جستجوی مقالات مرتبط با کلیدواژه « biological characteristics » در نشریات گروه « کشاورزی »

Three species Rutilus frisii, Alburnus chalcoides and Vimba persa are the most valuable fish that migrate to southern Caspian rivers especially Sefidroud river. In this study, the temporal and spatial distribution of was investigated based on presence and abundance of fingerling fish in 8 stations of the Sefidroud River, from the estuary to the Sangar Dam, during one year from March 2021 to December 2022.</span></span></span> According to the environmental conditions of stations, the sampling was done with an electrofishing instrument and a throwing net with mesh size 6 mm. The results showed that the abundance of fish fingerlings is minimal in the winter and their maximum abundance coincides with the reproduction time and after their adult spawning. The maximum abundance of these fingerlings along with their spatial distribution, also shows their migration pattern towards the Caspian Sea. The abundance of Rutilus frisii in the pebble and gravel beds of the upstream stations was the highest in April and the abundance of the Alburnus chalcoides and Vimba persa in the gravel-mud beds of the middle stations up to the estuary was the highest in August-September. The presence of Rutilus frisii fingerling, with an average weight of 2 g. was high in near to estuary in August while the other two species were present in the middle stations with high abundance until November. Rutilus frisii with weigh more than 3 grams in different stations in autumn and winter indicate the adaptability and residency of a number of fish in the river. The present study can provide some guidelines to the fish stocks restoration centers of Caspian Sea for releasing Kutum fry in the upstream areas, or fish fingerling in the middle of the river at an earlier time. This plan can be tested in a pilot program.

The health of the soil, as an ecosystem, influences the health of other ecosystems. The most essential factors associated to soil quality are its physical, chemical, and biological features, as well as its fertility. However, it is influenced by the type of plant that grows in it. Paying attention to the type of species and their effects on the qualitative characteristics of the soil as a management strategy can help maintain the quantity and long-term stability of restored areas in arid and desert areas in many land restoration projects, particularly in arid lands with limited resources. The purpose of this research is to look into the effect of the Ziziphus tree on physicochemical, microbiological, and stoichiometric ratios of soil in the arid region surrounding the Persian Gulf in the province of Khuzestan. For this purpose, 15 mixed soil samples were randomly selected from the surface soil at the foot of the Ziziphus tree, and 15 mixed samples were selected from the control areas in locations where the Ziziphus tree is not present. The characteristics of the soil samples were the same, including texture, acidity, organic carbon, organic matter, nitrogen, phosphorus, and potassium. The independent t-test was carried out to determine whether there was a significant difference between the two sample groups once the prerequisites for the two sample groups, such as the normality test and the homogeneity of variances, were completed. The results showed that in the Ziziphus samples, organic carbon was 41%, organic matter 47%, nitrogen 69%, C:K ratio 24%, and N:K ratio was 42% higher than in the control area with no Ziziphus. In terms of biological indicators, the Ziziphus samples rose 91% in basic respiration and 90% in microbial biomass carbon, indicating an increase in organic matter mineralization and soil health. In terms of the balance of ions in the exchange phase and solution. The results demonstrate that an increase of one unit in SAR raises the ESR level in the control samples by 1.6 times, compared to the side samples. This indicates that as the concentration of divalent ions in the solution phase increases, the exchange sites where the tree is absent, sodium ions will fill those spaces more quickly. According to the above findings, it can be concluded that using Ziziphus in land restoration projects improves microbiological conditions while also restoring the soil and enhancing its fertility and health.

The most important element in the implementation of cotton IPM is the use of healthy seeds with high vitality. In a few years, cotton seed bugs have significantly increased their population in cotton fields and affect the quantitative and qualitative properties of seeds by feeding on them. Adults and nymphs of Oxycarenus hyalinipennis Costa feed on the contents of cottonseed, resulting in a loss in seed weight, germination rate, oil, protein and nitrogen content. The activity of the genus Oxycarenus on cotton fibers disrupts the ginning process and causes spotting, soiling and reduced quality of cotton fibers. Insect pests are important factors that reduce the yield of cotton crops. Proper control in the field requires adequate knowledge of the species of pest, its biology and the extent of its damage to the cotton plant.Due to the increase in the population of seed bugs in cotton fields in recent years, it was necessary to determine the biological characteristics, the predominant species of these seed bugs and their impact on the quantitative and qualitative characteristics of the seed and was investigated in this study.

