فصلنامه مطالعات حفاظت گیاهان
سال سی و پنجم شماره 3 (پاییز 1400)

The root-knot nematodes of the genus Meloidogyne are highly adapted, obligate plant parasites, consisting of nearly one hundred valid species, and are considered the most economically important group of plant-parasitic nematodes. The control of root- knot nematodes has been sought by the use of nematicides, resistant varieties, crop protection and organic amendments. Because of toxicity of nematicides for environment, human health and wild life, application of them are restricted. Identification of genes responsible for resistance to root-knot nematode and their mode of actions have attracted a lot of attentions to develop resistant cultivars. Resistance in the plant species is often due to the presence of specific genes. In resistant cultivars, resistance genes can prevent or suppress one or more stages of nematode infection cycle. In fact, in response to nematode infection, resistance genes can prevent or suppress one or more stages of nematode infection process. In the most incompatible interactions, depending on the mechanism of resistance, the root galls are reduced or eliminated at the sites of infection. Assessment of resistance to the root-knot nematodes in different tomato cultivars is helpful for selection of suitable cultivars with satisfying plant growth and nematode tolerance traits for suitable management of the root-knot nematode. Thus, in the present study we evaluate the response of some tomato cultivars for resistance to root-knot nematodes, Meloidogyne javanica, in greenhouse conditions.

In this study, the nematode population was obtained from roots of tomatoes collected at a glasshouse in Tirtash–Mazandaran, Iran.The root-knot nematode were purified and multiplied on tomato cv. Early Urbana plants. Then the nematode species were identified based on morphological and molecular methods. The seeds of ALYSTE F-1, ARYZA F-1, Rutgers, Early Urbana, Dutch Mobil and Hungarian Mobil tomato cultivars were spawned in equal proportions of cocopit, perlite and vermiculite and irrigated for 3 weeks. Then, the seedlings were transferred to the pots containing mixture of sterile soil, sand and vermiculite (1:1:1) with 9 cm diameter. After 2 weeks, the seedlings were inoculated with 3000 second stage juveniles (J2s) of M. javanica. The pots were kept for 70 days at 24-33°C and 50% relative humidity. Resistance evaluation was based on plant growth and nematode reproduction indices. Growth indices were fresh and dry weight of root and aerial part, root length, plant height and total fresh and dry weight and nematode reproductive indices were number of galls and egg masses/g root and total root, eggs/egg mass, eggs/root, J2s /soil, final nematode population and reproduction factor (RF) were measured and recorded. The experiment was carried out in a completely randomized design with 5 replicates in the both of inoculated and non-inoculated with nematode. Data were analyzed in Minitab version 17. The means were compared by using Fisher,s LSD. Also to determine the resistance level, resistance index (RI) and reproduction factor (RF) were calculated. The RI is depended to frequency of the gall and egg mass index in the root. To determine Gall Index (GI) and Egg mass Index (EI), 0= no galls or egg masses, 1= 1 to 2, 2= 3 to 10, 3= 11 to 30, 4= 31 to 100 and 5= more than 100 were considered, in the following for RI, 0-0.9= immune, 1-1.9= highly resistant, 2-2.0= resistant, 3-3.9= moderately resistant, 4-4.9= intermediate, 5-5.9= moderately susceptible, 6-6.9= susceptible and more than 7= highly susceptible. The reproductive factor (RF) of the root-knot nematode in the different genotypes was obtained by dividing the final and initial population densities of the nematode (RF = Pf/Pi).Thus, RF≤1, GI≤2 = resistant; RF≤1, GI>2= moderately resistant; RF>1, GI≤2= tolerant and RF>1, GI>2 susceptible.

