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The melon aphid, Aphis gossypii (Glover), is one of the major pests of cucurbits and an efficient vector of plant viruses such as Cucumber Mosaic Virus. Host-plant resistance is one of the management strategies that can be used to control this pest. In this study, choice test was conducted to identify antixenotic resistance against melon aphid in eight Cucumis genotypes, namely Hormozgan, Bushehr, Guilan, Girtap, Negeen, Sepehr, Pouya and Armenian cucumber. Choice tests were conducted at 25 ± 1 ºC, 60 ± 5% RH and a photoperiod of 16:8 (L: D) h. After introduction of apterous adult aphids to test arena, the number of aphids on each entry was counted at 2, 4, 6 and 24 hours of release. Total phenolic content, NPK essential elements, leaf thickness and leaf trichome density were also measured to discover any association between these factors and aphid host choice. The most antixenosis effect was observed on 'Bushehr'. Increase in antixenosis correlated with increase in leaf trichomes. Antixenosis can be important mode of resistance by reducing host selection and delaying aphid colonization. The identification of antixenotic resistance in several genotypes provides additional options for management of this pest. Moreover, the factors associated with this mode of resistance can be considered in plant breeding programs.

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Witches' broom disease of lime (WBDL) is a lime disease that has destroyed several citrus orchards in Oman, United Arab Emirates and Iran. WBDL is caused by a bacterium ''Candidatus Phytoplasma aurantifolia'' which is spread through the citrus orchards by a leafhopper, Hishimonus phycitis (Distant) (Hemiptera: Cicadellidae). Leafhoppers are associated with symbiotic microorganisms which provide them with essential amino acids lacking in their diets. Yeast-like relationships with insects are known as common and obligate symbiotic relationship. A prerequisite for the development of future strategies for the symbiotic control of insect pests and insect-vector competence is the identification of insect-associated yeast-like symbionts. In the present study, yeast-like symbionts housed in H. phycitis were investigated in insects collected from 13 districts of citrus orchards distributed in southern Iran (Hormozgan, Kerman, Sistan-Balushestan and Fars provinces). Insects were collected from infected lime trees by a D-Vac and stored at -20 ºC up to the DNA extraction. Total DNA was extracted and PCR was conducted with specific primer sets targeting 18S rRNA and 26S rRNA genes of the symbionts. Results revealed that the vector harboured two yeast symbionts, namely Yeast like symbiont of H. phycitis (Hp-YLS)and Candida pimensis,with a similarity of (98-99%) to those reported from the other Cicadellids. These results substantiate the association of these two endosymbiotic microbiota with H. phycitis which may suggest their ecological interactions. To establish any endosymbiotic relationship and probable interfering in pathogen transmission, further studies are needed.

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The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae) is one of the most destructive insect pests, feeding exclusively on wild and cultivated cruciferous species. The attacked plants produce considerable amount of glucosinolates in response to insects’ feeding. Herein, we studied digestive activities of P. xylostella on four different genotypes of family Brassicaceae including two canola cultivars (SLM₀₄₆ and RGS₀₀₃) and two cabbage cultivars (Green-Cornet and Glob-Master). The highest proteolytic and amylolytic activities of P. xylostella were observed on Green-Cornet and the lowest occurred on RGS₀₀₃ and Glob-Master, respectively. The highest activity of α-glucosidase and β-glucosidases were observed on Green-Cornet and SLM₀₄₆ and the lowest was observed on Glob-Master and RGS₀₀₃. The zymogram analysis revealed different isozymes of protease, trypsin-like and α-amylase in the midgut extract of P. xylostella. Activity of the above mentioned isozymes was inhibited in larvae feeding on RGS₀₀₃ and Glob Master as resistant host cultivars. Also, larvae feeding on the resistant genotypes showed more glucosidase activities, indicating possibility of high glycosinolate existence in the resistant genotypes. By these results we can state that host plant property can affect insect digestive physiology through inhibiting digestive enzyme activities. These findings provide insights into the direct effects of host plants on insect physiology which are conducive to change in insect fitness.

