a. a. zamani

Potato (Solanum tuberosum L.) is a vital crop of great global importance. Common scab is one of the most destructive diseases affecting the quality and yield of potatoes. Effective disease management strategies for potatoes include crop management, crop rotation, seed certification, natural and chemical pesticides, disease prediction models, germplasm screening, and the development of resistant varieties. Sulfur fertilization improves potato resistance to common scab, possibly by decreasing the soil pH. Applying sulfur and Thiobacillus bacteria in alkaline and calcareous soils has improved nutrient solubility and reduced damage caused by common potato scab disease.

An experiment was conducted to investigate the effects of sulfur and Thiobacillus on tuber yield and the common scab disease index under field conditions. The farm had a history of natural and uniform infection with potato scab disease. The treatments included: 1- control (no use of Thiobacillus and sulfur), 2- application of Thiobacillus, 3- granular sulfur, 4- liquid sulfur, 5- Thiobacillus+granular sulfur, and 6- Thiobacillus+granular sulfur+liquid sulfur. The experiment was conducted using a randomized complete block design with four replications.

Analysis of variance indicated that the application of sulfur and Thiobacillus significantly affected tuber yield and the common scab disease index. However, there was no significant difference in the mean number of plants among the experimental treatments. Regarding the mean number of tubers, the count increased from 104 in the control group to 135.75 in the treatment with granular sulfur+liquid sulfur+Thiobacillus treatment. This combination significantly increased tuber weight by approximately 4 kg compared to the control. Regarding the average number of tubers per plant, the treatments of granular sulfur+liquid sulfur+Thiobacillus and granular sulfur+Thiobacillus showed a significant difference compared to the control, increasing the number of tubers by 13.06% and 8.10%, respectively. Both treatments also significantly increased the mean tuber weight per plant by 19.69% and 16.21%, respectively, compared to the control. The percentage and disease index varied under the influence of the experimental treatments. The lowest disease index on potato tubers was associated with the simultaneous application of granular sulfur+liquid sulfur+Thiobacillus, followed by liquid sulfur alone. The decrease in the disease index on potato tubers can be attributed to the reduction in pH resulting from sulfur application. This study demonstrated that the simultaneous application of sulfur and Thiobacillus can effectively lower soil pH.

In conclusion, the application of sulfur and Thiobacillus bacteria enhances the yield and quality of potato tubers by improving soil conditions and plant nutrition. The forms of sulfur used played a crucial role in disease management; liquid sulfur, either alone or in combination with other treatments, significantly reduced disease severity. Liquid sulfur contains sulfate forms and has a pH of approximately one. Additionally, its liquid form allows for better penetration into soil pores and does not require soil microbial processes to alter pH. In contrast, powdered and granular forms of sulfur must be converted to sulfate forms by sulfur-oxidizing bacteria such as Thiobacillus. This conversion process is lengthy and gradually reduces soil pH over time. In the present study, various forms of sulfur, especially the liquid form, effectively reduced soil pH, although it did not lower it enough to classify the soil as acidic. It is important to note that the study's soil was calcareous, which has buffering properties that prevent drastic pH changes. Moreover, the effect of sulfur is not solely dependent on pH; even low amounts or specific forms of sulfur can significantly reduce common potato scabs without altering soil pH. This phenomenon may be due to the conversion of sulfur into toxic forms for microbes, such as hydrogen sulfide (H2S).

Bean (Phaseolus vulgaris L.) (Fabaceae) is one of the most cultivated plants of legumes in most countries. Several of insects with piercing-sucking mouthparts such as thrips, leafhopper, aphids, and plant bugs are as pest on beans. Thrips can attack beans from the seedlings emerge through to flowering, but it is the damage some do during flowering that has the greatest impact. Thrips tabaci Lindeman 1889, the onion thrips is a cosmopolitan species. It has hundreds of host plants but of these, the economically most important crop plants are onion, cabbage, tobacco, pepper, bean and tomato. Here, population fluctuation and spatial distribution of thrips was investigated in the bean fields of Sanandaj county (Kurdistan province, west of Iran).

Sampling was done from bean leaves from two leaves stage until ending growing season  in the bean fields (bean Canyon variety) located in Arandan village (N 35° 23' 10.96", E 46° 54' 53.16", alt. 1660 m), Sanandaj county during the years 2022 and 2023. Bean leaf was selected as sampling unit. Sampling was done weekly and four rows were sampled each time. A systematic sampling pattern was used to collect the samples. In this way, in the selected rows, 24 plants at the beginning and end of each row were ignored, and the 25th plant of each row was the first plant on which thrips were counted. After that, 24 plants were left and counting was done on the 25th plant after the first plant. In this way, 25, 50, 75, 100, 125, 150, 175, 200, 225, 250, 275, 300 and 325 plants were sampled in each row. Weekly sampling was done in a similar style, but each time, different rows of crops were selected for sampling. Sampling was done weekly, and for this purpose lower, middle and upper leaves were selected from each bean and the leaves were shaken on a white tray and then the thrips were put into Eppendorf containing ethyl alcohol 75%. In order to accurately count thrips, by using a stereomicroscope, some samples were separated and microscopic slides were prepared from some samples and finally the number of samples was recorded. Spatial distribution of adults of thrips was estimated using Taylor’s power law and Iwao’s patchiness regression methods.