For this purpose, a study was conducted in 2016-2017 in which seed bugs were collected from the cotton fields of Hashemabad Cotton Research Station and sent to Insect Classification Research Department of Iranian Plant Protection Research Institute to identify and confirm the genus and species. The insects were cultured under laboratory conditions. Biological factors of the insects such as adult life span, total nymphal life span, pre-oviposition period, oviposition period and total life cycle were evaluated. Morphological characteristics such as length, width and weight of adult male and female insects were also studied. To study the effects of the pest on the physiological characteristics of the seeds during the period of boll opening in the cotton field, 45 bolls were randomly isolated and covered with paper bags, and 45 marked bolls were naturally exposed to the pest. The seeds were sampled in the field in three stages at intervals of ten days. Necessary investigations on quantitative and qualitative characters of the seeds were carried out in the laboratory of the institute.

The seed bugs were identified under the scientific name Oxycarenus hyalinipennis Costa (Hemiptera: Oxycarenidae). Laboratory studies on insect biology revealed that adult longevity, total nymphal duration, pre-oviposition time, oviposition time, and total life cycle Mean (±SE) 32±2.20, 13.6±2.08, 10.69±1.35, 19.16±2.27, and 30±2.47 days, respectively. The results showed that the average weight of cotton seeds was highest in isolated bolls with an average of 10.71 grams. Thus, the average weight was 1.33% and 27.1% higher than plants whose bolls were not isolated and cotton seeds exposed to beetles, respectively. In isolated cotton seeds in the field, 20.5% less soluble carbohydrates and 59.1% less phenols were observed than in seeds exposed to pests.

When the population of cotton seed bugs increases, this pest can significantly damage the cotton crop by reducing the potency and other quantitative and qualitative properties of the seeds.

Biological control of the tomato fruit worm, Helicoverpa armigera (Hübner) by means of inundative release of the egg parasitoid, Trichogramma brassicae (Bezdenko) is a part of an IPM program on tomato crops in Iran. This research was conducted to evaluate the effects of ten commercial tomato cultivars including Aras, Atrak, Korall, Mobil, Rio Grande, Sivand, Super Chief, Super Mobil, Super Queen and Super Urbana on biological characteristics of T. brassicae was studied at 26±1°C, 60±10% RH and a photoperiod of 16:8 L:D hours. The mean longevity of female parasitoid wasps ranged from 7.10±0.56 days on the Super Mobil to 8.05±0.49 days on Rio Grande without significant differences. Developmental period from egg to adult of T. brassicae on Super Urbana was highest (8.61±0.03 days) and lowest on the Aras (8.04 ± 0.02 days). The rate of parasitism was lower on the Super Urbana with 30.08 ±1.40% and highest on the Atrak with 35.86±1.56%. The average number of parasitized eggs by T. brassicae was higher (67.85±4.59 eggs/female) on the Rio Grande and lower on the Super Mobil (59.35±5.72 eggs/female). Female-biased sex ratio varied from 59.54±0.54% on the Aras to 62.65±0.40% on Rio Grande. The number of parasitoid progeny per host egg was highest on Super Chief (1.45 individuals per parasitized egg) and was lowest on Aras (1.37 individuals per parasitized egg).The percent emergence was not influenced by tomato cultivars and was about 90% for the entire treatments. The results suggest that differences between tomato cultivars are the causes of variation in the results of T. brassicae parasitism.

