فصلنامه مطالعات حفاظت گیاهان
سال سی و هشتم شماره 4 (زمستان 1403)

Psylla is a key pest in important pear Pyrus Communis -growing areas in Iran. Detection of population fluctuations in ecological models can be traced with time series data. Population dynamics is the result of changes in the population size that ascend from the random and independent contribution of births, deaths, and migrations of population individual members. Population dynamics can be simulated by considering the role of each individual in a time unit as an independent and separate random variable. Mathematical models of resource-consumer relationships can understand miscellaneous patterns of population dynamics, leading to a set of population behavioral patterns under the influence of food resources. This research was conducted on the population dynamics of eggs, nymphs, and adults of pear psylla Cacopsylla pyri L. under feeding conditions from nine pear cultivars in field conditions. Psylla is a key pest of pears and is distributed worldwide. In the climatic conditions of regions like Iran, where spring and summer are dry and rainfall is less, the indirect damage of honeydew secretions is more than the damage from sucking plant sap.

The time series of the population of each growth stage of pear Psylla is a group of observations obtained by regular variable sampling of the eggs, nymphs, and adult Psylla population in a period of four years (2020-2023). The integrated autocorrelated moving average (ARIMA) model was used to forecast the future pear psylla population on nine pear cultivars. ARIMA model suitability criteria and information criterion Bayesian normalized (BIC) were calculated. The plots of residual autocorrelations and partial autocorrelations that show the degree of correlation of the residuals of the model in the actual forecast were premeditated. A cross-correlation model was used to replicate the population model of each developmental stage against the population route of another developmental stage.

The fitted models were significant at the 0.01% level for the populations of pear Psylla on nine cultivars. The ARIMA time series model showed good capacity in forecasting the population of egg, nymph and Adult. Differences among the fit indices of the model were observed in all three developmental stages. The mobility of the growth stage has been one of the most important reasons for these differences. Because with the increase in mobility, the accuracy of sampling usually decreases and population sampling becomes more difficult. The type of host cultivat has also been effective in determining the predictive power of the model. The values of residual autocorrelations and partial autocorrelations in most growth stages and different pear cultivars were smaller than 0.5 in absolute terms, and this indicates that the remaining effective data was not included in the fitting of the time series model in the minimum amount. A sinusoidal trend occurs in the curve of pears Psylla population density fluctuations. The trend of changes in observations was the same as predicted by the model. In some stages such as adult and in cultivars such as Shah Miveh where the population densities were higher than normal, the sinusoidal trend was not observed in the population forecast by the model. The relationship between the population of alternating developmental stages has been direct and increasing and inverse and decreasing at different periods of seasons. These changes were caused by the difference in the pear cultivars quality for pear psylla growth stages. The average absolute value of the cross-correlation varied between 0.3 and 0.4, which indicates the average detection power of each developmental stage compared to the subsequent developmental stage. The maximum detection power in different cultivars was related to the transition of the population from the nymph stage to the adult. In pear cultivars with higher population density, which most of the times had a population above the normal limit, such as Shah Miveh and Dargezi cultivars, the model recognized ability was less, and instead, in cultivars with subnormal population density, such as Boheme and Harvest Queen, the model recognize ability was lower. In cultivars that have less population carrying capacity, births, and mortality reach the equilibrium point earlier than other cultivars. In natural environments, the measurement of living spaces has different dimensions, including nutrition quality.

The flexibility of the models in describing the different annual phenological behaviors of the various growth stages of the pear psylla and the possibility of self-calibrating the models with the help of autocorrelation and cross-correlation models make this approach a valuable tool for monitoring the population of this insect.

Acyrthosiphon pisum Harris aphid is one of the most important aphid species in alfalfa fields. In the case of a large population, it directly and indirectly damages the host plants. Reports have shown their presence in several regions worldwide, including Iran, particularly on fodder plants and most plants belonging to the legume family. Geostatistical analysis provides an alternative approach for the characterization of spatially variable ecological data, particularly for insect population. Geostatistics includes two parts, variography and kriging. The foundation of geostatistics is semi-variogram, which is a variance diagram based on the distance between samples, which shows the structure of spatial relationship among the samples. Kriging is one of the geostatistical methods that are used to estimate the regional variable value in different areas of the farm. Regarding geostatistical estimation, the value of a quantity in areas with known coordinates is estimated by using the same quantity in other points with known coordinates. This method allows for precise estimation of the value of a local variable in areas where sampling has not been conducted. These maps can accurately predict population changes and the likelihood of reaching the economic threshold in various parts of the farm. As a result, they can be highly effective in pest management programs.