The results showed that the population of onion thrips was observed from July and gradually increased and in 2022 its maximum was in the first week of August with an average of 11.65 ± 0.14 thrips and in 2023 its maximum was in the end of week of August with an average of 11.29 ± 0.23 thrips at the sampling unit. In addition, the highest mean number of onion thrips was observed with a significant difference in the lower leaves compared to the middle and upper leaves. The results of the spatial distribution of the pest showed that based on the variance-to-mean ratio, Taylor’s power law and Iwao’s patchiness regression methods, the spatial distribution of onion thrips was clumped, randomized and clumped, respectively. In general, the results showed that the peak of population of onion thrips reaches in early of August. Furthermore, based on goodness of fit, the Iwao’s patchiness method was more suitable than the Taylor’s power law method for estimating the spatial distribution of the pest.

It can be concluded that, at the beginning of the growing season of beans in the field, a low population of onion thrips was activated, and gradually with the warming of the weather and the change of the growing stages of the beans, the population of the pest in the field increased, so that the largest population of onion thrips were observed in the first week of August. In addition, based on the sampling, the highest average number of onion thrips was observed in the lower leaves of beans compared to the middle and upper leaves. The relationship between population fluctuations of onion thrips with average positive temperature was obtained. In examining the spatial distribution pattern with the Iwao’s patchiness method, it was found that the spatial distribution of onion thrips is uniform. Considering the high activity and damage caused by onion thrips on various crops, especially on beans, it is necessary and important to conduct more studies on its various characteristics in various regions and crops of Kurdistan province so that a suitable management plan can be developed to control this pest.

Camelina, Camelina sativa (L.) Crantz (Brassicaceae) is an oilseed plant that was imported to Iran in 2015. Camelina is a cold-tolerant oilseed crop with minimal input requirements. In this study, the population density of Thrips tabaci Lindeman and its effect on the yield of different lines of camelina were investigated under field conditions. In this regard, 136 lines of camelina cultivated in the farm and for sampling, each plant was considered as a sampling unit and the number of thrips was counted on each plant after tapping. The number of healthy and injured capsules and seeds were also counted in each line with three replications. The results showed that yield decreased with increasing percentage of injured capsules. In addition, the percentage of damaged seeds was negatively correlated with the yield of camelina lines and the percentage of injured capsules was positively correlated with the percentage of damaged seeds. The results of linear regression showed that the relationship between thrips population density and yield and percentage of damaged seeds was not significant, while a positive and significant relationship was observed between thrips population density and percentage of injured capsules, meaning that with increasing thrips density, percentage of injured capsules increased, as well. Based on the findings, line 54 was recognized as the most resistant line against T. tabaci which was a semi-sensitive, resistant and tolerant line in term of antixenosis, antibiosis and tolerance mechanisms, respectively.

Oak thrips, Liothrips pragensis Uzel is found on oak trees in Zagros forests. In this study, population fluctuation and spatial distribution of this species were investigated in oak forests of Javanrud county (Kermanshah province), in 2021. Oak leaves were selected as the sampling unit. Sampling was performed every week from five different areas, so leaves were shaken on a white plastic tray and thrips specimens with a soft brush were transferred into Eppendorf tubes containing 75% alcohol. The results showed that the activity of oak thrips in all five studied areas was occurred on May and their activity and density gradually decreased until it reached its lowest level in September. The highest population density of oak thrips was observed on May with an average of 2.93 ± 0.56, 2.23 ± 0.47, 2.23 ± 0.34, and 0.90 ± 0.28 thrips per sample unit, in Sefid Barg, Bileei, Cheshme Miran and Helanie areas, respectively. However, the highest density was obtained in Hori Abad region in June with an average of 2.06 ± 0.43 thrips per sampling unit. The results of spatial distribution showed that the spatial distribution of oak thrips based on Taylor’s power law and Iwao’s methods was random and aggregated, respectively. Furthermore, based on goodness of fit, the Iwao’s patchiness method was more suitable than the Taylor’s power law method for estimating the spatial distribution of the pest.