Golden barb, Carasobarbus luteus (Heckel, 1843), belongs to the Barbus genus and is one of the freshwater species of Iran and native to Shadegan wetland. Some biological characteristics of Carasobarbus luteus were studied in Shadegan Wetland. Monthly samples were collected from five stations; Doragh (Mahshahr), Rogabe, Khorosy, Salmane and Atish from April 2013 to Mars 2014. 1608 specimens (276 males and 1332 females) were collected and measured. Results showed Mean±s.d length values for the male and female were calculated as 161±28(110-222), 174±38(95-280) mm respectively and mean±s.d weight values were 60±31(15-175), 80±39(15-370)g respectively. The length-weight relation were calculated as W=0.00003L2.83 (R2=0.84) for males, and W=0.0001L2.80 (R2= 0.86) for female; that determined negative allometeric model. The mean values of condition factor (K) were 1.77± 0.14 in males and 0.78± 0.27 for females and have no significant different (P>0.05). The spawning peak was determined in April, and length at maturity (LM), consume per biomass (Q/B) and production per biomass (P/B) were calculated for males and females as below LM=152, 139 mm; P/B= 0.71, 0.52 and Q/B=15.41, 12.37 respectively.

The present work was conducted to study the biological characteristics of giant snakehead, Channa micropeltes, a popular ornamental species in the world. This species is native to Southeast Asia and also is distributed in Thailand, Laos (Mekong Basin), Vietnam, Malaysia, Sumatra (Bangka and Belitung Islands), Kalimantan and northern Java. Among the environmental characteristics, vegetation plays an important and key role in the habitat suitability of this species. This vicious predator has been introduced to other countries such as China, Philippines, Singapore, Italy and the United States. So far, many reports have been recorded on ecological consequences of introducing this invasive species, including the Philippines and Malaysia. Experts believe that introducing of giant snakehead to breeding cages will reduce the populations of other fish, including Chinese carp and tilapia, and thwart their breeding project. The information presented in this study can be a good guide for researchers and ichthyologists to study the biological and ecological characteristics of giant snakehead (C. micropeltes) in Iran.

The cotton mealybug, Phenacoccus solenopsis Tinsley, is a phytophagous insect with high populations causing serious damage to the Chinese hibiscus shrubs (Hibiscus rosa-sinensis L.) from south of Iran. This research was conducted to determine the host preference of Aenasius bambawalei Hayat when had choice or no-choice access to different stages of cotton mealybug. Moreover, biological characteristics and body size of wasps when reared on third nymphal instar and adult females was studied under laboratory condition. According to the results, female wasps did not parasitize the first nymphal stage. The second nymphal stage was parasitized without any adult wasp emergence. The results revealed that the percentage of mealybug mummified, and sex ratio (% female) was significantly higher when mealybug hosts were parasitized at adult females compared to third nymphal stage, in both choice and no-choice access. The developmental times (days) and body size (hind tibia length and antenna length) of A. bambawalei females and males developing in cotton mealybug adult female was significantly longer than those reared on third nymphal instar. The results indicated the high control ability of A. bambawalei, on the older growth stages of cotton mealybug. It is hoped that this parasitoid wasp can be used as a biological agent to control Ph. solenopsis, on the Chinese hibiscus shrubs, H. rosa-sinensis.

Macrolophus pygmaeus Rambur is an most omnivorous predator which has considered in integrated pest management programs, especially for greenhouse pest management. In this study, biological properties and life table statistics of M. pygmaeus by feeding on Artemia urmiana Gunther cysts and Ephestia kuehniella Zeller eggs were studied under laboratory conditions (25±1°C, 65±5 % relative humidity and 16:8h L: D photoperiod) with 60 replications. The pods of green bean Phaseoulus vulgaris L. served as oviposition substrate and the moisture source. Developmental time of nymphal stages which fed by of E. kuehniella eggs and Artemia cysts were 17.04±0.11, 18.06±0.18 d for males and 17.31±0.09, 18.17±0.15 d for females respectively and were significantly different as well as intrinsic rate of increase (rm) was 0.080±0.005 and 0.064±0.006 d–1 respectively. Also, net reproductive rate (R0) was 18.12±2.97 and 10.70±2.43 eggs/individual on those food regims respectively. Furthermore, mean generation time (T) was estimated as 35.93±0.33 and 36.66±0.53 d respectively. Meanwhile, the reproductive parameters on flour moth larvae have been significantly higher than Artemia cyst. The results showed that feeding on E. kuehniella reduces nymphal period, while increases productivity and longevity of adults. According to the present findings, E. kuehniella is more suitable prey for rearing of this predator, but in absence of access to E. kuehniella, rearing on Artemia cysts is also possible.