This research was carried out in the crop year of 2021-2022 in two three-year alfalfa fields located in two cities of Dezful (Khuzestan) of Baghdadi variety and Borujard (Lorestan) of Hamadani variety, with an area of ​​five and seven hectares, respectively. To record the population density of desired pest in different parts of the selected farms, the number and location of each sampling station were determined based on their length and width coordinates (in meters) were considered constant during the sampling period. To determine the location of sampling stations, first, four main directions were identified in the fields and from the southwest area of ​​the fields, and to eliminate the marginal effects of the fields, a point with coordinates (0,0) was selected two or three meters from the edge of fields. Each of desired fields was divided into regular grids of 25 x 25 meters. The farms in the Dezful and Borujerd areas were examined, and a total of 90 and 130 sampling sites were identified and labeled with plates. The parameters of each station were recorded on these plates. The sampling started in March 2022 and lasted until mid-November 2022. To sample the population of aphids, a 1 x 1m quadrat was used in such a way that two quadrats were randomly thrown in each grid and six stems were selected from each box, and a total of 12 stems were selected and shaken inside a pan, and counted the aphids. A total of 22 sampling stages were performed. Excel 2010, SPSS ver. 26 and GS+ version 5.1 software were used for data analysis. The data related to each station were checked for normality by helping Kolmogorov-Smirnov test, and if necessary, they were placed in the determined coordinates by helping one of the appropriate data conversion methods. Then, variogram curves, as well as kriging maps for each sampling date were presented in the data that had the highest R2 and degree of spatial dependence.

The results of surveying the geostatistical characteristics of A.pisum aphid in an alfalfa field in Borujerd city showed that out of 22 sampling cases, 12 cases were fitted with spherical model, eight cases with exponential model, and two cases with linear model (without spatial structure), which in all cases which were fitted with two spherical and exponential models, spatial dependence was observed. In these two models, the ratio of the nugget to the sill was very low, which resulted in an increase in the percentage of spatial dependence. The degree of spatial dependence varied between 0.500 and 0.999. The effective range in the spherical model was between 121.9 and 221.2 meters. In each of the variograms, except for three datasets, in the remaining datasets, the R2 was high and between 0.55 and 0.95. Its distribution pattern was aggregative. Regarding this aphid species, in alfalfa fields of Dezful city, out of 21 sampling cases, 12 cases were fitted with spherical model, eight cases with exponential model and one case with the linear model. The spatial dependency in the two models ranged from 0.500 to 0.986, indicating a correlation between the distributions of aphids. Furthermore, the population distribution of this aphid species was shown to be aggregated. The effective range for them in the spherical model was between 137.9 and 493.4 meters. The percentage of the degree of spatial dependence for both farms was estimated to be more than 0.5, which means that more than 50% of variability among the data can be described by the spatial dependence, as a result of which the high degree of spatial dependence increases the accuracy of statistical estimation. By kriging maps, the density points of aphids population were checked on different dates, which can be used for advance warning at the beginning of the damaging stages, and by spraying about one-fifth of the field, a high percentage of the pest population can be reduced and avoid unnecessary spraying.

Finally, better outcomes in terms of the environment and the control of the targeted pest may be achieved with less pesticide use by applying the science of geostatistics and creating kriging maps. To accomplish this significant objective, using targeted pest site control is a good option. Moreover, preparing spatial distribution patterns of insects and the preparation of distribution maps (kriging) make it easier to achieve this goal.

Cabbage aphid Brevicoryne brassicae (L.) (Aphididae: Hemiptera) is one of the important pests of cruciferous plants, which causes a lot of damage to plants of this family by feeding on plant sap and transmitting disease. The use of plant derived chemicals such as Diabon and Persian lilac (Melia azedarach L.) extract as an alternative to synthetic insecticides in the integrated management of this pest has been studied and considered. On the other hand, the use of synthetic insecticides in order to control sucking pests is common, and the high percentage of mortalities by acetamiprid and clothianidin against sucking pests was investigated and it was proved that the insecticidal properties of these pesticides are based on the systemic property of them. Potassium element is also important because it plays an important role in the general balance of phosphorus and nitrogen inside the plant, and if potassium is at the level required by the plant, it has an inhibitory effect on the growth and reproduction of insects. In this research, the effect of mineral compounds, plant derived chemicals and synthetic insecticides on the cabbage aphid population was investigated in the conditions of the open space of the urban landscape.