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The fall webworm, Hyphantria cunea (Drury, 1773) (Lepidoptera, Erebidae), is one of the most important pests of forest trees in northern Iran. In order to identify the native parasitoids of this pest a survey was conducted in Guilan province, in 2019. The larvae and pupae of the fall webworm suspected being parasitized, were collected from different host trees and wood piles, and reared under laboratory conditions until the parasitoids emerged. This pest was found parasitized with five species of Hymenoptera, Brachymeria lasus (Walker, 1841) (Chalcididae), Chouioia cunea Yang, 1989 (Eulophidae), Psychophagus omnivorus (Walker, 1835) (Pteromalidae), Pimpla rufipes Brulle, 1846, Virgichneumon dumeticola (Gravenhorst, 1829) (Ichneumonidae), and four species of Diptera, Compsilura concinnata (Meigen, 1824), Exorista larvarum (Linnaeus, 1758), Pales sp. (Tachinidae), and Megaselia scalaris (Loew, 1866) (Phoridae). Among them six species (e.g., P. rufipes, V. dumeticola, B. lasus, E. larvarum, C. concinnata and Pales sp.) are newly reported as the parasitoids of H. cunea from Iran.

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The family Macromesidae Graham, 1959, and the genus Epicopterus Westwood, 1833, from the family Eunotidae Ashmead, 1904, are recorded for the first time from Iran, by two species Macromesus amphiretus Walker, 1848, and Epicopterus choreiformis Westwood, 1833, respectively. Specimens were collected using Malaise traps during 2010–2011 from the Guilan and Qazvin provinces in north-central Iran. Detailed morphological characters of the newly recorded species are provided. The number of Macromesidae and Eunotidae species in Iran is newly raised to one and four species, respectively. An updated list of all known species of these taxa from the Middle East is also included.

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The two-spotted spider mite (TSSM) Tetranychus urticae Koch is one of the most destructive mites in many plants due to its characteristics, such as high reproductive potential, short life cycle, and feeding method. Excessive use of chemical compounds without considering environmental factors has led to high residual toxins in food products and resistance to pesticides. Temperature is an essential non-living factor that affects various biological aspects of pests and pesticide toxicity levels. In this study, the interaction of different temperatures (15, 20, 25, and 30 °C) in the photoperiod (16L:8D h) was investigated on the toxicity of spiromesifen on the adult TSSM. Then the levels of α-esterase and glutathione S-transferase activity were measured. The highest LC₅₀ was recorded at 15 °C after 24 h (LC₅₀ = 21.269 mg ai/l), and the lowest value corresponds to 30 °C after 48 h (LC₅₀ = 0.860 mg ai/l). The level of toxicity also increased with a temperature increase, so the toxicity was recorded 3.6 folds higher at 30 °C compared to 15 °C. The α-esterase and glutathione S-transferase activity also increased with an increase in the temperature, but this increase was significant only for esterase activity. The relationship between temperature and the power of pesticide toxicity in areas with different daily and controllable temperature changes can effectively provide a valuable proposal to reduce pesticide consumption and increase the efficiency of pest control.


 

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 The European grapevine moth, Lobesia botrana (Denis and Schiffermueller) (Lepidoptera: Tortricidae), is a significant pest causing economic damage to vineyards worldwide. In this research, the cold tolerance of the pupae and its relationship with diapause was investigated at 23 ± 0.5 °C, 70 ± 5% RH, and LD 12:12 h. One-day-old eggs were transferred to LD 12:12 h to induce diapause at the pupal stage. Diapausing pupae exhibited a mean supercooling point (SCP) of -24.35 °C, whereas in the non-diapausing pupae (23 ± 0.5 °C, 70 ± 5% RH, LD 16:8 h), it was -23.06 °C, with no significant difference between the two groups. Furthermore, diapausing pupae demonstrated significantly higher cold tolerance (LT₅₀ of -14.43 °C) than non-diapausing pupae (LT₅₀ of -3.33 °C). Diapausing pupae tolerated subzero temperatures without significant changes in the SCP, tolerating 11 °C lower than control pupae due to the short daylength alone. Our results suggest that the diapause state and cold hardiness of L. botrana are independent of changes after SCP, and the insect employs a freeze-intolerant strategy to overcome subzero temperatures. Cold acclimation at -5 and -10 °C for 72 h induced a significant decrease in the SCP of diapausing pupae, while a 72-h cold acclimation had no notable impact on the SCP of non-diapausing pupae. These findings provide valuable insights into the survival mechanisms of the European grapevine moth under cold conditions and diapause-related adaptations.