Following sugarcane production extension in Khuzestan province, some pests appeared in sugarcane fields and sugarcane stem borers, Sesamia spp. were the most important among them. Development, reproduction and life table parameters of the parasitoid wasp, Telenomus busseolae Gahan on the sugarcane stem borer Sesamia cretica Lederer were studied at five constant temperatures (20, 25, 28, 30 and 35±1°C, 60±5% RH and a photoperiod of 16L:8D h.). The duration of pre-adult stage decreased with increasing temperature from 26.67 days at 20°C to 10.25 days at 35°C. The oviposition period was 4.16, 4.6, 4.99, 4.04 and 3.31 days at 20, 25, 28, 30 and 35°C, respectively, with females laying an average of 56.37, 65.45, 98.59, 57.44 and 33.86 eggs, respectively, at these five temperatures. Life table data were analyzed using an age-stage, two-sex life table method. The intrinsic rate of increase (r=0.262 day-1), finite rate of increase (λ=1.3 day-1) and net reproductive rate (R0=49.28 offspring/individual) were greatest at 28°C. The shortest mean generation time (T=12.17 day) was recorded at 35°C. The results of the current study indicated that temperature is one of the most important factors on life table parameters of T. busseolae. Also the optimum temperature for population growth of this parasitoid was 28°C, therefore this temperature suggests for mass rearing of T. busseolae.

Snow trout (S. zarudnyi) is a commercial, ecological and biological valuable species which is native to the southeastern Iran (Sistan). In this study, 41 samples of Snow trout were caught by gill net from Chah nimeh reservoirs, Sistan and Baluchestan Province, and their biological characteristic were investigated. The results showed that the average weight and length of fish were 121.70±57.07g and 22.35± 3.49cm, respectively. The sexual ratio in Snow trout was 1:1.16 (male: female), and the gonadosomatic Index (GSI) of female was 1.08±0.74%. Moreover, the maximum and minimum percentage of GSI was reported in March (1.75%) and May (0.84%), respectively. The changes in the percentage of GSI indicated that the sexual maturity and breeding season of this fish happened in March. The average relative and absolute fecundity recorded was 33140 ± 1905.65 egg/kg and 26964±1001/97 eggs, respectively. The condition factor (CF) was 1.01±0.12 %, and the maximum and minimum amount of CF was reported in March and May, 1.30% and 0.76%, respectively. The relative gut length (RLG), as the ratio of intestine length to body length was 1.73±0.30. Consequently, considering the amount of RLG which was more than one, Snow trout categorized as omnivorous with herbivorous tendency. The average of feeding intensity (IF) was 180.64±108.99%, and the maximum and minimum of IF was found in May and February, 480.54 and 43.02%, respectively. Finally, the relationship between the length and weight for the species was recorded as W=0.0058L3.177 with r=0.98. The b-value as coefficient of WLR indicates that the growth of Snow trout is isometric.

The melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is one of the most important pests causes damage to vegetable both in fields and greenhouses. The biological characteristics related to the efficiency of natural enemies are considered as quality control indices for preliminary screening, prior to release of biological control agents. In this study some biological characters including parasitism rate, emergence rate, and sex ratio of a sexual strain of the parasitoid wasp, Lysiphlebus fabarum (Marshall), was evaluated for individuals that were reared on different stages of A. gossypii. Furthermore, important factors related to offspring fitness (body length, developmental time, fecundity, and longevity) were surveyed. Results revealed that, L. fabarum could successfully parasitize all the nymphal instars of the melon aphid. With the exception of egg size, all other characteristics were significantly affected by host stage. Wasps emerged from the second and third instars had higher fitness than the other stages. Conseuently, L. fabarum may be considered as an effective biological control agent of the melon aphid, although these results need to be confirmed by further field and greenhouse studies.

