فصلنامه مطالعات حفاظت گیاهان
سال سی و هفتم شماره 4 (زمستان 1402)

Pistachio (Pistacia vera L.) is the most important horticultural crop cultivated extensively in central areas of Iran and an economically important nut that ranks the first among the agricultural export commodities in Iran. The annual exportation of this nut crop reaches to 100,000 tonnes that ranks the second after the oil in revenue income of the country. Kerman province is the most important pistachio producing province in Iran. The highest acreage of the pistachio producing lands in this province are allocated to Kaleghochi, Ahmadaghai, Ohadi and Akbari cultivars, respectively. Not to mention that these are the most commonly cultivated pistachio cultivars in Iran. The pistachio trees are attacked by many different insect pests. The pistachio green stink-bug, Brachynema signatum (Hemiptera: Pentatomidae) is a key pest of pistachio in Iran. The adults and nymphs of this insect feed on the developing fruits of pistachio and cause significant damages in the form of pericarp lesions that result to the nut drop. The pistachio green stink-bug is also a vector of thepathogenic fungus, Nematospora coryli Peglion that causes the formation of corky appearance and somewhat bitter and distasteful smell of pistachio endocarp. In the pistachio producing areas of Iran, this pest is present in the pistachio orchards throughout the year and can produce four to five generations per year in Kerman province. Since the host plant can affect the growth, reproduction and survival of herbivorous insects, therefore evaluating the effects of host plant on the growth and reproductive characteristics of insect pest could be used in its integrated pest management programs. These effects could be evaluated by calculating the demographic parameters, especially the intrinsic rate of increase of the insect pest (rm) on preferred host plant, reminded that the demographic parameters are affected by the quality of host plant and are very useful indicators for evaluation the suitability of host plants to insect pests. This research was conducted to study a preferred natural diet (fresh kernels of pistachio) on developmental time, fecundity, survival rate, and life table parameters of pistachio green stink bug, Brachynema signatum (Hemiptera: Pentatomidae). This research was conducted to study a preferred natural diet (fresh kernels of pistachio) on developmental time, fecundity, survival rate, and life table parameters of pistachio green stink bug, Brachynema signatum (Hemiptera: Pentatomidae).

Insects reared on fresh kernels of pistachio head ram species in the growth chamber at 27 ± 1 ˚C, 65 ± 5% RH and a photoperiod 16: 8 h (L: D) and the parameters of age-stage, two sex life table of the insect were determined. The life table study was done with 100 identical eggs of the same age. After hatching, instar nymphs were fed with fresh kernels of pistachio head ram species every day. The data of Life table were analyzed according to the theory age-stage, two sex life table.

The total development time from egg to the death of adults was 83.85 days. The survival rate from newly nymph to adult stages was 34%. Females started to oviposition on day 36, reached its pick on day 44, and then gradually declined until reached zero on day 86 of the insect’s life span. The intrinsic rate of natural increase of population (rm) and the finite rate of population increase (λ) were 0.084 ± 0.0030 and 51.55±0.387 (female/ female/ day) respectively. Gross (GRR) and net reproduction rate (R0) were equal to 140.14 ± 15.17 and 78.78 ± 11.18 female eggs. Mean generation time (T) was 1.088±0.003 days.

The fertility life table can be constructed for analyzing and understanding the effect of external factors and host plants on the growth, survival, reproduction, and intrinsic rate of increase of insect populations. Host plant quality is an effective factor on the fecundity and population growth rate of herbivorous insects. Analysis of age-stage, two-sex life table and its parameters obtained in this study showed that stink bug had an appropriate development on natural diet. These results could help us to understand the B. signatum population dynamics under field conditions. The results could also help us make better management decisions in integrated pest management (IPM) programs for economically important crop, Pistachio.

Potato tuber moth, Phthorimaea operculella is an important pest of potatoes which annually impose economic loss in potato production especially in stored places. Chemical control with spray in farms and fumigation in storages is a conventional method for depressing the population of this pest. In addition, with harmful effects of synthetic pesticides on environment and human health, developing resistant population of insects, compel researchers and plant protection institutions to utilizing new safe control methods. Delaying the resistance by keeping effectiveness of pesticides by using synergists and sublethal concentrations is a resistance management method. Bacillus thuringiensis is an effective microbial control agent against some insects. Its effectiveness decreased because of developing resistance in some population of insects. Combination of Bt with some botanical biopesticides increases its efficiency that reported in many studies. In this study combination of B. thuringiensis with hexane, ethyl acetate and methanol extracts of Celery, Apium graveolens were investigated on mortality and some biological parameters of PTM. Celery is a biennial plant in the apiaceae family, which is rich in some compounds such as phenolic and flavonoids. These compounds could affect biology and physiology of insects. Combination of sublethal concentrations of Bt with extracts of celery subjected for study of their effects on mortality, synergistic effects and some biological parameters on PTM larvae in this paper.