This study results showed that ALYSTE F-1, had the lowest number of gall, egg mass, second stage juveniles and consequently the lowest nematode population and was recognized as moderately resistant cultivar. In terms of the growth indices, ALYSTE F-1 also had the highest growth characteristics and contained a significant difference with other cultivars. Totally, Rutgers, ARYZA F-1, Dutch Mobil, Hungarian Mobil and Early Urbana varieties were introduced as highly susceptible cultivars based on RF and GI. However, Dutch Mobil, Hungarian Mobil and Early Urbana had the highest nematode population and reproduction factor (RF). In terms of the growth traits, the results showed that Rutgers, as a highly susceptible cultivar, was more impressible than other cultivars followed by Dutch Mobil. The cluster analysis based on the sum of the plant growth and nematode reproductive traits showed that ALYSTE F-1 cultivar was distinct from the other cultivars. Thus, the cluster analysis confirmed the results of comparison of the average of the plant growth and nematode reproductive traits.

Based on the results of this study, ALYSTE F-1 was identified as a moderately resistant cultivar to the root- knot nematode, M. javanica. and the others were highly sensitive to the nematode.

Fusarium wilt of tomato is one of the most important and common tomato diseases growing in the cultivated areas of this plant around the world. Biological control of plant diseases using non-pathogenic microorganisms has attracted the attention of many researchers. Trichoderma is one of the most successful and widely used microorganisms that prevent fungal damage in plants. Trichoderma spp. have different mechanisms to deal with plant pathogens, such as increasing plant resistance and activating defense reactions, direct confrontation with the pathogen through mycoparasitism, antibiosis, competition, plant growth stimulation, regulation and induction of plant growth factors including auxins, cytokinins and ethylene that stimulate growth Plants are involved. Totally, they destroyed biological reproductive organs, survival and reproduction, weakening and expelling pathogens from plant debris and preventing the formation of contaminants are the three basic methods by which biological control is achieved. Trichoderma is one of the living fungi that can perform the above three mechanisms simultaneously and as a result it is used as a biological fungus that increases plant growth and activity of beneficial microorganisms.

In this study, the effects of two isolates; Trichoderma harzianum and Trichoderma virens, and biological toxin of Trichomax-HV against Fusarium oxysporum f. sp. lycopersici which is the agent of Fusarium wilt disease in tomato was evaluated in the laboratory and greenhouse. Trichomax-HV is a biofungicide that use as commercially. During summer and autumn, tomato plants with obvious signs of Fusarium wilt were collected from tomato fields in different parts of Lorestan province and transferred to the laboratory. Isolation of pathogenic fungi was performed according to Bani Hashemi and Dezeeuw methods using acidic PDA culture medium. Antagonistic activity of these isolates against this pathogen was studied by dual culture method in the laboratory. In order to investigate the effect of these antagonist isolates in the greenhouse, first the inoculum of pathogenic fungus and fungal antagonists were added to the pots as soon as the seedlings were transferred to the pots and then after 60-days, the interactions between the pathogen and antagonist was evaluated. This test was performed in a completely randomized design with 10 treatments and three replications. The data obtained from the experiment were statistically analyzed using SPSS 16 software and the average of the treatments were compared using Duncan's multiple range test at 5% probability level.

In this study, a total of three isolates of F. oxysporum f. sp. lycopersici were isolated from tomato plants infected with Fusarium wilt disease from Robat and Chegeni Dore tomato fields (Khorramabad city) and Cham fig fields (Poldokhtar city) that was assigned them codes FOM, FOK and FOS respectively. A total of 27 fungal isolates were isolated from soil samples of tomato rhizosphere collected from tomato fields of two cities in Lorestan province. By evaluating the inhibitory effect of these isolates on pathogenic growth, two isolates prevented the growth of pathogenic mycelium by creating an inhibitory aura. The results of laboratory studies showed that T. harzianum by 48.9 percent, Trichomax-HV by 45.6 percent and‏ T. virens to 22.36 percent prevented the growth of pathogen and colonized the pathogen’s colonies (in comparison with the control). Antagonist agents in greenhouse experiments increased stem height, wet and dry weight of shoots and root in the absence of pathogen. Comparing with the control sample, only the isolate T. harzianum in the interaction with the pathogen increased the plant height, wet and dry weight of shoots and root. According to study, in the greenhouse biological tests of biofungicide (Trichomax-HV) and Trichoderma spp. had shown good control on causal agent of the disease (Fusarium oxysporum f. sp. lycopersici). Among these treatments, T. harzianum had the best effect on the control of pathogenic fungi, which is due to the complex system of soil biology and ecology and the presence of antagonists in the rhizosphere and the power of root colonization and antagonist survival, soil pH and soil texture.