This research was carried out in the green space of Zarand city, Kerman province on ready-to-plant ornamental cabbages that are contaminated with cabbage aphids. For each experimental treatment, sixteen infected cabbage plants with aphids were randomly planted in plots with an area of one square meter (1×1) at a distance of 20 cm from each other. In order to evaluate the effect of mineral, plant and chemical compounds to control the population of cabbage aphid on ornamental cabbage, experiments were carried out in the form of 9 treatments as follows: (P-N): Potassium nitrate at a concentration of 3000 (ppm) - (P-S): Potassium sulfate at a concentration of 2000 (ppm) - (P-Si): Potassium silicate at a concentration of 2000 (ppm) - (MI): Water-ethanol extract of Melia azedarach (fruit) at a concentration of 3000 (ppm) - (CT): commercial form of a concentrated suspension (SC-20) of clothianidin at a recommended rate of 500 (ppm) - (AT): commercial form of water-soluble powder (SP-20) acetamiprid at a recommended concentration of 500 (ppm) - (AM): commercial form of emulsion concentration (EC-1.8) abamectin at a recommended rate of 500 (ppm) - (DB): Diabon 10% to the recommended concentration of 8000 (ppm) - (C): water as control. The foliar spraying with each of the treatments was carried out in one turn by a 20-liter backpack sprayer with a certain volume on the ornamental cabbages of each treatment. Sampling of the aphid population was done on three occasions at 7, 14 and 21 days after foliar spraying at 8 am. The population of aphids on the leaf was counted by a stereomicroscope and in the area of the template of 1.5×1.5 cm, which was placed on a specific area of the leaf. In this study, the population of living aphids, including: nymphs, wingless and winged insects, were counted and used for statistical analysis.

In the first record, the population of nymphs, wingless and total insect in MI, CT, AT, AM and DB treatments have significant differences with the control treatment. But the treatments containing potassium element (P-N, P-S and P-Si) have no significant difference with the control treatment. Comparison of the results 14 days after foliar spraying showed that AT and CT treatments have a significant difference with the control treatment in the stages of nymph, wingless and the total population. Also, in the other research, it was found that fourteen days after the use of acetamiprid, this insecticide was still successfsul in controlling the rose aphid population, which is also consistent with the results of this experiment. Fourteen days after foliar spraying, the treatments that contain potassium element have reduced the population compared to the control only at the stage of wingless insects. Past research showed that potassium element is effective in the reproduction of this aphid. In other biological stages in three recording times, the population density of the treatments that had mineral compounds are not significantly different from the control treatment. This suggests that these compounds may not have an effect on the control of cabbage aphid. Investigations showed that twenty-one days after foliar spraying, in the nymph stage, P-N, CT, AT and AM treatments have significant differences with the control treatment. Other treatments have no significant differences with the control treatment. In the stage of wingless insects, it was found that there is a significant difference between the CT, AT and AM treatments with the control treatment, while the other treatments do not have a significant difference with the control treatment. In the total population of aphids twenty one days after treatment, it was found that CT, AT and AM treatments have significant differences with the control treatment.

Based on the results of the present research, acetamiprid and clothianidin have more effects in controlling the population of this aphid than other insecticides. But in the third record, in clothianidin treatment, the beauty of the appearance of ornamental cabbages was reduced. Therefore, it is suggested to test lower concentrations of this insecticide in the next research. The short-term effect of M. azedarach extract on the population of this aphid may be related to insufficient persistence, low concentration or slow penetration of this extract in the plant tissue. But due to the importance of this botanical compound, it is suggested to conduct new research in relation to increasing the effect of this compound by increasing the concentration, changing the formulation and increasing the number of times of foliar spraying. Mineral compounds containing potassium element did not have much effect in controlling the population of this aphid, which can be related to the activity of cabbage aphid under the leaves. It is obvious that the lack of contact of recent mineral compounds with aphids is effective in the failure of these compounds.