 

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The experiment was conducted to determine α-amylase activity and the effect of seven plant species extracts including Punica granatum L. (Punicaceae), Rheum officinale B. (Polygonaceae), Rhus coriaria L. (Anacardiaceae), Artemisia sieberi B. ( Compositae), Peganum harmala L. (Nitrariaceae) , Datura stramonium L. (Solanaceae) and Thymus vulgaris L. (Lamiaceae) on α-amylase activity of four stored insect pests including Callosobruchus maculatus F. (Coleoptera: Bruchidae), Rhyzopertha dominica F. (Coleoptera: Bostrichidae), Sitophilus granarius L. (Coleoptera: Curculionidae), and Trogoderma granarium E. (Coleoptera : Dermestidae). Also, gut pH and optimum temperature for α-amylase activity of these insects were determined. It was found that α -amylases midgut pH of all four insect species was acidic and optimum temperature was between 30 and 40 °C. Beyond these temperatures, the α-amylases activities sharply decreased. Plant extracts caused inhibitory activity on insect α-amylases varying from nearly 4% to 95% inhibition. D. stramonium and R. officinali extracts had the highest amylase inhibitory activity among the tested extracts, while methanolic extracts of P. harmala, and T. vulgaris (except for S. granaries α-amylase) showed the lowest inhibitory activity. Gel assays revealed that more than one isoform of α -amylase detected in midgut crude extracts of the four insect pests examined could be inhibited by the plant extracts.

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The tomato leafminer, Tuta absoluta, is a pest that greatly harms crops. Regrettably, the application of insecticides has resulted in the emergence of resistance in the tomato leafminer. Metabolic resistance is the most prevalent form of resistance, characterized by heightened esterase activity, cytochrome P450 monooxygenase, and glutathione S-transferase enzymes encoded by specific genes. This study investigated the metabolic resistance mechanisms associated with fenvalerate resistance in the tomato leafminer and explored the genes' status. Tomato leafminer populations in Iran showed varying levels of resistance to fenvalerate; the Tehran and Urmia populations were the most resistant and sensitive, respectively. The activity level of detoxifying enzymes, particularly cytochrome P450 monooxygenase, was found to be increased in the resistant populations (i.e., Tehran) compared to the susceptible one (i.e., Urmia). Gene expression analyses showed higher transcript levels of P450, esterases, and GSTs expression levels in the resistant population compared to the susceptible population. Our findings indicated that detoxification enzymes, especially cytochrome P450 monooxygenase, and differential expression of related genes contribute to fenvalerate resistance. Identifying the specific mechanisms behind resistance could assist in pest control and resistance management programs.



 

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In this paper, Free Vibration analysis of truncated conical shell Reinforced with single-walled carbon nanotubes for uniformly distribution (UD), resting on Pasternak elastic foundation, based on the first order shear deformation plate theory is investigated. The rule of mixture is used to effect of the properties of nanotubes in the mentioned structure. Based on the displacement field according to the first order shear deformation theory, after determining the strain components in the curvilinear coordinates and simplifying derived relation, we compute the strain components in conical coordinate. Then, the stress components are derived by the Hook’s law. In the next stage, by computing the total potential energy of system by regarding the effect of Pasternak elastic foundation and regarding the suitable functions for displacements, by applying the Ritz method the natural frequency of system have been derived. At the end, the effect of volume fraction of nanotubes, ratio of thickness to radius of cone, elastic constants and other parameters, on the natural frequency of structure have been investigated. Also, it can be observe close agreements between present results and other papers.

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In this paper, free vibration of two-dimensional functionally graded (2D-FG) annular sectorial plate surrounded by Winkler-Pasternak elastic foundation has been investigated. It is assumed that the plate properties vary continuously through its both circumference and thickness according to power law distribution of the volume fraction. Primarily, we calculate the forces and resultant moments and then the total potential energy of system. Then, by applying the Hamilton’s principal any by regarding the first order shear deformation plate theory (FSDT) the governing differential equations have been derived. The numerical differential quadrature method, (DQM), has been employed for solving the motion equations. Two different boundary conditions such as simply supported and clamp-simply supported are considered. Initially, the obtained results were verified against those given in the literature and by ANSYS software and we confident from the obtain results. The effects of geometrical and elastic foundation parameters along with FG power indices effects on the natural frequencies have been studied. The study of results shows that, elastic foundation and FG parameters have significant effects on natural frequencies. By doing this research for 2D-FG materials the characteristic vibration of structure can be controlled by more parameters than 1D-FG materials.