Based on the this study results, T. harzianum had the highest percentage of inhibition of pathogenic fungal growth as well as increase in height, fresh and dry weight of the plant and decrease in disease severity among the different treatments tested. In greenhouse conditions, T. harzianum prevented from tomato Fusarium wilt disease (caused by Fusarium oxysporum f. sp. lycopersici) in very large extent. Also this results showed that Trichomax-HV could be a viable alternative to chemical fungicides in controlling this disease.

Plant-parasitic nematodes cause significant yield losses in a wide range of crops. Root-knot nematodes (Meloidogyne spp.) are the most important plant-parasitic nematodes, because they widely distributed all around the world and have wide host range. Chemical nematicide is one of the primary means of control for plant-parasitic nematodes. Due to negative impact of synthetic nematicides, it will be necessary to develop other management strategies for plant-parasitic nematodes which are safe for the environment and humans. Latest interest in organic farming lead to substitution for conventional nematicides by low-risk compounds such as natural products derived from plants. Also, biological control is an interesting option to control these nematodes. Effective microorganisms (EM®) consist of a mixture of live cultures of microorganisms such as photosynthetic bacteria, which they are reported to reduce the incidence of pathogenic microorganisms.

In the present study, the aerial parts of the marigold (Tagetes erecta) were collected from Shiraz, Iran. Marigold leaves dried in shade and finely grinded using an electric grinder and a stock solution (10% w/v) was prepared. Seeds of tomato (cv. Early-Urbana) were sown in plastic pots containing 1500 g of a sterilized mixture of farm soil (sandy loam soil) and cow manure. The pots were kept under greenhouse conditions with 16:8 h light to dark photoperiod and 27 ± 4 °C. Four-leaf stage seedlings were soil-drenched (50 ml per plant) with EM® or a mixture of equal amount of EM®+ marigold leaf extract at the rate of 5, 10, 15 and 20% and simultaneously inoculated with a suspension of M. javanica (6000 eggs per pot). The experiment was carried out in a completely randomized design with five replications. Sixty days after nematode inoculation, plants were harvested and the vegetative indices including shoots length, shoot fresh and dry weight and root fresh weight and the nematode population indices including the number of eggs as described by Hussey and Barker (1973), number of galls and egg masses per root system as described by Taylor and Sasser (1978) and the number of second stage juveniles (J2s) in the pot were recorded. Finally, the reproduction factor calculated as described by Sasser and Taylor (1978). Data were subjected to one-way analysis of variance (ANOVA) for plant growth parameters and two-way ANOVA for nematode population indices using SAS 9.1 program (Statistical Analysis System Institute Inc., USA). Treatment means were compared using least significance differences (LSD) at p<0.01.

Results showed that soil drenching of EM® and EM®+ marigold leaf extract increased the plant growth parameters on inoculated and non-inoculated plants as compared to control. The treatment with EM®+ marigold leaf extract at the rate of 20% was the most effective treatment and increased shoot length, shoot fresh weight and shoot dry weight of non-inoculated plants by 33, 39 and 11% respectively, as compared to non-inoculated control plants. In the case of inoculated plants, shoot length, shoot fresh weight, shoot dry weight and root fresh weight of treated plats with EM®+ marigold leaf extract at the rate of 20% were 34, 31, 15 and 11% higher than inoculated control plants. The number of eggs and egg masses per root system and the reproduction factor were significantly reduced in treated plants with EM®+ marigold leaf extract at the rate of 15 and 20%. EM®+ marigold leaf extract at the rate of 20% reduced the number of eggs, galls, egg masses per root system and the reproduction factor by 28, 40, 37 and 27% respectively, as compared to control. The lowest numbers of egg masses were observed in the root system of tomato plants treated with EM®+ marigold leaf extract at the rate of 20%. It had significant difference than other treatments, except EM® at the rate of 20%. These data for the first time in Iran, suggest that EM® might have utility in controlling root-knot nematodes. A mixture of EM® and marigold leaf extract was more effective than alone application of EM® for control of M. javanica. Findings from this study, suggest that a mixture of equal amount of EM® and marigold leaf extract at the rate of 20% reduced M. javanica reproduction rates in tomato plants grown in greenhouse.