Potato tuber moth colony established by preparing larvae from a health colony in department of plant protection, Azarbaijan Shahid Madani university. Larva reared on potato tubers in plastic containers. Rearing carried out in controlled condition of 26±2ºC, 60% RH and a photoperiod of 16:8 (L: D) hrs.Foliage of celery after well washing with distilled water, dried in shadow in laboratory condition. Coarsely powdered dry plants used for extraction. Extraction carried out using the maceration method with three solvents, hexane, ethyl acetate and methanol respectively. Sub-lethal concentrations of both agents, including LC10, LC30 and LC50, individually and in combination, were assayed by the oral bioassay method. The same age and size of potato leaves were impregnated with sub-lethal concentrations of both experimental materials using the dipping method. The first larval instars of PTM were transferred on treated leaves, and mortality was recorded in 48, 96 and 144 hours’ intervals. Larval developmental period and adult’s emergence as an important biological parameterrecorded in all treatments. In addition, the inhibitory activity of extracts on α-amylase and protease enzyme of PTM larva was considered.Inhibitory activity of celery extracts in two concentrations 1 and 10%, on PTM larvae alpha-amylase activity was assayed by the dinitrosalicylic acid procedure, using 1% soluble starch as a substrate described by Bernfeld, (1955). And protease inhibitory activity assayed using azocasein as substrate, with comparing enzyme activity in controls and present of extracts in reactions.All experiments were replicated three times. On-way ANOVA analysis of variance in random design was used for statistical analysis. Duncan’s multiple range tests used for comparing means. For determining the synergistic, additive or antagonistic effects of combinations, chi-square test conducted between observed and expected results (df=1).

The results revealed that ethyl acetate extract of celery in combination with Bt synergistically increased the mortality of larvae. Compared to the control, the combination of methanolic extract with Bt didn’t affect larval mortality. However, the combination of sub-lethal concentrations significantly increased larval life span compared with the control and adult emergence decreased especially in LC50 combinations. Increasing the mortality with exposure time progressing, observed in all combinations and the most larval mortality recorded in 144 hours’ exposure time. Ethylacetate extract of celery alone and in combination with Bt more than other solvents affected biological parameters of PTM. Extracts in the concentration of 10 percent in reactions inhibited α-amylase and protease activity of PTM larvae by 27.97-37.77 and 11.48-25.51 percent, respectively.Numerous researchers have reported increased efficiency of Bt in combination with other plant extracts for controlling various insects. The observed synergistic effects can be attributed to factors such as disrupting midgut properties, inhibiting digestive enzyme activity, and disrupting the insect's immune system by plant extracts.Inhibitory activity of celery extracts on digestive enzymes activity of PTM larva, well documented in this research which is in alignment with other reports. Effects on larval life span that with prolonging it affects population dynamics of insect pests, reported in same studies. This biological effect has adverse effect on development and physiology of insects and asynchronies developmental stage with environmental variations which finally decrease the population of next generations or overwintering insect’s density. Adults and pupa emergence percentage decreased in combination of Bt with celery extracts that same results were reported in other researches.

This study aims to determine the effects of different extracts (prepared by different solvents) of celery in combination with Bt on potato tuber moth larvae. Effects of different solvents in separating effective compounds on PTM, was not same. In certain instances, the methanol extract of celery showed a minor effect in enhancing the potency of Bt. However, strong synergistic effects were observed with ethyl acetate and hexane extracts at various integrated concentrations. Time also played a crucial role in achieving the desired mortality results, with mortality and synergistic effects increasing over time in all extract combinations with Bt. Particularly, towards the end of the exposure period, a synergistic effect was notably observed in all integrations involving ethyl acetate extract of celery.In addition, with mortality, larval developmental period also affected by combinations. Increasing in life span observed in all treatments with different ratios. Adult emergence decreased strongly in different treatments and this is so important in decreasing the population of PTM. Because of importance of Bt as an effective and safe insecticide and increasing the resistance by different pests such as PTM, management of insects in integrated programs using plant extracts will improve the efficiency of Bt. Decreasing the sprayed concentrations in combination with other control methods are two important resistance management toll in IPM programs. Celery is a potent plant for this goal and additional studies are needed.