Crown gall is an economically important plant disease that affects dicotyledonous and a few monocotyledonous plants in orchards, farms, and nurseries, worldwide. The disease is caused by Agrobacterium tumefaciens (Smith & Townsend, 1907) Conn 1942, a Gram-negative bacterium from the family of Rhizobiaceae in the class of AlphProteobacteria. This bacterium can survive in the soil as well as within host plants. The key characteristic of this bacterium is its ability to transform regular plant cells into tumor cells. Once this transformation is complete, the cells can continue to grow and divide independently of the bacterium. Molecular methods play a key role in the identification, classification and taxonomy of prokaryotes. Housekeeping genes are highly conserved protein-coding genes used to distinguish between different taxa of bacteria. In this study, the recA gene sequence was used to evaluate the efficiency of this gene in identifying and determining the phylogenetic relationships of tumor-forming Agrobacterium tumefaciens and Agrobacterium rubi (Hildebrand, 1940) Starr & Weiss, 1943 isolates.

The pathogenic isolates were isolated from tumors on the branches of cherry, plum, and apple trees in the orchards of Urmia, Naqadeh, Sardasht, and Khoy; located in West Azerbaijan province of Iran. In a previous study, phenotypic identification of the isolates was done, as well as the pathogenicity test with the gall formation on tomato crown. In this study, the recA gene sequence of four isolates (AT-U2, AT-K2, AT-N25 and AT-N15) was used for drawing the phylogenetic tree. After DNA extraction, polymerase chain reaction (PCR) was done using 91F/595R primers. Each PCR reaction was performed in a 25 µL PCR cocktail containing 12 µL of Taq DNA Polymerase 2x Master Mix RED (Amplicon, Denmark), 1 µL of each primer (10 pmol µL-1), and 1 µL of template DNA (50 ng). The PCR amplification program was carried out under the following conditions; initial denaturation cycle at 94 °C (5 min), 35 cycles of denaturation at 94 °C (50 sec), annealing at 57 °C (50 sec) and extension at 72 °C (1.5 min), and a final extension at 72 °C for 10 min. The sequences of the studied isolates were compared with the sequences of the reference strains registered in the NCBI database. Sequence of the recA gene of A. tumefaciens and A. rubi strains, as well as strain AOL15 of Agrobacterium albertimagni Salmassi et al., 2002, as an outgroup strain, was obtained from GenBank. Phylogenetic relationships were inferred, by applying the Kimura-2-parameter model. The neighbor-joining (NJ) method and the adjacent method by MEGA 11 software were used for the phylogenetic tree and tested by bootstrap analysis with 1000 repetitions.

A 462 bp fragment was amplified in all bacterial isolates. Comparison of the recA sequence showed similarity of 99.95%-100%, with the reference strains of A. tumefaciens in GenBank. In the phylogenetic tree, sequence of the recA gene of studied isolates and reference strains of A. tumefaciens and A. rubi obtained from GenBank were used. The phylogeny tree included two main clads. The first clade included two subclades. AT-U2 placed in the first subclade and AT-K2, AT-N25 and AT-N15 placed in the second one. All the reference strains of A. tumefaciens from different countries were placed in the first clade, as well. In the second clade, A. rubi was placed separately from A. tumefaciens isolates. Currently, the analysis of housekeeping genes sequences is widely used to achieve higher accuracy in the phylogenetic relationships of different bacterial taxa. Among the bacterial conserved genes, sequence of the recA gene has been the interest of bacteriologist scientists (Costechareyre et al., 2010). Tumor-forming bacteria isolated from grapevine (Vitis vinifera L.), rose (Rosa sp.), red raspberry (Rubus idaeus L.), and cornelian cherry (Cornus mas L.) were classified in the Agrobacterium genus based on the 16S rRNA gene, but the result of phylogenetic analysis based on atpD, recA, and rpoB showed that some of the studied strains classified in Agrobacterium rosae Kuzmanovic et al., 2018, which is close to the species A. rubi and Agrobacterium skierniewicense (Puławska et al., 2012) Mousavi et al., 2015 (Kuzmanovic et al., 2018). A study of the recA gene sequence in 138 strains from 13 Agrobacterium species and genomospecies led to the differentiation between A. tumefaciens, Agrobacterium vitis Ophel & Kerr, 1990, A. rubi and Agrobacterium larrymoorei Bouzar & Jones, 2001 species (Costechareyre et al., 2010). In a multilocus sequencing study using rpoB, recA, gyrB, and atpD sequences, Agrobacterium isolates from various plants identified as A. larrymoorei and A. rubi (Mafakheri et al., 2019). The study of housekeeping genes has been proposed not only as a phylogenetic tool to clarify the relationships between prokaryote taxa but also as an alternative to previous methods, such as DNA-DNA hybridization and ITS sequence (Costechareyre et al., 2010). According to our results, A. tumefaciens strains were situated in a separated clade from A. rubi and A. albertimagni strains. Therefore, the recA gene sequence is a suitable tool to identify A. tumefaciens from other Agrobacterium isolates.

