Showing 14 results for Majeed
Volume 1, Issue 1 (3-2012)
Abstract
This study was conducted to evaluate the age-specific functional response of Psyllaephagus zdeneki Noyes & Fallahzadeh (Hymenoptera: Encyrtidae) at different nymph densities of olive psyllid, Euphyllura pakistanica Loginova (Hemiptera: Psyllidae). Due to parasitoid behaviour of feeding and parasitizing the host, both traits were separately explored on a daily functional response. Results of logistic regression revealed a type II functional response of the wasp independent of their ages. The handling time (Th) and searching efficiency (a) were estimated using the Rogers equation. The highest searching efficiency for both parasitism and feeding was observed in the first five days of the adult age. The handling time for parasitism and host feeding increased with the age of female wasp. The highest searching efficiency and shortest handling time for host attacked (Parasitism and feeding) were gained in day 5 and day 2 and maximum parasitism and host feeding in days 2 and 3 of adult female age, respectively. We conclude that P. zdeneki demonstrated a reasonable performance as a potential biocontrol agent by feeding and parasitism of E. pakistanica which gained its maximum efficiency within 2 to 5 days of its life.
Volume 6, Issue 2 (6-2017)
Abstract
Bactrocera zonata (Saunders) (Diptera: Tephritidae), an extremely aggressive species infesting some of the main commercial fruit and vegetables, has been subjected to a diverse array of control approaches. In the current study, performance of various Methyl Eugenol (ME) dispensers in combination with an organophosphate insecticide, Malathion, were evaluated against B. zonata in two consecutive years (2006-2007). Treatments efficacy was studied in various months using the criterion of trapped B. zonata flies. ANOVA revealed a significant difference among various application methods in both fruit infestation rate and capture of B. zonata flies. So that impregnation of chipboard block in ME caused the lowest B. zonata infestation and the highest B. zonata capturing values in both years. Population fluctuation study revealed a major peak for B. zonata in September i.e., mango ripening time. According to our results, it could be suggested that chipboard dispenser is the best application method as attractant in bait trap which exhibits more potent and longer lasting activity.
Volume 6, Issue 4 (12-2017)
Abstract
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.
Volume 7, Issue 1 (3-2018)
Abstract
The effect of thyme Thymus vulgaris L. androsemary Rosmarinus officinalis (L.) essential oils on life table parameters of red rose aphid Macrosiphum rosae (L.) oncut flower rose Rosa hybrida L. were investigated in laboratory conditions (27 ± 2 oC, 70 ± 5% humidity and a photoperiod of 16L:8Dh), during 2014-2015. The results on the basis of LC50 values showed that the M. rosae was significantly more sensitive to the oil of T. vulgaris (LC50 = 36621 ppm) than R. officinalis (LC50 = 57565 ppm). Also, Investigation of the thyme essential oil on life table parameters of M. rosae showed that the net reproductive rate (R0) values changed from 16.62 ± 2.31 to 29.10 ± 1.97 female offspring, the intrinsic rate of increase (r) values ranged from 0.177 ± 0.01 to 0.229 ± 0.13 day-1, the mean generation time (T) was 13.92 ± 0.22 to 15.88 ± 0.19 days, the DT values ranged from 3.01 ± 0.05 to 3.90 ± 0.007 days and the finite rate of increase (λ) values was 1.19 ± 0.003 to 1.26 ± 0.06 day-1. Also, the rosemary essential oil on life table parameters of red rose aphid revealed that the R0 values ranged from 17.87 ± 1.97 to 31.97 ± 1.98 female offspring,the r values ranged from 0.185 ± 0.02 to 0.237 ± 0.001 day-1, the mean generation time (T) was 14.45 ± 0.23 to 15.99 ± 0.21 days, the DT ranged from 2.85 ± 0.14 to 3.71 ± 0.14 days and the λ values was 1.20 ± 0.01 to 1.27 ± 0.02 day-1.The results revealed that the essential oils of rosemary and thyme used in this research had a significant difference on population parameters of rose aphid. The maximum mortality percent of M. rosae population registered 86.12 ± 1.02% and 90.21 ± 1.12% for rosemary and thyme essential oils, respectively. Hence, T. vulgaris had higher insecticidal effect than R. officinalis essential oil on rose aphid population.