 One of the important bacterial diseases of stone-fruit trees is canker caused by Pseudomonas syringae pv. syringae (Pss). This pathogen employs a vast range of pathogenic and virulence factors during its interaction with its host in order to induce disease symptoms. To control the bacterial canker disease, various methods such as sanitary measures, selection of resistant cultivars and certified seedlings and chemical component based on copper are used. Application pf plant derivatives such as essential oils and extracts, is one of the compatible management methods in line with environmental goals. Essential oils include a wide range of antimicrobial components and have high efficacy, multiple mechanisms of action, and low toxicity on non-target organisms. The current study aimed to assess the inhibitory and sub-inhibitory effects of six indigenous medicinal essential oils against the causative agent of canker disease in stone fruits. The research evaluated the efficacy of these essential oils in reducing the virulence factors of the disease while identifying the active compounds within the oils. 

The antimicrobial properties of six native plant EOs, namely Thymus transcaspicus, Satureja khuzistanica, Mentha longifolia, Ziziphora clinopodioides, Perorkia abrotanoides, and Artemisia persica were evaluated against Pss bacteria based on disc diffusion assay test and measurement of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Moreover, the effect of essential oils on some virulence factors of pathogen including motility, biofilm, and syringomycine production was investigated in sub-inhibitory concentrations. The effect of selected EOs on the reduction of bacterial pathogenicity on immature cherry fruitlets was also investigated. Finally, the chemical composition of EOs was determined using gas chromatography–mass spectrometry (GC-Ms).

All studied essential oils have different antibacterial effects in interaction with Pss bacteria. EOs of T. transcaspicus and S. khuzistanica showed a significant inhibitory effect with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) value of 1.16 and 2.32 g L-1, respectively against Pss compared with other essential oils and streptomycin antibiotic. Sub-inhibitory concentrations test of EOs showed no significant effect on the growth pathogen. The swarming motility of bacterial cells treated with essential oil decreased by 25-55% and the swimming motility decreased by 18.42 to 35.71% compared with the control. T. transcaspicus and S. khuzistanica within the range of 70-75% showed the strongest inhibitory effect on biofilm formation. Also, in the toxin production test, T. transcaspicus and S.khuzistanica EOs are effective in reducing syringomycin production and increasing the growth of Geotrichum candidum by 1.5 to 1.76 times compared with control (not treatment with EOs). The EOs treatment at MICs reduced the symptoms of the disease. In immature cherries inoculated with Pss bacterium and treated with EO of T. transcaspicus was not observed necrosis symptom. The four selected essential oils tested all had a role in reducing the virulence factors in Pss, and the degree of effectiveness is different depending on the components of the essential oil. The higher the phenolic content in the essential oil, the greater its antimicrobial properties against plant pathogenic bacteria. According to the EOs analysis, thymol in T. transcaspicus, carvacrol in S. khuzistanica, piperitone in M. longifolia, and pulegone in Ziziphora clinopodioides were the major constituent compound. It seems that the highest amounts of compounds in essential oils have a higher antibacterial power. The EOs of T. transcaspicus and S. khuzistanica effectively reduce the pathogenic activity of bacterial cankers agent in stone fruits. ConclusionThe studied plant compounds in sub-inhibition concentration showed acceptable potential in inhibiting pathogenic agents in in vitro tests. Taking into account the growing trend of the general acceptance of natural control compounds in the field of plant diseases, it seems that planning in line with how to use plant products to reduce the consumption of pesticides can be investigated and needs complementary experiments. In order to reduce the spread of bacterial canker symptoms and increase the life span of the tree, the main effective substances (oxygenated monoterpenes) of the essential oils of T. transcaspicus and S. khuzistanica can be used as a model chemical structure for the synthesis of antimicrobial substances using the experts in the field of chemistry and pharmaceuticals. It is suggested to investigate the stability and preservation of antimicrobial properties in laboratory and field conditions.