Three mite species (Panonychus citri (McGregor)), Phyllocoptruta oleivora (Ashmead) in Caspian costal region in north part Iran and Eutetranychus orientalis Klein in southern part of the country playing major mite pests role in citrus orchards. An increase of Panonychus citri population activities onset with spring season and this mite damages on leaves and greenhouse shield of different citrus species mostly occurred during middle part of spring season and extended up to late summer season under low amount and number of rainfalls happened. At present control of this mite damages on citrus spp mostly depended to pesticide application in various citrus orchards in Mazandaran and other neighboring citrus growing provinces. Moreover, the highest amount of acaricides used in Mazandaran province applied for control of citrus mite pests only. To avoid further P. citri population resistance to limited number of pesticides available in market, introducing, a new compound of acaricide which being effective on eggs and active stages of this mite pests is necessary for sustainable mite pest management program.

In this study, effects of two doses (0.2, 0.3 ml) of Envidorspeed 24% SC were investigated in comparison to registered acaricides (Spirodiclofen 240 SC, 0.3 ml/l, Abamectin 1.8% EC, 20ml+250ml horticultural oil/100l water, Fenpyroximate 5% SC, 0.5 ml/l), organic pesticides (Biomite 2.5ml/l, Mineral silicon liquid 5%), detergent (Detergent of Goli 1.5%), Control treatment (water sprayed) were investigated on P. citri active stages in eastern and western parts of Mazandaran province. Those pesticides applied at the time of observing 5 active mite stages observed in 30 % of infested leaves collected randomly. Number of mobile mite stages on upper surface of 48 citrus leaves randomly collected from each treatment, mobile mites counted and registered with the help of stereomicroscope at laboratory conditions. Collected raw data of mite at one day before, 3, 7, 14 and 21 days after treatments converted with Henderson-tilton formula into mortality%. Statistical analysis variance on mean mortality% done with SAS software and grouping of those treatment carried out according Duncan multiple range test methods. Side effects of those treatments on citrus natural enemy’s trees (mostly predatory mites from Phytoseiidae, Tydeidae, Cunaxidae, Stigmaeidae, Erythraeidae, and Trombidiidae) and few predatory insects, evaluated by data collected one day before treatments with data of natural enemies collected 21 days after treatments. Quantities damages of this mite pest on citrus fruit weight were also evaluated from end of leaves sampling treatments for toxicities at interval of one month during 3 months sampling period. Amount of mite damages in each treatment determined by random collection of 16 citrus fruits from middle part of citrus trees of each treatment and weighted them at each interval time until harvesting time in autumn season.

Result of both Envidorspeed doses efficiency in control of citrus red mite caused absolute mite control (100%) through sampling period of time. Mean population of 8.01 mite active stages recorded on upper surface of orange leaves did not influences on mite mortality % in eastern part of Mazandaran province. The organic treatments effects (Biomite 2.5ml/l, Mineral silicon liquid 5%) on citrus mite pest observed almost identical to effects of those registered acaricides applied in this study. The mite mortality% in eastern part found higher than western part of province. The different caused by this phenomena, mostly related to higher rate of rainfall in west than east part of this province as decreasing toxicity of pesticides affects. Maximum and minimum number of natural enemies as compared to controlled treatment were recorded for 0.3 ml/l of Envidorspeed dose and biomite organic pesticide, detergent (Goli 1.5%) treatments respectively. Less side effects of treatments toxicity recorded on an Oribatida mite (Scheloribates sp.) population, whereas harmful effects of them observed on two species of phytoseiid mite family (Amblyseius herbicolus, Typhlodromus caspiansis). Statistical analysis of citrus red mite damages on weight of citrus fruits at different treatments compared with control treatment did not showed a significant differences (p>0.05) and all treatment remained in a same group according Duncan method. According published articles, proper rate of citrus red mite damages on oranges or other citrus species remained unknown.