Worldwide, Iran is the first producer of pistachio, which is one of the most economically important agricultural products for this country. Idiocerus stali Fieber (Hemiptera: Cicadellidae) is one of the most important pests of this plant. Adults and nymphs pest feed on leaf tissues and fruit clusters, and they cause damage by sucking the sap. This pest has one generation per year. In this research, population fluctuations of the pistachio leafhopper associated to the temperature and humidity changes and its spatial distribution, using both statistical and geostatistical methods were studied in 2018-2019. The spatial distribution of all life stages in both years was cumulative according to Iwao model, whereas considering Taylorchr('39')s power law model it was cumulative in 2018 and random in 2019. Considering coefficientschr('39') values, both models of Taylorchr('39')s power law (R2= 0.93) and Iwao model (R2= 0.92) are appropriate for estimating the type of spatial distribution for this pest, however, Taylor model showed a better data fitting. Concerning geostatistics models, Kriging interpolation method was more accurate than Inverse Distance Weighting (IDW) and it was used to produce pest distribution maps. The movement process of adults, nymphs, and the sites of laying areas per week was precisely determined. Hence, contamination foci can be identified and used to apply appropriate management methods at the right time at a low cost.

Pistachio is one of the most important and economical agricultural products of Iran from the standpoint of exportation. Iran is the first largest producer of pistachio in the world. Due to expansion of pistachio orchards in Kermanshah province, this research was done in 2017, 2018 and 2019 to identify the pests of these trees. Different sampling methods such as direct collection, rearing in laboratory, sweep in net, white tray, light trap, aspirators were used to collect insects. Finally, 13 species of insect pests including Sulamicerus stali Fieber, Agonoscena pistaciae Burckhardt and Lauterer, Forda hirsuta Mordvilko, Anapulvinaria pistaciae Bodenheimer, Lepidosaphes pistaciae Archangelskaya, Acrosternum heegeri Fieber, Polydrosus davatchii Hoffman, Anthaxia judinae Stepanov, Carphoborus perrisi Chapuis, Recurvaria pistaciicola Danilewski, Eurytoma plontnikovi Nikolskaya were reported on pistachio trees in pistachio orchards. Labidostomis luristanica Warchalowski (Col .: Chrysomelidae) was first report from Kermanshah province and Thrips minutissimus Linnaeus (Thy .: Thripidae) is reported for the first time on pistachio trees.

Cucumber, Cucumis sativus is a widely cultivated plant in the Cucurbitaceae family, which is used as a vegetable. Various pests at different stages of growth cause economic damage to it. Lesser pumpkin fly, Dacus ciliatus Loew (Diptera: Tephritidae) could be considered as one of the most important pests of cucurbits worldwide, which direct feeding of larva on fruit making it unusable. Farmers often spray their fields with various pesticides and in some cases is not very effective. Owing to many problems in the chemical control of fruit flies, using resistant plants is one of the most important components in integrated pest management. Host plant resistance is an important component for the management of lesser pumpkin fly, due to difficulties associated with its chemical and biological control. Resistant genotypes can be used to manage this pest.

Seeds were sown in 2018 with ten replicates (blocks) for each genotype following a completely randomized block design. The area of each bed was 4 m × 4 m and the plant-to-plant distance was maintained at 50 cm with a drip irrigation system. All the recommended agronomic practices (e.g. weeding, fertilization, hoeing, etc.) were performed equally in each experimental bed. The infested fruits were sorted and the percent fruit infestation was calculated. Different genotypes by degree of infection into completely resistant (no contamination), very resistant (1-10%), resistant (11-20%), relatively resistant (21-50%), susceptible (51-75%) and high susceptible (100-75%) were sorted. In this experiment, morphological and biochemical characteristics related to resistance were measured in six different genotypes of cucumber (Hayek, Surina, Maximus, Kish, Armenian cucumber, and a local genotype of Kermanshah). The effect of these traits on fruit infestation and larval density was determined. Ten fresh fruits were selected from each genotype and fruit length, fruit diameter, fruit rind thickness, and rind trichomes density were measured and recorded. To measure biochemical traits two fresh fruits from each genotype were selected and the number of chemical compounds such as phenols, flavonoids, tannins, and total alkaloids was measured.  Percentage of fruit infestation, larval density, biophysical, and biochemical traits values were analyzed by Two-way analysis of variance using SPSS 24 software. The means of significant parameters, among tested genotypes were compared using Tukey’s tests for paired comparisons at the probability level of 5%. Correlations between biophysical and biochemical fruit traits and fruit fly parameters (percent fruit infestation and larval density per fruit) were determined using correlation analysis at the 95% significance level.