The genus Malva (family Malvaceae) includes species of herbaceous plants which are often pluriannual and very common in borders and boundaries of cultivated fields, making them proper reservoirs for plant pathogens. They are most commonly used as ornamental plants, although they may be used as a food resource and remedy for various diseases. Common mallow (Malva sylvestris) is the most important Malva species which is used as garden flower as well as widely recognized for food and medicinal purposes.  Malva sylvestris are reported to be affected by several viruses from different genera including malva vein clearing virus (MVCV, Potyvirus), alfalfa mosaic virus (AMV, Alfamovirus), malva-associated soymovirus 1 (MaSV1, Soymovirus) cucumber mosaic virus (CMV, Cucumovirus), and cotton leaf curl Gezira virus (CLCuGeV, Begomovirus). In this study, we attempted to identify important viruses infecting mallow plants and compare mallow isolates with other sequences in the GenBank.

In 2022-2023, twenty samples of mallow plants with viral-like symptoms on the leaves were collected from the urban landscape of Golestan province. Total RNA was extracted by DENAzist Total RNA Isolation Kit from fresh, infected mallow leaves. All samples were analyzed by RT-PCR with specific primer pairs for the detection of CMV, AMV, and MVCV. The amplified fragments in expected size of coat protein (CP) gene of each virus were visualized under UV light in agarose gel after electrophoresis, then amplified fragment of one isolate of each virus was bi-directionally sequenced. Obtained sequences were compared to data available in GenBank. The phylogenetic trees of viruses were constructed based on the nucleotide sequences of the coat protein gene using the neighbor-joining method by MEGA11.

All three viruses were detected in some symptomatic samples collected from Golestan province. The most typical symptoms in positive samples were mosaic, vein clearing, and leaf malformation. Of a total of 20 sampled plants, MVCV, CMV and AMV were detected by RT-PCR in nine, five and two samples, respectively. An amplicon of each virus was selected and sequenced in both directions. BLASTn analysis of the sequenced data confirmed that the PCR-amplified fragments belonged to MVCV, AMV, and CMV. Phylogenetic analysis based on the nucleotide sequence of CP gene of MVCV (n=21) including Iranian and GenBank isolates showed that all isolates are divided into six groups: G1 to G6. All Iranian isolates along with the isolate from the Netherlands were placed in group G5. The phylogenetic tree placed the CMV sequences (n=51) into two distinct phylogroups I and II; the obtained isolate CMV-IR-Ma clustered together with isolates from Iran, Netherlands, South Korea, Japan, China, Hungary, Australia, France and the USA into group II. According to the results of this study, AMV isolates (n=17) can be divided into two groups, I and II. Group I which includes isolates from Canada, China, Italy, Spain, Argentina, Australia and the USA, was divided into six subgroups. The obtained isolate AMV-IR-Ma was clustered in subgroup IB with a Chinese isolate (HZ) and forms a common branch with isolates (Ir-VM, Ir-WS, and Ir-WS2) from Iran. This is the first report of mallow (Malva sylvestris) infection with CMV and AMV in Iran using RT-PCR. In addition, mixed infection with two (MVCV+CMV and MVCV+AMV) or all three viruses (MVCV+CMV+AMV) was also confirmed in some samples. The phylogenetic trees showed that most of the viral isolates were not grouped according to their geographic locations. This suggests the dissemination and spread of these viruses through infected seeds. In Iran, M. sylvestris is a common weed found in fields, waste grounds, roadside verges and gardens. Considering the potential non-persistent aphid transmission as well as mechanical transmission, virus-infected mallows can act as a natural reservoir, thereby posing a threat to other ornamental plants and crops. Since the studied viruses were not detected in the other symptomatic plants, the observed symptoms can be caused by physiological disorders such as nutrient deficiencies, the presence of different viral strains, or other unknown and undetected viral species.

This study provides new knowledge on the diversity and molecular characteristics of viruses in mallow plants (M. sylvestris) affected by the viral disease. The information obtained from this study can be helpful in improving management strategies for disease caused by these viruses in Iran. Albeit M. sylvestris is a host of these viruses, but more comprehensive research on other viral species that may infect this plant need to be conducted. Weed management could be an effective way to eliminate inoculum sources of these viruses.