This finding suggested that, if lower Envidorspeed dose (0.2ml/l) applied at early stages of citrus red mite population, up to 33% cost of pesticide will reduce, protect further environmental pollution at citrus orchards which broadly scattered through Mazandaran province.

Cucumber, Cucumis sativus L. is one the most important economic vegetables crop cultivated in Iran and many countries of the world. The cotton-melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is one of the most destructive polyphagous pests of Cucurbitaceae plants in greenhouses and open fields. A. gossypii can cause severe damage in commercial fields. The honeydew that aphid excretes decreases the photosynthetic activity of plants and contaminates fruit, resulting in severely reduced quality. Moreover, A. gossypii can transmit more than 80 type of viral diseases that can cause substantially greater losses than the damage from direct feeding of the insect. The focus of the control methods against this pest in our country is the use of insecticides. Additionally, A. gossypii has developed different levels of resistance to many insecticides. Agricultural adjuvants can improve the efficacy of pesticides and can be effective in reduction of pesticides use. In the current research, the effects of two adjuvants (Scorch and Torpedo п) on efficiency of imidacloprid (SC35%) and flonicamid (WG50%) to control this aphid were investigated on cucumber in greenhouse. These two insecticides have systemic property doing their job after leaf penetration. It is known that the leaf penetration step is very determinative for systemic pesticides. Besides, Scorch and Torpedo п are multi-functional adjuvant, showing penetration, wetting, adhesion and spreading properties.

The project was performed based on a completely randomized design with 15 treatments and 3 replicates. The efficacy in the sampling units was recorded at 1, 3, 7 and 14 days after treatment. The treatments were: 1) imidacloprid (recommended dose); 2) imidacloprid+Scorch; 3) imidacloprid+Torpedo п; 4) imidacloprid (10% reduction of dosage)+Scorch; 5) imidacloprid (20% reduction of dosage)+Scorch; 6) imidacloprid (10% reduction of dosage)+Torpedo п; 7) imidacloprid (20% reduction of dosage)+Torpedo п. Flonicamid was replaced by imidacloprid in the treatments 8 to 14. The control treatment (No. 15) was sprayed by water only. The efficacy was calculated using the Henderson and Tilton formula. Statistical analysis was performed using the SAS software (ver. 9.1). One row was considered as the distance between the experimental units. Two rows on either side of the greenhouse were also considered as margins.

The combine analysis of variance showed that interaction of treatment × place was not significant, meaning that the experimental treatments had the same respond in different locations. Therefore, the data were statistically analyzed based on this, without considering the locations (Urmia and Karaj). The results showed that both adjuvants were able to improve the efficacy of imidacloprid and flonicamid, as it was confirmed at all times after spraying. For example, three days after spraying, the efficacy of imidacloprid alone was estimated at 81.47%, while "imidacloprid + Torpedo" and "imidacloprid + Scorch" were estimated at 92.60% at 93.43%, respectively. Similarly, seven days after spraying flonicamid alone showed 87% efficiency, whereas the treatment of "flonicamid+Torpedo" and "flonicamid+Scorch" exhibited 94.34% and 95.31%, respectively. When Torpedo п was used in combination of reduced doses of imidacloprid, the efficacy was severely reduced. Thus, the addition of Torpedo п is not recommended with reduced doses of imidacloprid. Instead, adding the Scorch when reducing the imidacloprid dosage, the efficacy was remained as high. For example, three days after spraying, "Imidacloprid with 10% dose reduction + Scorch" and "Imidacloprid with 20% dose reduction + Scorch" treatments were 93.65% and 94.23% efficacy, respectively. Besides, by reducing the flonicamid dosage and adding both adjuvant, the efficiency was as high as to the treatment using the recommended dosage. For example, 14 days after spraying, flonicamid with 10% dose reduction + Scorch and flonicamid with 20% dose reduction+ Scorch showed 93.94% and 93.48% efficacy, respectively. Our results can be important from both economic and environmental point of view, as the obtained results indicated that imidacloprid and flonicamid dosage can be reduced by 20%. However, it should be keep in mind that other factors, such as the price of adjuvants, are involved in their practical and field use by farmers, which should be taken into account.