Results of the phylogenetic analysis revealed that using the recA gene sequence has enough efficiency in differentiating A. tumefaciens from A. rubi strains. This finding suggests that employing the sequences of the recA gene in phylogenetic relationship studies of Agrobacterium species provides accurate results in bacterial taxonomy.

Grapevines, as a vital agricultural product, face significant challenges from pests and diseases that adversely affect both the quality and quantity of the crop. Among these, viruses are particularly detrimental, with 86 different species identified in grapevines. The viruses associated with grapevine leafroll disease (GLD) are considered the most prevalent in vineyards. Specifically, six species of grapevine leafroll-associated viruses (GLRaVs), belonging to the family Closteroviridae, are linked to this disease. These viruses typically enter vineyards through infected cuttings and are disseminated by vectors, notably mealybugs. The symptoms of GLD manifest as downward rolling of leaf margins, leaf interveinal reddening, and leaf interveinal chlorosis across various grapevine varieties. These symptoms negatively impact the quality of the berries, ultimately affecting yield and marketability. The GLRaV-1 genome is composed of positive-strand RNA and contains ten open reading frames (ORFs), which play crucial roles in its biology and pathogenicity. In Iran, GLRaV-1 has been identified as one of the most widespread grapevine viruses, exhibiting high genetic diversity that complicates management and control efforts. This study focuses on the identification of GLRaV-1 and the phylogenetic analysis of its isolates in the vineyards of Razavi Khorasan province. By understanding the genetic relationships and variability of GLRaV-1 isolates, this research aims to provide insights which could be useful for designing effective management strategies and improving the overall health of grapevine in the region.

In the spring of 2020, a study was conducted in the Kashmar region of Khorasan Razavi province, focusing on grapevine plants exhibiting distinct symptoms of viral infection. A total of 70 samples were collected from affected plants. The RNA was extracted from these samples to facilitate the detection of grapevine leafroll-associated virus 1 (GLRaV-1). The initial identification process involved reverse transcription-polymerase chain reaction (RT-PCR). This method confirmed the presence of GLRaV-1 in 22 samples, marking a crucial step in understanding the viral infection's prevalence. To ensure the accuracy of the RT-PCR results, Sanger sequencing was used on the amplified fragments from three selected samples. This technique provided definitive confirmation of the viral identity by analyzing the nucleotide sequences, thereby validating the initial findings from the RT-PCR. Data analysis included several critical components. Nucleotide sequence similarity analysis was performed to compare the identified GLRaV-1 isolates against known sequences in databases, assessing their similarity and identifying potential genetic variants. Following this, multiple sequence alignments were conducted using MAFFT software, arranging the sequences to highlight similarities and differences among the isolates. The phylogenetic tree was constructed using the Maximum-Likelihood method with MEGA7 software.

The samples collected from black grape vineyards in Kashmar exhibited mild yellowing and downward rolling of leaf margins, symptoms commonly associated with increased anthocyanin levels in red grape varieties. In samples infected with GLRaV-1, a fragment of the minor capsid protein 2 (Cpm2) gene was successfully amplified, while no such fragments were detected in healthy plants. This indicates the presence of GLRaV-1, a virus recognized as one of the common pathogens affecting grapes across various regions of Iran. The GLRaV-1 is primarily transmitted through vectors or contaminated cuttings, which emphasizes the importance of monitoring and controlling these pathways to prevent outbreaks. Sequence comparisons revealed that nucleotide identity among Iranian isolates ranged from 84.2% to 100%, while identity with GenBank isolates varied between 77.6% and 87.7%. This high level of genetic diversity among the isolates may enhance the virus's adaptability to different grape varieties, posing challenges for management and control. The observed diversity at the genomic level was consistent with previously reported data regarding the sequence divergence between the two GLRaV-1 groups (Alabi et al., 2011; Sabella et al., 2018; Fan et al., 2015). Phylogenetic analysis further demonstrated that Iranian isolates of GLRaV-1 clustered into two main groups, indicating that the phylogenetic relationships are not strictly related to geographical origin. In previous studies, global isolates of GLRaV-1 have also been distinguished into two different groups based on the gene encoding the minor coat protein 2 (Alabi et al., 2011; Elci, 2019). This finding suggests that the spread of the virus may occur independently of the location, highlighting the need for comprehensive management strategies. To mitigate the spread of GLRaV-1, the use of virus-free plant materials is essential (Alabi et al., 2011; Bruisson et al., 2017). The genetic diversity of GLRaV-1 significantly influences the epidemiology of grapevine leafroll disease, underscoring the importance of producing virus-free plants. Continued research is crucial to understand the underlying causes and effects of this virus. Additionally, developing more sensitive and specific diagnostic tests, along with new control strategies, is vital for effectively managing GLRaV-1 and safeguarding grapevine health.