 Syrian bean-caper is one of the important weeds in orchards, especially pistachio orchards in Kerman. Seed germination is a critical event in determining the success of a weed species in an ecosystem and is regulated by several factors such as temperature, light, soil salinity, moisture and pH. Seed dormancy is the most important factor that prevents seed germination, especially in weeds. Breaking seed dormancy by sulfuric acid scarification is one of the most common methods of stimulating seeds for germination. Temperature is one of the factors controlling the germination and distribution of plants in natural and agricultural ecosystems. All biological events respond to temperature, and all responses can be summarized in three main temperatures. The effects of temperature on plant development are the basis of the models used to predict germination time. The seeds of any species could germinate in a certain temperature range, which is described as the cardinal temperatures (minimum, optimum and maximum) Knowledge of seed germination characteristics, seed dormancy mechanism and response of these phenomena to environmental conditions in weeds, including Syrian bean-caper, can be useful in predicting its spread potential to other areas and its management, so the aim of this study was to identify the methods of dormancy breaking (knowledge of seed dormancy mechanism), the effect of light and alternating temperature on seed germination and also to determine the cardinal germination temperatures of this species.

 To evaluate the effect of some methods on breaking seed dormancy, and to evaluate the effect of alternative temperatures and light on seed germination and to determine the cardinal temperatures of Syrian bean-caper seed germination, experiments were performed in the weed research laboratory of Ferdowsi University of Mashhad in 2016. The experiments included: Experiment 1: Evaluation of different treatments for breaking Syrian bean-caper seed dormancy: This experiment was performed as a factorial in a completely randomized design with three replications. The first factor is constant germination temperatures at five levels (15, 20, 25, 30, 35 °C) and the second factor is different methods of breaking seed dormancy at 5 levels (without treatment (control), concentrated sulfuric acid (98%) at times 10, 15, 20, 25, 30 and 35 minutes, seed stratification at 5 °C for 7 and 22 days, water soaking the seeds at 25 °C for 7 days and seed scarification using sandpaper for two minutes. Experiment 2: The effect of fluctuating temperatures, light regimes and breaking seed dormancy treatment on Syrian bean-caper seed germination: This experiment was performed as a factorial of three factors in a completely randomized design with three replications. The first factor is alternating temperatures at four levels (10/20, 25/15, 10/30 and 20/30 °C (Day/Night)), the second factor is the light regime at two levels (light and dark treatment (12 hours of light and 12 hours of darkness) and continuous dark and the third factor was the breaking seed dormancy treatment with concentrated sulfuric acid, (the best treatment of the first experiment) at two levels (application and non-application). Experiment 3: Determining the cardinal temperatures of Syrian bean-caper seed germination, this experiment was performed completely randomize design in three replicates. Experimental factors included constant temperatures of 0, 5, 10, 15, 20, 25, 30, 35 and 40 ° C with a light / dark period of 12/12 hours. SAS 9.1 software was used to analysis of variance and compare different treatments. To calculate the germination cardinal temperatures were used, 1. Segmented 2. Dent-like and 3. 4-parameter beta models.

The effect of breaking seed dormancy treatments, temperature and interaction of temperature and breaking seed dormancy treatments on Syrian bean-caper seed germination were significant at 1% level. Maximum germination (96%) was obtained in sulfuric acid treatment for 15 minutes. The results of this study showed that all of treatments have a significant effect (at 1% level) on seed germination rate and total seed germination of Syrian bean-caper. Seed germination of Syrian bean-caper was in the range of 10 to 35 ° C. Seed germination increased with increasing temperature from 10 to 40 °C. Because this plant is native to dryland, it also had significant seed germination at high temperatures. The best temperature for seed germination of this plant was between 20.5 and 25.5 °C. Seed germination stopped at temperatures below 5 °C and at 40 °C. Besides, seed germination was strongly affected by alternating temperatures. Light had not impact on the seed germination of Syrian bean-caper. The highest total seed germination was observed in breaking seed dormancy treatments related to sulfuric acid treatment for 15 minutes at 30 °C and in alternating temperature of 25/15 °C (Day/Night). The four-parameter beta model described the relationship between seed germination rate of Syrian bean-caper and temperature, better than other models. Based on the estimation of this model, the base, optimum and ceiling temperatures for Syrian bean-caper seed germination were 9.83, 16.33 and 39.29 ° C, respectively. Knowledge of these ecological parameters can be useful in quantifying the behavior of weeds in response to various climatic variables, especially temperature. 