Volume 7, Issue 1 (3-2018)
Abstract
Piarom is considered as one of the most important semi-dried date fruits in Iran which has been highly affected by stored pests. The current study was aimed to evaluate the effects of the modified atmosphere packaging (MAP) and vacuum packaging (VAP) methods on storage pests control and date quality. To do so, Piarom variety were packaged in two package systems, including passive modified atmosphere and vacuum package system. The control samples were kept unpackaged. The packages were kept under two different storage conditions; at 4 °C and 55 ± 10% RH, and 25-27 °C and 70 ± 5% RH for 30, 60, 90 and 150 days. The experiment was carried out based on a completely randomized design arranged in factorial with four replicates. The results showed that Indian meal moth Plodia interpunctella (Hübner)and sawtoothed grain beetle Oryzaephilus surinamensis (L.) are the most important storage pests with 87.5 and 12.5% contamination, respectively. The passive MAP and VAP reduced the pests infestation rate significantly compared to control. Also, they could better preserve pH (5.88 and 5.85 for MAP and VAP, respectively) than the control (5.78). Changes in water activity in MAP and VAP were almost the same at the two storage conditions i.e., ambient and at 4 °C and was significantly different from the control. The maximum water activity change was observed in control treatment.
Mahjoora Majeed, Mohd Majid Jamali, Shafqat Jabbar Mir,
Volume 7, Issue 1 (3-2021)
Abstract
The Indian species of Entedon Dalman (Hymenoptera: Eulophidae: Entedoninae) are reviewed. The review includes seven species, of which E. shivalikensis Majeed & Jamali sp. nov., E. dehradunensis Majeed & Jamali sp. nov. are described and illustrated. Entedon thoubalensis (Chisti & Shafee, 1983), E. gunturensis (Shafee & Rizvi, 1985), and E. longicorpus (Khan & Shafee, 1982) are redescibed and diagnostic characters are presented for two species: E. punctiscapus Thomson, 1878, E. pempheridis Ferrière, 1930. An identification key to Indian species of the genus Entedon is also provided.
Volume 8, Issue 1 (1-2019)
Abstract
Health and environmental side effects of chemical insecticides and development of resistant population of Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) to pesticides have resulted in increasing demands for non-chemical control approaches against this pest. In this research, the efficacy of two biological control agents were studied under field condition. Treatments consisted of releasing Habrobracon hebetor (Say) (Hymenoptera: Braconidae), Trichogramma evanescence Westwood (Hymenoptera: Trichogrammatidae) and combination of H. hebetor + T. evanescence (HABROBRACON-TRICO). The results revealed significant differences in the number of infested tomato fruits among treatments and harvesting times. The infested fruits was the lowest (2.68 ± 0.14%) in plots treated by HABROBRACON-TRICO. Moreover, the highest (3.36 ± 0.50%) and the lowest (2.88 ± 0.22%) damaged fruits was recorded in the second and fourth harvesting times, respectively. There was significant interaction between harvesting times and treatments. Regarding the tomato yield in treatments, findings revealed significant difference among treatments in both main harvesting times. However, there was no significant differences in total yield in treatments. It could be concluded that biological control agents can be used as a promising alternative for synthetic insecticides in control of H. armigera in tomato farms without significant crop losses.
Volume 9, Issue 2 (2-2020)
Abstract
Despite successful lime witches'-broom (LWB) phytoplasma transmission by Hishimonus phycitis to the lime trees and Bakraee seedlings, there is no published document regarding LWB transmission by H. phycitis to lime seedlings. To study the possibility of vector-based transmission to lime seedlings, the feral leafhoppers were collected in LWB-infected lime orchards and caged on one-year old Mexican lime seedlings. Six months after inoculation, 50% of inoculated seedlings showed typical symptoms of LWB and were strongly positive in PCR assays. To our knowledge, this is the first report of transmission of Ca. P. aurantifolia to Mexican lime seedlings by H. phycitis under greenhouse condition.
Volume 10, Issue 4 (11-2021)
Abstract
Habrobracon hebetor Say (Hymenoptera: Braconidae) is an ectoparasitoid wasp in the family Braconidae and is widely used in biological pest control. Little information is available on the genetic diversity of geographically isolated populations of H. hebetor. In the present study, we assess the genetic structure and diversity of geographically distinct populations of H. hebetor collected from different regions of Iran. To this end, 19 populations of H. hebetor (Dehloran, Hamadan, Minab, Rudan, Ahvaz, Sari, Semnan, Bandar Lengeh, Haji Abbad, Jiroft, Shiraz, Sarpol-e Zahab, Gorgan, Isfahan, Urmia, Kahurestan, Taziyan, Isin, and Sarkhun) were collected from natural niches. For each population, we sequenced a ~660 base pair fragment of Cytochrome Oxidase subunit I (COI) successfully. Analysis of molecular variance revealed sharp differentiation among H. hebetor populations. Populations from Ahvaz, Dehloran, Jiroft and Minab were the most genetically diverged. A Mantel test showed significant positive correlation between genetic and geographic distances (r = 0.47, P < 0.001). The phylogenetic analysis clustered the populations into two major groups (A and B) (100); the major part was assigned to group A. Group B mainly included the populations from southern Iran. Based on these results, we conclude that H. hebetor in Iran is comprised of many diverse populations. These may be successfully applied in innundative release programs.
