egg parasitoid
• Body length (BL)
Body length of an adult egg parasitoid female ranged from 630.32 to 680.75 μm with an average of 653.21 ± 18.16μm. However, male measurements had an average of 723.05 ± 28.65μm and ranged from 698.20 to 771.99μm. The above-mentioned measurement data indicated that the female body length is shorter than the male, each collection (n=5) for body length measurements.
• Antennal length (AntL)
Measurements of data on male and female antennae indicated that the male antenna was longer than that of the female. The flagellar width (FW) of females is larger than males. Antennal club length (ACL) of the male was longer than that of the female.
• Wing length (WL)
Measurements of the male and female forewings indicated that the male wing length is longer than female. Also, male wing width is longer than female.
• Abdominal measurements Female (ALF)
The female measurements of abdomen length max= 323.41μm, min= 257.22 μm with an average of (290.50± 18.14μm). The abdomen width max= 213.41μm, min= 177.50 μm with an average of (199.63± 11.10μm). However, abdomen area max= 53303.34 μm2, min= 33769.23 μm2 with an average of (43231.61± 5271.81 μm2). Each collection (n=10) for female abdominal measurements.
• External male genitalia (ML)
The measurements of male genitalia include general length (GL), general width (GW), Aedeagal Lobe (AL), basal Ring (BR), and Aedeago-volsellar shaft (AVS). The general length max= 156.44 μm, min= 136.51 μm with an average of (146.70± 5.43μm). Also, general width max= 46.25μm, min= 37.61μm with an average of (41.67± 3.09μm). The aedeagal lobe max= 40.99μm, min= 20.68μm with an average of (31.18± 7.67μm). Basal Ring (BR) max= 60.17μm, min= 35.73μm with an average of (49.08± 8.03μm). Aedeago-volsellar shaft (AVS) max= 116.2μm, min= 85.74μm with an average of (99.65± 10.57μm). By discussing the above-mentioned results indicated that measurements of male genitalia are considered one of the most important characteristics for the classification of the species of family Scelionidae.
2.2.3. Molecular genetic identification
The current study used DNA sequences of the COI gene to describe and identify the prevalent species inhabiting pomegranate orchards at the Experimental Farm, Faculty of Agriculture, Assiut University, Assiut as Telenomus remus. We believe our finding based on COI was correct given that they aligned with multiple GenBank sequences deposited by multiple authors in multiple studies and were designated as Telenomus remus. The results of COI confirm that our tested species can be identified as Telenomus remus. According to morphological and molecular methods, confirmed that the egg parasitoid recorded during the study is T. remus.