The wide range of Syrian bean-caper seed germination from 5 to 35 °C indicates the ability of this weed species to grow in different seasons and in various climatic conditions. Considering the mechanisms affecting the breaking seed dormancy of Syrian bean-caper seeds (remove of seed coat (hardness) and alternating temperatures) as well as the temperature range of seed germination of this plant, it seems that the spread of this plant would be possible in temperate and semi-arid regions. Also, due to the high competitiveness of this species and the ability to produce abundant seeds, this weed might be included in the list of problematic weeds in these areas.

After preparing the spray solution of herbicide, there are situations where the farmer intentionally or unintentionally has to store the prepared spray solution for some time, even several days, in the sprayer tank. For example, when weather conditions for spraying become unfavorable, when a piece of failure in herbicide application equipment occurs, or when the spray solution at night is prepared to use at dawn. Herbicides either decompose chemically or react with compounds in the water, decreasing the efficacy of controlling weeds. Now, the first question that comes to mind is: how long can the herbicide be kept in the sprayer tank without losing its efficacy? In the water, herbicides inhibiting acetyl coenzyme A carboxylase (ACCase) undergo hydrolysis or photolysis, producing metabolites that do not have herbicidal properties. Therefore, the stored spray solution of ACCase-inhibiting herbicides cannot effectively control weeds. For this reason, it is suggested such a spray solution should be thrown away. The metabolites from ACCase-inhibiting herbicides, while not having herbicidal properties, are leached faster in the soil, have a higher half-life, and are more toxic to non-target organisms. Therefore, the suggestion to throw away the stored spray solution of ACCase-inhibiting herbicides does not seem logical not only from the environmental point of view but also from the economic point of view. Now, the second question that comes to mind is: what is the solution to reduce the speed of hydrolysis or photolysis? This study was carried out to investigate (i) the effect of the storage time of the spray solution of three ACCase-inhibiting herbicides (haloxyfop-r-methyl, fluazifop-p-butyl, and sethoxydim) on their efficacy in controlling wild barley (Hordeum spontaneum) and (ii) the effect of two factors of pH and light on the relationship above.

For each herbicide, an experimental three-factorial arrangement (6 × 2 × 9) as a completely randomized design with 4 replications. The first factor was six doses of herbicide (0, 20, 40, 60, 80, and 100% of the labeled dose); the second factor was two pHs of spray water (5 and 8); and the third factor was nine storage time/conditions (0, 24, 48, 96, and 192 h storage in the dark, 12+12, 24+24, 48+48, and 96+96 h storage in the dark+light). The spray solution corresponding to the zero level of the aforementioned third factor was prepared on the same day of spraying. For other levels of this factor, the relevant spray solution with a volume of one liter was prepared in the previous days (24, 48, 96, and 192 h before the day of spraying) and stored in transparent polyethylene terephthalate plastic bottles. The bottles were kept in two outdoor conditions: 1) kept in complete darkness - for this purpose, the bottles were kept in black plastic packed in a carton; and 2) kept in the darkness of the night and the light of the day - for this purpose, the bottles without any cover were exposed to the darkness of the night as well as to the sunlight. The treatments were applied at the four-leaf stage of wild barley; four weeks later, they were harvested, oven-dried, and weighed. A methodology known as dose-response curves was used to analyze the data to obtain the dose required for 50% control (ED50).

When the solution was sprayed immediately after preparation, reducing the pH from 8 to 5 did not significantly affect the ED50 of haloxyfop-r-methyl and fluazifop-p-butyl. While the ED50 of sethoxydim significantly decreased from 136.64 to 113.35 g a.i. ha-1, indicating that pH reduction can improve the efficacy of sethoxydim in the control of wild barely. The possible reason can be related to the difference in the formulation of the above herbicides. Haloxyfop-r-methyl and fluazifop-p-butyl are formulated as pre-herbicide. Under each condition (in terms of pH and light), when the time of storing the spray solution of herbicides was prolonged, a steady reduction of efficacy was observed. In the case of haloxyfop-R-methyl spray solution, when pH was not changed (pH 8), 24 h storage in the dark (43.78 g a.i. ha-1) and 12+12 h storage in the dark+light (41.44 g a.i. ha-1) significantly increased the ED50 as compared to the control treatment (0 h storage (34.60 g a.i. ha-1)). While when pH was reduced (pH 5), the efficacy of five treatments (including: 24 and 48 h storage in the dark and 12+12, 24+24, and 48+48 h storage in the dark+light) did not differ significantly from the efficacy of the control treatment. In the case of fluazifop-p-butyl spray solution, when pH was not changed (pH 8), all storage treatments significantly increased the ED50 as compared to the control treatment (0 h storage (80.64 g a.i. ha-1)). While when pH was reduced (pH 5), the efficacy of two treatments of 24 and 48 h storage in the dark did not differ significantly from the efficacy of the control treatment. In the sethoxydim spray solution, when pH was not changed (pH 8), all storage treatments significantly increased the ED50 as compared to the control treatment (0 h storage (136.64 g a.i. ha-1)). When pH was reduced (pH 5), the efficacy of all storage treatments still did not differ significantly from the efficacy of the control treatment.