Cabbage aphid, Brevicoryne brassicae (L.), is one of the most important and harmful pests of crucifers, which is active in many parts of Iran and causes quantitative and qualitative damage in the cultivation of these plants during the winter. Some natural enemies such as the parasitoid wasp Diaeretiella rapae (McIntosh) are active on this pest. The indiscriminate use of insecticides for controlling pests caused evolution of pest resistance, environmental pollution and negative effects on natural enemies and beneficial insects. In recent years, environmentally compatible factors have received more attention due to less side effects in pest control. This study was carried out to determine the effects of the entomopathogenic fungus Beauveria bassiana (Bals.), and nanosilica separately and in combination on survival of the cabbage aphid and its parasitoid treated by different concentrations of fungus (103, 104, 105, 106 and 107spore/ml) and nanosilica (125, 250, 500, 1000 and 2000 ppm).

Cabbages (Brassica olearaceae var. capitata) were grown from seed in plastic flower pots. Aphids were collected from Brassicaceae plants in fields of Nazlo Campus of Urmia University near Urmia city. This colony was used as a source for all aphids used in all laboratory experiments. Also, a colony of D. rapae was reared on B. brassicae under greenhouse conditions. Wasps were fed a 10% honey solution and used to parasitize aphids, or for use in experiments, 24 hours later.Fungi was cultured on Sabouraud Dextrose Agar (SDA) in petri dishes (6 cm in diameter) and incubated for two weeks to induce sporulation. Spores were harvested from the surface of 14-day old culture and transferred to a test tube containing sterilized distilled water with 0.05% Tween®-80. The conidial concentration of final suspension was determined by direct count using a neubauer hemocytometer and serial dilutions were made to obtain different conidial concentrations. Sio2 nanoparticles of pashgamannano® company was used in bioassay tests. Bioassay test was carried out on aphid and its parasitoid. Aphids were treated by conidial concentrations using dipping method. Control adults were treated with distilled water containing 0.05% Tween®-80. In order to evaluate the effect of nanosilica on aphids, leaf discs were dipped in to different concentrations of nanosilica and after drying, adult cabbage aphids were transferred on treated leaf discs in Petri dishes. The mortality was counted 24, 48 and 72 hours after treatment. Experiments were carried out at 25±2 Co temperature, 65±5% RH and a photoperiod of 16: 8 h. (L: D) under laboratory conditions. LC25, LC50 and LT50 values of fungi and nanosilica were estimated. Also, combination effects of fungi and nanosilica were evaluated in laboratory. A preliminary test was evaluated to determine side effects of different concentrations of nanosilica on viability and germination of fungi spore. Germination rate for fungi was calculated after 24 hours. The LC25, LC50 and LT50 values (with 95% confidence limits) were calculated using the Probit analysis method. Bioassay data were subjected to one-way analysis of variance (ANOVA) after checking for normality and means were compared by Tukey’s test.