Volume 10, Issue 4 (11-2021)
Abstract
Tomato leafminer moth Tuta absoluta (Meyrick) is an important pest of the tomato plant. Light traps can play an influential role in reducing the pest population. Different light colors, three trap sizes, and three installation heights were evaluated under laboratory conditions. The light colors were white, yellow, green, red, blue, and blacklight blue (BLB). The traps, transparent containers of three sizes were 8.5, 10.5, and 14.5 cm in diameter and 15, 19, and 26 cm in height, respectively. The trap installation heights were 50, 75, and 100 cm above the plants’ canopy. The BLB color proved significantly more attractive to T. absoluta, followed by yellow and white colors. The light traps captured more males than females and more mated females than virgin ones. Both of the larger traps (10.5 cm d × 19 cm h and 14.5 cm d × 26 cm h), and higher installed ones (100 cm and 75 cm above the plants), captured a significantly higher number of moths compared to the smaller trap size and lower installation height. Accordingly, for mass trapping of moths, light traps with BLB source of light, with 10.5 cm in diameters and 19 cm in height, and installation at 75 cm above the canopy is recommended in greenhouses.
Volume 17, Issue 109 (March 2021)
Abstract
Green mold rot disease caused by Penicillium digitatum is the most economically important postharvest disease of lime fruit in all production areas. In this research, effects of essential oils (Cinnamomun verum, Eugenia caryophyllata, Thymus vulgaris, Zataria multiflora) for controlling green mold in Mexican lime (Citrus aurantifolia cv. Mexican lime) fruit were studied. Mexican limes were inoculated by Penicillium digitatum suspension and were immersed with the essential oils at three levels 0 (as control), 0.1 and 0.2% (v/v). Then, fruits were kept at 8±1oC and 90-95% relative humidity for 21 days. The results showed that the essential oils significantly affected fruit decay, weight loss, L*, a*, b*, total phenolic content and total antioxidant activity. After 21 days of storage, total phenolic content and total antioxidant activity of treated fruit with essential oils were higher compared with the control. In addition, essential oils were effective in decay and water loss control, and decreasing L* and b* compared with the control. The garden thyme essential oil at 0.2% decreased postharvest decay seven times lower than control but increased total phenolic compounds and antioxidant activity compared to the control 21 days after storage. Therefore, garden thyme essential oil has a strong effect on controlling green mold and maintaining quality of Mexican lime fruit.
Volume 19, Issue 123 (May 2022)
Abstract
Abstract
The use of natural ingredients such as edible coatings is considered as an environmental friendly way to control post-harvest fruit rot as well as delay fruit senescence. The aim of this study was to investigate the effects of edible coatings for controlling fruit rot caused by Penicillium digitatum and some qualitative characteristics of Mexican lime during storage. Mexican limes were inoculated with fungi suspension and were immersed in carboxymethyl cellulose (CMC), hydroxylpropyl methylcellulose (HPMC) and sodium alginate (ALG) coatings at four concentrations of 0 (control), 0.5, 1 and 1.5%. Then, Mexican lime fruit were stored at temperature of 8 ° C and relative humidity of 90-95% for 21 days. The results showed that edible coatings showed significant effects on fruit rot, weight loss, percentage of soluble solids, titratable acid, L *, a *, phenolic content and total antioxidant activity. Among the edible coatings, CMC at 1.5% reduced the fruit rot caused by green mold (77%) and reduced the weight loss (80%), TSS (5%) and increased the titratable acidity (33%) and total antioxidant activity (10%) compared to the control after 21 days of storage. Therefore, the use of edible coatings, especially 1.5% CMC, can maintain qualitative characteristics of Mexican lime and reduce the rot. Therefore, it can be used as an environmental friendly method to maintain fruit quality and reduce post-harvest waste.
Volume 22, Issue 4 (winter 1401 2022)
Abstract
Introduction:
According to the models of growth, renewable and non-renewable energy affect economic growth, but the consumption of renewable energy due to less pollution, contributes to sustainable growth. So, countries strive to create the conditions for the use of renewable energy, such as electricity. By balancing competition in market such as the electricity market, on the micro level surplus of consumer and producer welfare is maximized without government intervention, and the incentive for the private sector to enter the market increases. On the macro level, due to lower prices and increased production, electricity consumption as renewable energy increases and reduces environmental degradation and increases sustainable growth. Over the past decades, in the electricity industry, natural monopoly conditions have been established in the sectors of production, transmission and distribution, and the surplus of consumer and producer welfare has not been maximized, so government intervention was justified. In recent years, due to technological advances and the elimination of natural monopolies, the incentive for the private sector to enter the electricity sector has been strengthened. The purpose of this article is to measure the degree of competition in 9 electricity companies in Iran during the period 2011-2019.