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In recent years, Mg alloys have received much attention as a promising candidate for raw material in biodegradable vascular stent. Forming of Mg alloys is difficult because of poor workability of them at room temperature. Hence this presents a technological barrier to the fabrication of initial micro-tube for a biodegradable stent. With regard to high biodegradability of the magnesium alloy WE43 to manufacture biodegradable stent, it has been selected as initial with casted structure. In this study, for enhancing mechanical properties and attaining micro tube a combination of equal channel angular pressing (ECAP) with extrusion and micro extrusion was used and Mg bars were fabricated to high-quality micro-tubes with refined microstructure. Fine-grained size billets of the WE43 alloy were obtained by one-pass of ECAP. The processed Mg bar was extruded into a bar with 5 mm in diameter. Finally, a UFG and high strength micro tubes with an outside diameter of 3.4mm and a wall thickness of 0.25mm were successfully produced by micro extrusion process. Mentioned processes were simulated using finite element (FE) simulations. The result shows the grain size of Mg incredibly reduced after this combined method and mechanical properties were significantly improved.

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The effect of eight Cucumis L. (Cucurbitaceae) genotypes, including native cucumber genotypes (Hormozgan, Bushehr and Gilan), greenhouse cucumber genotypes (Girtap, Negeen, Sepehr and Pouya) and Armenian cucumber (Cucumis melo var. flexuosus) was studied on the life table and population growth parameters of Aphis gossypii Glover to evaluate antibiosis resistance. The experiment was conducted at 25±1°C, 60±10% RH and a photoperiod of 16:8 hour (L:D). The data were analyzed by Two-Sex MSChart program. The most pre-adult mortality (22.6 %) and the shortest total life span (14.5 days) were recorded for ‘Bushehr’. The net Reproductive rate (R₀) ranged from 43.70 for ‘Bushehr’ to 92.39 nymphs per individual in the case of ‘Pouya’. The lowest value of the intrinsic rate of increase (r) and the finite rate of increase (λ) was observed in ‘Gilan’ (0.378 and 1.460 day⁻¹, respectively) and the highest in ‘Pouya’ (0.471 and 1.602 day⁻¹, respectively). The maximum and minimum mean generation Times (T) were 10.20 and 9.23 days in ‘Gilan’ and ‘Negeen’, respectively. On the basis of these parameters, ‘Gilan’ had the highest antibiosis resistance to A. gossypii. Information on life table of pests and subsequent host resistance evaluation improves IPM programs and leads us to genotype selection for crop breeding programs.

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Collagen is the most abundant protein of animal origin and the most important compound in the connective tissue which is widely used in the food and beverage industry. In addition, recent research has demonstrated the functional, beneficial, and potential properties of collagen extracted from aquatic wastes as nutraceuticals and for delivery systems of sensitive bioactive compounds. Therefore, the aim of this research was considered to study the structural charachters, antioxidant and functional properties of collagen and collagen hydrolysate extracted from the skin of common grouper (Epinephelus coicoides). In the present experimental study, the collagen sample was extracted by acid and enzymatic method and structural characters were studied by Fourier-transform infrared (FTIR) spectroscopy, Scanning Electron Microscope (SEM) and polyacrylamide gel electrophoresis (SDS-PAGE). DPPH radical scavenging, reducing Power and foam producing capacity also assessed.The results of Scanning Electron Microscope confirmed schistose structure, filamentus network, secondary and third structure, and the good interconnection and uniform porus matrix was noticed. The typical characters for type I collagen, including five peaks (amide A, amide B, amide I, amide II and amide III  are observed in the spectrogram of collagen and collagen hydrolysate, also the preserved triple-helical  structure were comfirmed.

The results of the functional properties and antioxidant activity of collagen from orange-spotted grouper skin also showed that with increasing the concentration, reducing power and DPPH radical scavenging ability increased. Comparing collagen and hydrolyzed sample, the foam producing capacity was proved just for collagen.  Finally, it can be said that collagen and hydrolyzed collagen extracted from the skin of orange-spotted grouper with suitable antioxidant properties, and appropriate functional properties can be mass-produced as a bioactive compound and as emulsifier may be used in the food industry and in the production of Functional foods.