The larval density per fruit increased with an increase in percentage of fruit infestation and there was a significant positive correlation between percent fruit infestation and larval density per fruit. Among the studied genotypes, Hayek resistant, Surina, Maximus, and Kish moderately resistant, Armenian cucumber susceptible and local genotype was highly susceptible. Phenol content (r = 0.77), tannin (r = 0.89), total alkaloids (r = 0.93) and flavonoids (r = 0.87) were statistically correlated with the percentage of fruit infestation. The percent fruit infestation had significant positive correlation with fruit length (r = 0.55), fruit diameter (r = 0.48), fruit rind trichomes density (r = 0.81) and rind thickness (r = 0.87). Maximum variation in fruit infestation (86.50%) and larval density (63.70%) was explained by the alkaloids. Stepwise regression analysis of our data showed that the highest variation in fruit infestation (75.30) and larval density (61.40) was explained by the trichomes density. Therefore, it can be argued that the reduction of fruit fly infestation on resistant cultivars could be due to physical and biochemical characteristics.

Reduction of fruit fly infestations on resistant genotypes could be due to antibiosis (adverse effect of host plant on the development and reproduction of insect pests, which feed on the resistant plant) and antixenosis (operates by disrupting normal arthropod behavior). Our results suggest that biochemical and biophysical fruit traits could contribute to these mechanisms of resistance. Rind thickness, rind trichomes density, total alkaloids, and tannin were playing an important role in pest resistance. In summary, certain biochemical (tannins, phenols, alkaloids, flavonoid) and biophysical (rind thickness, fruit rind trichomes density, fruit length, fruit diameter) traits were linked to the resistance of cucumber against D. ciliatus and therefore can be used as marker traits in plant breeding programs to select resistant genotypes. By using Hayek genotypes, which have less susceptibility to the lesser pumpkin fly, farmers can produce safe products with less residual insecticides.

Stethorus gilvifrons is one of the most important monophagus predators of Tetranychus urticae. In this study, demographic parameters of S. gilvifrons were compared between solitary and group (5 pairs of the predator) rearing systems feeding on different developmental stage of T. uricae at 27±1°C temperature, 60±10% RH and a photoperiod of 16:8 h. L:D. In order to start experiments, 120 eggs (< 24 h. old) were selected randomly from the laboratory culture of S. gilvifrons for each treatment. The data were analyzed based on the age-stage, two-sex life table theory. Developmental times of the incubation period, larval, pupal, and total immature stages of S. gilvifrons were 3.92±0.08, 6.52±0.14, 2.98±0.06, 13.59±0.14 days, respectively, in solitary rearing system. In the case of group rearing, developmental time of S. gilvifrons for the mentioned developmental stages were 3.51±0.06, 6.85±0.21, 2.85±0.11, and 13.18±0.21 days, respectively. Moreover, estimated values of intrinsic rate of increase (r), finite rate of increase (λ), mean generation times (T), net reproductive rate (R0) and Gross reproduction rate (GRR) were (0.1219; 0.1455 day-1), (1.1297; 1.1567 day-1), (30.23; 19.88 day-1), (39.92; 18.08 offspring/individual), (265.38; 88.37 females/female/generation), respectively in solitary and group rearing systems. According to the obtained results, demographic parameters of the S. gilvifrons were affected by the number of the individuals in the arena, and population growth was less in the group rearing system, in comparison with solitary rearing condition. These findings can be useful for improving mass rearing of S. gilvifrons and biological control programs of Tetranychids.

Mercury (Hg) contamination in marine ecosystems is a major threat to human health in the developing countries like Iran. The main route of mercury exposure is from consumption of fish and seafood. Upon entering mercury in human bodies, Hg is converted into methyl mercury, which may lead to serious implications including neurological disorders, reproductive abnormalities, kidney failure, emotional instability, gingivitis and tremors. Therefore, research on mercury concentrations in marine ecosystems (water and fishes) can be help to protect human health and reduce the risks of mercury contamination.
In this study in order to evaluate the concentrations of Hg in water and fish, water samples (36 stations), fish tissue livers (n=33) and muscles (n=33) of four fish species from the Caspian Sea (southern coasts) were collected and analyzed. For determination of Hg in water and fish samples, Voltammetry and GF-AAS techniques were used, respectively.
The results showed that the average Hg concentration detected in water samples was 1.657 (μg/L) and in fish muscle and liver tissues were 68.636 and 125.606 (μg/g.dw), respectively. The bioaccumulation factor showed that mercury concentrations from water to fish are in the range of 14 to 80 times. The highest levels of mercury in water and fish were observed in the southwest coasts of the Caspian Sea.
According to USEPA and SPPA (China) standards, more than 58 % of the water samples collected from the southern coasts of the Sea was polluted by mercury. However, the average concentrations of mercury in fish samples were less than the standards by WHO and EPA.

During a study on the pests of button mushrooms in the city of Kermanshah، the sphaerocerid species of Pullimosina heteroneura (Haliday) was collected from mushroom culture media. This species is a new record for the Iranian insect fauna.