Among oilseeds, canola is one of the most important oilseed plants in the world. Weeds are a very important competitor and one of the main factors reducing production in canola cultivation. Early control of weeds with pre-emergence herbicides reduces weed damage in canola. A herbicide acts selectively and controls weeds without harming the crop, if applied correctly and at the right time, otherwise, it will not only fail to control the weeds but also reduce the crop yield. Every weed is sensitive herbicides use during a specific growth stage, and if the recommended time for the use of herbicides is not observed, it will cause damage to the yield of the crop. To prevent increasing weed resistance to post-emergence herbicides and diversify timing and mode of action for herbicides, this experiment aimed to investigate the effectiveness of imazathapyr, trifluralin and oxyfluorfen herbicides on rapeseed (Brassica napus L.) weed control.

In order to investigate pre-emergence herbicides and application time on weed control and canola yield, a research was conducted in the agricultural year 1402-1401 in the research farm of the Department of Production Engineering and Plant Genetics, Faculty of Agriculture, Shahid Chamran University of Ahvaz. The experiment was conducted in a factorial experiment based on a randomized complete block design with three replications. The experimental factors were the type of pre-emergence herbicide at three levels (imazethapyr, trifluralin, oxyfluorfen) and the time of herbicide application at four levels (two weeks before planting, one week before planting, at planting, and one week after planting) along with an unweeded control. The Hyola 50 canola variety was planted on the first of Aban (October 23). The number and dry weight of weeds per square meter were measured by identifying the species and separating broad-leaved and narrow-leaved weeds at five times including 30, 60, 80, 100 days after planting and harvesting time. After ripening of rapeseed plants, seed and biological yield were measured. To estimate the yield components, including the number of plants per square meter, the number of branches and siliques per plant, and the number of seeds per silique, 10 plants were randomly selected from the middle lines of each plot by removing the marginal effects. The data were checked for normality and analyzed using SAS 9.4 software through analysis of variance. The means were separated using the Duncan test at the 5% level of significance.

The results showed that seed yield of canola, under the application of trifluralin herbicide (on average of all four spraying times) and oxyfluorfen herbicide two weeks before planting, increased by 18% and 12%, respectively, compared to the unweeded control. There was a positive correlation between seed yield with the number of plants per square meter at harvest time (90%) and a negative correlation with the number and weight of weeds (between -34 and -39%). The yield components, the number of plants per square meter, the number of branches and siliques per plant, and the number of seeds per silique were also affected by the interaction of the type of herbicide × time of spraying. Among the yield components, there was no significant difference in the thousand-grain weight of canola between the levels of herbicide type, spraying time, and their interaction. The results showed that canola was very susceptible to imazethapyr herbicide at all four application times. Compared to the other two herbicides, imazethapyr caused the highest percentage of canola burn and the lowest number of plants per square meter at harvest time. Imazethapyr also resulted in the lowest seed yield and other yield components. There was no damage to canola plants in the trifluralin herbicide treatment at all four application times and the yield components were superior until harvest. All three herbicides significantly reduced the population of broadleaf and narrowleaf weeds in the canola field compared to the unweeded control at 30 and 60 days after planting. The reduction in the population of broadleaf and narrowleaf weeds continued from 80 days after planting until harvest in trifluralin and oxyfluorfen herbicides, although this effect of reducing the weed population was more pronounced in trifluralin herbicide than in oxyfluorfen herbicide. At the end of the season, the population of both narrow-leaved and broad-leaved weeds increased in plots of rapeseed that had been damaged by the application of the herbicide imazethapyr. This was due to the decrease in interspecific competition.