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Witches' broom disease of lime caused by 'Candidatus Phytoplasma aurantifolia' is considered as one of the most destructive disease of Mexican lime in southern Iran, Oman, and the United Arab Emirates. The causative phytoplasma is vectored by a leafhopper, Hishimonus phycitis (Distant, 1908). Six ISSR markers and mitochondorial Cytochrome c Oxidase I (COI) gene were used to unveil genetic variation of the leafhopper populations from thirteen different regions of Iran. Analysis of ISSR markers revealed that Forg (Fars) and Qale'e Qazi (Hormozgan) significantly diverged from the other populations. However, the COI sequences were highly conserved among all populations and resided all the populations in a single clade. Mantel test exhibited no correlation between genetic and geographical distances. Our results demonstrated genetic differentiations among the H. phycitis populations, which might have been induced by ecological or geographical isolation and may affect the vectoring capability of this insect.
 

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The pistachio green stink bug, Brachynema germari Kolenati (Hemiptera: Pentatomidae), is one of the most important pests of pistachio nuts in many pistachio-growing regions in Iran(Mehrnejad 2001; Bigham & Hosseininaveh 2010). This insect harbors a gammaproteobacterial symbiont, related to the genus Pantoea, in the numerous crypts of its posterior midgut, which is vertically transmitted by infection of the egg masses and orally acquired by newborn nymphs. In the present study, the effects of the symbiont on host morphology, emergence rates, and mating frequency of B. germari were explored. For this purpose, two symbiont elimination strategies, high temperature and egg surface sterilization, were used and their effects were compared. We found external morphological changes (e.g. abnormalities in notum and wings) as well as significantly fewer emergence rates (in all stages, except for the first instar) in the surface-sterilized and heat-treated insects compared with the controls. Also, the second, third, and fourth regions of the midgut exhibited remarkable morphological changes in the aposymbiotic insects compared with the controls. Besides, less mating frequency was observed in the aposymbiotic population compared with the control. Together, these results provided a close relationship between the bacterial symbiont and B. germari and suggested the importance of the symbiont for the morphogenesis, development, and reproduction of the insect host.

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The ­antifeedant activity of nanoemulsion formulation of arugula Eruca sativa Mill. oil was studied against elm leaf beetle Xanthogaleruca luteola (Müller)(Col.:Chrysomelidae) under laboratory conditions at 25±1ºC, 75±5% RH, and LD 16:8 hours. Ingestive LC₅₀ values of the oil were studied in third instar larvae. Then, physiological parameters were evaluated following 24, 48, and 72 hours post feeding at LC₅₀ level. LC₅₀ values 24, 48 and 72 hours after application were 4.940, 3.791, and 2.938 mg mL^-1, respectively. Arugula oil at LC₅₀ level decreased the nutritional indices including efficiency of conversion of ingested food, relative growth rate, efficiency of conversion of digested food, and relative consumption rate, but increased feeding deterrence index significantly 72 hours post feeding. Nutritional reserves such as total carbohydrate, protein, and lipid contents and also digestive enzymes containing lipase, α-amylase, and protease activity were decreased showing post-ingestive toxicity. The activity of the detoxifying enzyme glutathione S-transferase was increased, indicating that this enzyme may be involved in detoxification of arugula oil, but general esterase did not change significantly. In general, it can be concluded that arugula oil possess antifeedant activity against X. luteola under laboratory condition. It seems that arugula oil has a great potential to be used as effective botanical pesticides. However, further studies such as greenhouse and field experiments are necessary before recommendation and commercialization process.

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The tomato leafminer, Tuta absoluta is a devastating invasive pest that poses a serious threat to tomato crops worldwide. Its extensive global dispersion serves its capacity to adapt to variations in climate conditions. In this context, the pupa is the most resistant stage to prolonged exposure to cold temperatures. Therefore, indicators of cold resistance were studied in overwintering pupae collected from the field and pupae reared under two constant conditions, high temperature, and long day (25°C, 16:8 L:D and 65±5% RH), and low temperature and short day (15°C, 13:11 L:D and 65±5% RH). The results show that the super cooling point (SCP) significantly decreased in December (-20.5±1.2°C) and January (-20.26±0.78°C) with a decrease in temperature. In the laboratory, the decrease in temperature and photoperiod increased the tolerance of pupae to subzero temperatures. Lethal Temperature 50 (LT₅₀) and LT₉₀ of pupae collected in the field were recorded at -13.70 to -10.23°C and -18.73 to -15.37°C, respectively. A comparison of lethal temperatures with the lowest ambient temperature in December and January indicated that T. absoluta has a high overwintering potential in Karaj, Alborz Province, Iran, and can easily survive cold winters.