If the pH of the spray solution was reduced, the spray solution of haloxyfop-r-methyl can be stored for at least 48 h in each light condition without losing its efficacy. If the pH of the spray solution was reduced and stored in the dark, the spray solution of fluazifop-p-butyl can be stored for 48 h without losing its efficacy. Sethoxydim is very sensitive to the storage of its spray solution. Changing the storage conditions, especially the pH, not only does not help in maintaining the efficacy but also causes a further loss in its efficacy.

Increasing the competitiveness of crops through the use of nitrogen fertilizers and herbicides is an important part of integrated weed management. In recent years, concern over the environmental effects, costs of cultivation, and long-term efficacy of conventional weed management systems have led to increasing number of researchers to seek alternative systems that are less reliant on herbicides and more reliant on ecological processes. This research was conducted with the aim of studying the interaction of different levels of herbicide and nitrogen on weed control and wheat yield improvement.

A field study was conducted at Agronomy Research Farm, Islamic Azad University during 2018-19 with factorial arrangement in a randomized complete block design with four replications. Four herbicide levels (0, 32, 40 and 48 g. metsulfuron-methyl plus sulfosulfuron. ha-1) were applied as early post-emergence application (30 DAS) and five nitrogen levels (0. 60, 120, 180 and 240 kg.ha-1). Hand weeding (control) was applied to compare other treatments.

Results showed that nitrogen × herbicide interaction was significant on grain yield and dry matter of wheat and weed. Grain yield and dry matter of wheat significantly decreased with increasing nitrogen at lower herbicide levels. The effect of herbicide treatment on 1000 grain weight was significant. So that increasing the dose of herbicide up to 48 g.ha-1 increased 1000 grain weight as much as the control treatment. The effect of nitrogen and herbicide on the number of spikes was also significant. By increasing the amount of nitrogen up to 120 kg.ha-1, the number of spike increased. The results showed that the mutual effect of nitrogen and herbicide on grain yield and dry matter of wheat and weed was significant. With the increasing of nitrogen, the grain yield and dry matter of wheat increased in higher herbicide doses and decreased in lower dosed. At low levels of nitrogen, no significant difference was observed between herbicide levels in terms of grain yield and dry matter of weeds, which indicates the higher competitiveness of wheat at low levels of nitrogen and no need to use herbicides. At the same time, at high levels of nitrogen, wheat yield increases at much slower rate than weeds. Therefore, in terms of nitrogen consumption, we will have to use more herbicides in intensive cropping system.
Negative and significant correlation of dry matter of wheat and weeds showed the existence of a close relationship in the interaction of treatments. Therefore, it is possible to use the combination of nitrogen substitutes and herbicides in the integrated management of wheat weeds.

In general, it was observed in this research that with the increase of nitrogen fertilizer, the competitive ability of wheat against weeds decreases, probably due to the higher efficiency of nitrogen consumption in weeds. If weeds are not properly controlled, we will see a significant decrease in wheat grain yield at high nitrogen levels.