In superparasitism, a host is parasitized by one or more conspecific females, a phenomenon resulting in immature competition within the host’s body. In the present study, the competition between sexual and asexual strains of the parasitoid wasp, Lysiphlebus fabarum (Marshall) (Braconidae: Aphidiinae), was studied in simultaneous and successive introductions. The biological traits by both strains were determined in surviving individuals of superparasitized aphids as well. For this purpose, eight wasp females of each strain were introduced into 40 second instar of black bean aphid, Aphis fabae Scopoli, simultaneously or by a 24-hour priority. Our results revealed that the early introduction of each strain had a significant effect on the number of emerging adults of that strain. However, in simultaneous introduction, a greater number of sexual progeny emerged than asexual ones. The development time of sexual progeny was significantly decreased when their females were introduced earlier into the host aphids. Other morphological and biological traits (hind tibia length, head width, ovary area, egg load and egg size) of surviving individuals of superparasitized aphids were not affected by the oviposition sequence of the strains. The findings showed that sexual L. fabarum females were successful in competition with asexual females, the superiority of which could be more important in a host limitation conditions.

The cotton mealybug, Phenacoccus solenopsis Tinsley is one of the important pests of Malvaceae plants that has caused serious damage to China rose Hibiscus rosa-sinensis in Khuzestan province recently. Mean pre-imaginal duration of female P.solenopsis at 20, 25 and 35 °C (65±5% R.H. and 14:10 L: D) were 19.02, 16.6 and 13.54 days, respectively. Mean pre-imaginal mortality were 26.94, 32.72 and 39.12 % at above mentioned temperatures, respectively. One the same three temperatures, mean female longevities were 41.94, 33.8 and 24.6 days, mean daily nymph production were 13.9, 12.06 and 15.12 nymphs, mean total nymph production were 389.68, 318.23 and 214.45 nymphs, mean sex ratio were 70, 71 and 89% and intrinsic rate of increase were0.157, 0.181 and 0.207 most suitable temperature for developmental reproduction of P. solenopsis.
mean total nymph production were 389.68, 318.23 and 214.45 nymphs, mean sex ratio were 70, 71 and 89% and intrinsic rate of increase were0.157, 0.181 and 0.207 most suitable temperature for developmental reproduction of P. solenopsis.

The Heart moth, Dicycla oo (L.) (Lepidoptera: Noctuidae), attacked a part of oak forests in Fars province of Iran in recent years. The larvae severely feed on buds and sprouts and cause the tree to be defoliated from leaves. The pest biological characteristic was studied in the Moordak region of the Kazeroon district during 2004-2007. The results showed that the pest had only one generation in a year. The life of the pest in egg stage was spent beneath the egg scales which had the same color to the oak barks in a part of spring, whole summer and winter. The neonate larvae appeared on the swelling buds from the first half of the March. The duration of embryonic period, larval stages, pre-pupae, pupae and adult longevity took long (320±8.37), (25±2.12), (3±0.34), (8±0.84), and (10±0.71) days respectively. The sex ratio was estimated 1:1 in laboratory and field conditions. The male and female adult longevity was determined 7 and 9 days, respectively. The first moths appeared in the late of April. The peak of moth’s flight occurred on 30th April to 9th May. The morphological characteristics including oviposition rate, body dimensions, head capsule width, pupae body dimensions, and adults were measured. The Male and female moths after forming was sent to Dr. Michael Fibiger in Denmark for confirmed of genus and species.

Indian meal moth Plodia interpunctella، (Lep.: Pyralidae) is one of the main pests of stored figs in Iran. The effects of different temperatures (15، 20، 25، 30، 35° C) on the biological characteristics of this pest at laboratory conditions (16:8 L: D، 60±5 % Rh) on dried fig were studied. Mean incubation period were estimated 14. 44، 6. 70، 3. 27، 3. 30، 4. 26 days respectively. Total larval developmental time were determined 70. 79، 42. 60، 34. 61، 32. 2، 27. 77 days and duration of pre-pupal and pupal stages were estimated 9، 4. 36، 1. 44، 1. 31، 1. 23 and 15. 92، 12. 44، 7. 29، 5. 77، 3. 34 respectively. Mean adult longevity were estimated 12. 62، 12. 38، 7. 04، 7. 65، 6. 73 for female and 14، 12. 37، 7، 7. 03، 6. 33 for parameters. Developmental rate were highest on 35° C. The result showed that high temperature promote rapid development of P. interpunctella on dried figs.