It seems that for early weed control, when rapeseed is growing slowly in the low temperatures of autumn, in addition to the herbicide trifluralin, oxyfluorfen, as a pre-emergence herbicide, can be a good option for further research to introduce it in rapeseed, especially in fields with dominant broad-leaved weeds.

Wheat (Triticum aestivum L.) is one of the most important cereal crops in the world as a source of carbohydrates, protein, and minerals (Esposito et al., 2023). Its yield and planted area account for about one-third of food production. Thus, wheat plays a significant role in global food security. Various factors such as climate change, food shortages, and weeds are the most significant challenges for wheat production and seriously limit continuous improvements in wheat yield and grain quality. Vetch species are among the most important weeds in wheat fields. Since knowledge and awareness of weed phenological stages play an important role in weed management, the present study was conducted to investigate the comparative phenology of caspian vetch (Vicia hyrcanica) and narbon vetch (Vicia narbonensis) as two problematic weeds with wheat.

 The experiment was conducted in the 2022-2023 agricultural year on an irrigated farm with a sprinkler system in the village of Chaqazard, 24 km from Kermanshah, in the Mahidasht district (46°48' E, 34°17' N, altitude 1362 m) at Kermanshah province. The area has a temperate to cold, dry climate with hot, semi-arid summers and cold, wet winters. The average rainfall during the experiment was 347 mm. The experimental factors include the date of vetch planting (once every three weeks after wheat cultivation), the scratching of vetch seeds (scratching and non-scratching), and the presence and absence of wheat cultivars. A separate experiment was designed using the above three factors for vetch species. For this research, irrigated Pishtaz wheat seeds were purchased under Kermanshah Agricultural Jihad supervision, and narbon vetch and caspian vetch seeds, considered weeds, were collected from the region. A factorial experiment was conducted in a randomized complete block design with four replications, including vetch planting dates (every three weeks in autumn, every five weeks in winter), seed scratching (scratched, non-scratched), and the presence or absence of wheat. A weed-free plot of wheat was included. The land was prepared on November 6, and wheat was planted on November 15 with 20 cm row spacing. narbon vetch and caspian vetch were planted between the wheat rows on November 15, December 5, January 25, and February 27, with irrigation starting November 16. Growth stage development of the vetch was monitored twice weekly, focusing on germination, cotyledon emergence, branch production, flowering, and pod formation.

The results of this study showed that on the first planting date (late November), the highest vegetative and reproductive growth of narbon vetch and caspian vetch was observed, and the lowest amount was obtained on the fourth planting date (mid-March). On the other hand, it was found that scraping had a different effect on the characteristics of narbon vetch and caspian vetch and increased some of the traits of these two weed species. In addition, the most significant increase in the growth and seed production of narbon vetch and caspian vetch was seen in their pure planting, and by planting these weeds between the rows of wheat, their amount decreased. Based on the results of the phenology stages in narbon vetch, the GDD and the number of days required to complete the emergence stage in different planting dates varied between 35.9 to 164.65 and 19 to 75, respectively. In caspian vetch, the GDD of growth and the number of days required for the emergence stage in different planting dates varied between 24.1 to 68.8 and 9 to 83 days, respectively. The results of comparative phenology stages showed that the life cycle of narbon vetch and caspian vetch was 16 days earlier than wheat, and their ripening did not coincide with wheat ripening.

The study results indicated that delaying the emergence of vicia (especially on March 9) benefits the crop. Specifically, the later establishment of narbotn vicia and caspian vetch on March 9 reduced their competition and seed production compared to other emergence dates. Thus, delaying the emergence of these weeds can mitigate their impact on fields. Conversely, narbotn vicia and caspian vetch seeds exhibited dormancy, and scarification broke dormancy, leading to quicker weed emergence and crop damage. The emergence of these weeds between wheat rows also showed a negative impact due to better resource use and intense interspecies competition for light and space. Phenological stage analysis revealed that except for the maturation stage, other growth stages of these weeds matched those of wheat. The Vicia life cycle was 16 days shorter than wheat's, with their maturation not coinciding. The optimal herbicide application time for these weeds is at wheat’s 3-6 leaf stage for the first and second emergence dates and from tillering to the first detectable node for the third and fourth emergence dates.