Methodology:
In order to measure the degree of competition in Iran's electricity industry, two structural approaches, i.e., Entropy coefficient and non-structural Panzar-Rosse were used.
The entropy measure is used as an alternative to variance, in fact entropy is the inverse measure of concentration, when entropy increases, concentration decreases:
E=i=1nSi.log1Si , 0≤E≤log(n) (1)
Si is the market share and the value of this index is equal to zero for the monopoly market and increases nonlinearly as the market becomes more competitive.
Measurement of degree of competition by Panzar-Ross method, using the GMM method is as fallows:
LnTRit=α0+α1LnQit+βLLnWLit+βKLnWKit+βELnWEit (2)
WLit
is the labor input price, WKit
is the capital input price, WEit
is the energy input price of the power generation company i in the time period t. TRit
is total revenue, Qit
is production of the i-th power generation company at time t. In the dynamic specification, the Panzar-Rosse criterion for evaluating the market structure is defined as follows:
PRH=i=13βi1-α1 (3)
If i=13βi=1 , the market is competitive and a decrease (increase) in the price of inputs causes the same decrease (increase) in marginal cost and marginal revenue. If 0<i=13βi<1 , the market has monopolistic competition and is between competition and monopoly.
Results and Discussion:
The calculation of entropy coefficient, which is one of the structural methods in measuring competitiveness, obtained a number equal to 0.215 for the Iranian electricity industry during 2011-2019. Considering that the mentioned number is between zero and one, it shows that the concentration in Iran's electricity industry has decreased during the period under review and this industry has been placed in a state between competitive and monopoly. In other words, the conditions of the electricity industry have moved out of the traditional state and full monopoly, although it still needs to establish arrangements to become more competitive and close to full competition. On the other hand, Panzar-Rosse non-structural method was also estimated and its index was calculated, which obtained a value of 0.253. This amount of Panzar-Rosse non-structural index also confirms the results of the non-structural approach in Iran's electricity industry. Due to the fact that the results of both structural and non-structural approaches in calculating the level of competitiveness in Iran's electricity industry confirm each other, more confidence is created regarding the obtained result.
Conclusion:
Considering the important and effective role of electricity in other industries of the country, the existence of more competition that leads to a decrease in the price and increase in the production of electricity, from a micro point of view, it has led to an increase in consumer and producer surplus, and from a macro point of view, it has also led to a reduction in environmental pollution. Reducing the exploitation of non-renewable energies and as a result of intergenerational justice and ultimately the realization of sustainable growth and development. Although the results of the calculation of competitiveness indicators indicate that the electricity industry is moving away from the monopoly state and moving towards the competitive state, more efforts should be made in order to increase the degree of competition and achieve complete competition in the country.
In this way, the country's economic managers and policy makers should increase the number of power plants in Iran's electricity network while removing the existing legal obstacles on the path of restructuring from monopoly to full competition in the country's electricity industry in order to reduce the level of concentration and monopoly in Iran's electricity market. On the other hand, creating a suitable environment for the correct and healthy competition of electricity companies, improving the productivity of production inputs and using the optimal combination of inputs through research and development, as well as short-term and long-term planning to improve the level of production and improve the cost structure, and encouraging and supporting elites and inventors in line with the development of new electricity production plans and technologies such as solar electricity technology can help to make the structure of the electricity industry more competitive.
Volume 24, Issue 1 (January 2023)
Abstract
In this article, the effect of using phase change materials to improve heat transfer in power distribution transformers has been investigated experimentally. To enhance the cooling of the transformer, a new method has been proposed, which involves adding paraffin inside aluminium containers that are sealed to the transformer oil. The test setup includes an electric transformer filled with transformer oil, two electrical heaters, a power regulator, a thermal camera, oil insulation measuring device, and temperature sensors placed at various locations. The experimental results demonstrated that the addition of phase change materials to the electronic transformer oil led to a decrease in the temperature of the transformer, particularly in summer weather conditions. Additionally, the mean temperature of the transformer oil was reduced from 46.7 to 42.5 degrees Celsius by adding 8 kg of paraffin. However, it was observed that when the temperature increases suddenly and rapidly within an hour, these materials are ineffective in dissipating the heat and reducing the temperature of the transformers. Additionally, the research examines the impact of continuous and high-temperature increases on the oil electrical insulation. The results revealed that using phase change materials increased the voltage that the oil could withstand as an electrical insulator from 56.8 kV to 61 kV.