The LC50 values obtained from the analysis of probit as a result of the effect of different concentrations of B. bassiana 7 days after treatment and nanosilica 24, 48 and 72 hours after treatment on cabbage aphid were 2.2×105 spore/ml and 4356.14, 1164.42, 487.19 ppm, respectively. Furthermore the LC50 values of B. bassiana 4 days after treatment and nanosilica 24, 48 and 72 hours after treatment on D. rapae were 1.2×106 spore/ml and 3639.79, 619.51, 289.77 ppm, respectively. Results showed that the adults of the cabbage aphid were completely sensitive to the fungal isolate. The shortest time needed for the mortality of 50% of the population of cabbage aphid was 5.02 days at 107 conidia/ml concentration. The mortality rate of nanosilica at highest concentration, 72 hours after treatment was 90 and 96.6% respectively for cabbage aphid and parasitoid wasp. Also, combination of these factors against adults of cabbage aphid had significant difference with control.

According to the results of this study, it can be concluded that B. bassiana and nanosilica are effective on cabbage aphid and can be used as effective factors in the integrated pest management program of this pest.

Knowledge of weed biology helps to optimize weed management strategies and avoid unnecessary weed control input by for example accurate prediction of emergence timing of the weeds. According to the available references, 200 species of dodder have been reported in the world of which 18 species are in Iran. Among the 18 reported species in Iran, Cuscuta campestris and Cuscuta monogyna cause the greatest damage to crops and horticultural products in Iran. Cuscuta monogyna (Vahl), a member of the Cuscutaceae family, is a non-specific aboveground holoparasite, and as such is totally dependent on its host plant for assimilates, nutrients and water supply. Eastern dodder is one of the important dodder species that parasite fruit trees and ornamental shrubs. Each eastern dodder plant produces greater than 3000 seeds of which low percentage germinate in the first year. In the field, dodder started to germinate in March or April when daily average soil temperatures reached 10°C, and maximum germination was observed in May or June when daily average soil temperatures reached 20°C. After germination, seedlings of Cuscuta spp. Undergo a non-parasitic phase of growth, dependent on seed reserves, for 2–3 weeks. To improve management systems for specific weed species, it is critical to have good information on seed dormancy, persistence, production, seasonal germination, seedling emergence, and variations among populations. The objective of the present study was to effect of temperature and salinity on two eastern dodder (Cuscuta monogyna Vahl) ecotypes seed germination characteristics.

In order to study the effect of salinity and temperatures on seed germination chrachteristics of two eastern dodder ecotypes experiments were conducted based on factorial in a completely randomized design with three replications in the Research Laboratory of Ferdowsi University of Mashhad Faculty of Agriculture during 2015 and 2016. Treatments include salinity stress in 8 levels (0 (Control), -0.1, -0.2, -0.4, -0.6, -0.8, -1 and -1.2 Mpa) and temperature at 8 levels (5, 10, 15, 20, 25, 30, 35 and 40oC). After 14 days, seeds in treatment solutions were no longer germinating, so all germinated seedlings were removed and un-germinated seeds of the highest salinity treatment (-1.2 Mpa NaCl) were rinsed with distilled water and placed back in their dishes with 5 mL of distilled water for 14 more days.

Results showed that with increasing salinity at each level of temperature germination rate and percentage reduced in both ecotypes, so that in potential -1.2 Mpa germination was stopped in both ecotypes. In both ecotypes germination stamped at 5, 10 and 40 ̊C temperatures in all levels of salinity. In both ecotypes the highest percentage and rate of germination were indicated at control treatment salinity and 25 and 30 ̊C temperatures. It is believed that the effect of high concentration of NaCl at high temperatures can be attributed to the toxic sodium that causes irreversible damage. According to the results Bardaskan ecotype was better than Qouchan ecotype in view of germination at high levels of temperatures and salinity treatments. The three parameter logistic model provided a satisfactory fit for the response of seed germination to NaCl concentration. The effective salinity for reducing of 50% seed germination in Qouchan ecotype at 15, 20, 25, 30 and 35 ̊C temperatures were -0.79, -0.86, -0.87, -0.77 and -0.68 Mpa and in Bardaskan ecotype were -0.93, -0.93, -0.95, -0.90 and -0.75 Mpa respectively. Recovering the ungerminated seeds from the salinity level of -1.2 Mpa and reincubating them with distilled water resulted in a germination of 70% in both ecotypes, indicating that enforced seed dormancy was mainly because of an osmotic effect, as opposed to toxicity owing to an ionic effect.