In this study, the effect of host diet on biological characteristics and life table parameters of Habrobracon hebetor Say (Hymenoptera: Braconidae) against the Mediterranean flour moth, Ephestia kuehniella (Zeller) was studied in the laboratory. The diets used were wheat, barley, rice, soybean+wheat, soybean and corn. The prasitoids were studied for three generations. The developmental periods of the female parasitoid in third generation were 11.24, 12.09, 11.60, 11.62, 11.17 and 12.44 days on above mentioned diets, respectively. Total preadult survivals of parasitoid on aforementioned diets in third generation were 0.71, 0.66, 0.74, 0.87, 0.78 and 0.71%, respectively. Sex ratio (% female) of parasitoid in the third generation on larvae fed by aforementioned diets were 35.86, 48.34, 20.5, 31.31, 36.55 and 35.04%, respectively. On above diets, and in third generation, female parasitoid longevity were 39.60, 34.03, 33.53, 28.96, 33.86 and 38.80 days, mean total eggs were 921.88, 708.68, 702.46, 548.77, 505.96 and 597.76 eggs, and intrinsic rate of increase were 0.267, 0.255, 0.216, 0.248, 0.257 and 0.228, respectively. In total wheat regime is recommended as the best regime of Mediterranean flour moth for development and reproduction of H.hebetor.

The Indian meal moth, Plodia interpunctella (Hübner) (Lep., Pyralidae) is one of the serious pests of stored date in Iran and many parts of the world. Biology of this pest on three cultivars of date was studied. The experiments were conducted in laboratory conditions at temperature of 27±2 ºC, 45±5% relative humidity and a photoperiod of 16L:8D hours. Mean incubation period were estimated 3.10, 3.27 and 2.67 days respectively and mean larval developmental time were estimated 37.85, 43.01 and 48.0 days on Zahedi, Shahabi and Kabkab cultivars respectively. There was significant difference between mean larval developmental time and incubation period on different cultivars. Mean period of pupa on Zahedi, Shahabi and Kabkab cultivars were estimated 7.47, 8.01 and 7.19 days respectively. No significant difference was observed between mean period of pupa moths developed in Zahedi and Kabkab cultivars but pupal period was significantly different on Shahabi cultivars. Mean adult longevity on Zahedi, Shahabi and Kabkab cultivars were estimated 8.04, 8.37 and 7.72 days respectively. There was no significant difference between mean adult longevity on different cultivars of date.

In order to investigate the effects of mineral compounds as complementary nutrients for silkworm, Bombyx mori, an experiment was performed in CRD with five treatments including: 1%, 5% and10% concentrations of multi-mineral mixtures (nitrogen, phosphorus and potassium) with normal and distilled water treatments as controls. The larvae were fed by mulberry leaves from Shien Ichenoise variety up to the fourth instar. From the beginning of the fourth instar, the supplementary leaves were used once a day. The supplementation of the leaves was done by spraying the solution on them. The amount of total protein and uric acid in haemolymph of a 6-day 5th instar larva was measured. The value of total protein compared to controls had significantly increased in all mineral treatments. The larvae's weight on the third day of the fifth instar had significant difference from controls, but the weight of silk gland did not show such a difference. However, uric acid of insect's blood demonstrated little differences but it showed no statistical significant differences from that in controlled insects. Despite this, the weight of cocoon, cocoon shell and pupa also had significant differences compared to controls, where this enhancement was higher in females than in males. Due to increase of the number of eggs, statistically there was a significant difference between the 10% treatment and others. The compounds had decreased the hatching percentage.