Wheat is a crucial crop that plays a significant role in ensuring food security in Iran. Weeds have been one of the major limiting factors for wheat production in Iran and globall. If they are not adequately controlled. Weeds can cause significant damage to wheat crops. Weed damage in wheat fields has been reported to range from 20% to 30% in Iran. The herbicide application is the most important method for weed control of wheat until now. Axial-one@ herbicide, with common names of pinoxaden+ florasulam, has been suggested for weed control of Lollium rigidum, Echinochloa colonum, Alopecurus myosuroides, Phalaris brachystachys, Avena ludoviciana, Stellaria media, Trifolium alexandrinum, Polygonum aviculare, Sinapis arvensis, Ambrosia artemisiifolia, Amaranthus retroflexus, Cirsium arvense. This herbicide has been registered by Syngenta for use in wheat and barley. Pinoxaden (Axial@) belongs to phenylpyrazolines family and inhibitors of the Acetyl-CoA carboxylase (ACC). It has been recorded in the control of narrow-leaved weeds in wheat and barley. Florasulam herbicide belongs to the triazolopyrimidine sulfonamide family and inhibits acetolactate synthase (ALS). Florasolam is the selective herbicide that has been recommended for controlling broadleaf weeds in cereals such as wheat, barley, oats, rye (Secale cereale L.) and triticale (Triticale hexaploid Lart). Also, the Cassic herbicide, which is also known as diflufenican+iodosulfuron-methyl-sodium+florasulam+cloquintocet-mexyl, is a dual-purpose herbicide that has been registered by Syngenta for controlling both broadleaf and narrow-leaved weeds in wheat and barley, oats, rye, and triticale crops. This experiment was conducted to investigate the effectiveness of the herbicides of Cassic and Axial-one in the controlling weeds in wheat fields, determination of the most appropriate dose, comparing their effectiveness with other herbicides commonly used in wheat fields, and evaluating the response of wheat plants to the herbicides.

 An experiment was carried out in weed control in the wheat fields of Karaj, Fars (Darab), Golestan (Gonbad), and Shahrud using a randomized complete block design with 13 treatments and 4 replications during 2020-2021. Experimental treatments included the application of Bromycid AM (bromoxynil + MCPA, 40% EC) + Axial (Pinoxaden, 5% EC) at 1.5 + 1.2 l/ha, Othello (diflufenican+ mesosulfuron methyl+ iodosulfuron methyl sodium, 6%OD) at 1.6 l /ha, Axial One (Pinoxaden+ Flurasulam, 5% EC) at 1.1, 1.3, 1.5, 1.7 l/ha, Cassic (diflufenican+ iodosulfuron-methyl-sodium+ florasulam+ cloquintocet mexyl, 47% WG) at 170, 200 and 230 g/ha with and without cytogit, and control (weed free). Herbicide treatments were applied during the tillering stage (Zadok’s Stage 25(. The plot had dimensions of 8 x 2 m with a plant density of 400 plants m-2. Each plot consisted of 8 planting lines with a row spacing of 15 cm. The distance between the plots was one meter, and there was a two-meter gap between replications. To increase the accuracy of the experiment, each test plot was divided into two equal sections, with the upper half serving as the control without spraying and the lower half being sprayed. The spraying was done using a fixed-pressure back sprayer equipped with a fan spray nozzle (8002) at a pressure of 2 bar and spray volume of 300 L ha-1. Traits such as weed density, weed biomass, and grain yield were recorded. Weed numbers and dry weights were determined by randomly selecting 0.50-m2 quadrats per plot, while grain yield was recorded for 3 m2 in each plot. The data were checked for normality and analyzed using SAS 9.3 software through analysis of variance. The means were separated using the Duncan test at the 5% level of significance. 

 The results of experiment indicated that the herbicide treatments led to a significant decrease in the density and dry weight of weeds, as well as a significant increase in grain yield. The Axial One@ at rate 1.7 L ha-1 was found to be more effective in controlling Avena ludoviciana, reducing its density by 95%, compared to On the other hand, Cassic herbicide at a rate of 230 g per hectare was more effective in controlling Lolium rigidum, reducing its density by 95%, compared to Axial One@ herbicide. Both herbicides, however, led to a significant reduction in the dry weight of Descurania sophia, Polygonum avicular, Sonchus oleracea, Veronica persica and Sinapis arvensis from 85 to 95%. No visual injury symptoms were observed on wheat after the application of these herbicides. Grain yield increased with the application of Axial One (at rate of 1.5 to 1.7 L ha-1) by 5 to 24%, and Cassic (at rates of 200-230 g ha-1 + cytogit) by 8 to 28%. These findings were consistent with the results of previous studies (Minbashi et al., 2020). The application of Oxial herbicide increased grain weight of wheat (Azhar et al., 2013).

 Based on the results of these experiments, it can be concluded that Axial One@ and Cassic@ herbicides showed the best control on A. ludoviciana and L. rigidum respectively, and also led to a significant increase in grain yield compared to half of the control plot. Therefore, the Axial One@ (1.7 L ha-1) and Cassic@ (200-230 g ha-1 + cytogit) can be considered as good to excellent options for weed control in wheat fields. It is recommended to use these herbicides for weed control in wheat fields.