This study shows that eastern dodder has capacity to survive and reproduce even under a higher temperature and higher degree of salinity stress. The information of this study would be helpful for estimating the potential of this species to spread to new areas and for the improvement of this parasitic weed species management programs. As is evident from these experiments, the effective, long-term reduction of eastern dodder populations will require the use of an integrated weed management approach.

Oilseeds are the second largest food sources in the world after cereals. Soybean (Glycine max L.) is the largest source of protein and oil in the world and is cultivated in some regions in Iran. Golestan province is one of the important agricultural regions in Iran with about 62.01% of the soybean cultivation area. Most of these areas are located in Gorgan County. There are a number of approaches that they use to management of weeds in agroecosystems. Management and protection of crops from weed damage depend on our knowledge about weed richness and their distribution status. For this purpose, generation of weed distribution maps provide very important information for weed management. Also, determination of weed flora help to managers and farmers to identify weeds and select the best method for weed control, especially invasive weeds in soybean fields. Therefore, the aim of study was to determination of flora and distribution of weeds in the current soybean fields in Gorgan County.

This research was carried out in 48 soybean fields of Gorgan County, during 2015-2016. In the field section, the W method used to collect weed samples in order to calculate the number, frequency, species density, etc. The spatial information of the fields was recorded by GPS and sampling was done by 0.25*0.25 square meters quadrate. Total weed samples moved to weed research laboratory of Gorgan University of Agricultural Sciences and Natural Resources (GUASNR) and identified in terms of scientific and family names based on taxonomical classification way. Then, all data entered to Microsoft Excel spread sheets var. 2010, and were averaged and arranged. In order to determine the weed flora status of these fields, some indices such as frequency, relative species frequency, species uniformity, relative species uniformity, density and relative species density were calculated. To better display of distribution maps, weeds were divided based on frequency index into three categories; 50-100%, 50-30% and less than 30% and weeds with a frequency of 50-100% were considered as important weeds of soybean fields in Gorgan. Finally, the data were processed in ArcGIS software var. 10.3, and then weed distribution maps of soybean fields were generated.

In this study, 21 types of weeds were identified from 14 plant families, which 14.28% were belonged to perennials group and the rest amounts were annual weeds. Also, 76.19% were belonged to dicotyledons and about 23.81% were monocots. The highest density was related to ground cherry (Physalis divaricate L.) with 16.68% compared to other weed species in the measured plots. Crab grass (Digitaria sangunalis L. Scop.) with a density of 0.94 and sorghum (Sorghum halepense L. Pers) with a density of 0.78 had the highest density than other weeds. The weeds of the studied fields included 23.80% of narrow-leaved weeds and 76.19% of broadleaf weeds. In terms of photosynthetic cycle, 28.57% of weeds classified to C4 cycle and 71.42% to C3 cycle. Also, the most important plant family was Poaceae with 19.04% of the observed weeds in soybean fields, compared to other plant families. The most dominate species of this family are sorghum, cockspur grass (Echinochloa crus-galli L. P. Beauv) and crab grass. The weeds with a frequency of 50-100% were included ground cherry, sorghum and wild melon (Cucumis melo var. agrestis L.) with a frequency of 91.66, 54.16 and 52.08%, respectively. Results of weed distribution maps showed that weeds with frequency of 50 to 100% were observed in the most of surveyed field and they were distributed across the county, from east to west.

In the study, the weed distribution maps showed the existence of broadleaf weeds such as ground cherry, sorghum and wild melon in the most of the studied fields. Also, we identified the large number of weed families in this study. Considering this high number of identified weed and the presence of some invasive weeds in the surveyed fields, these results can useful for weed management programs of soybean fields and other crops in Gorgan County. Therefore, it is necessary that farmers and agricultural managers of the Gorgan County care to distribution of invasive weeds. Finally, it concluded that a combination of local and longer-term weed management can possible to deliver reduced weed infestation levels. Also, integrated weed management is an essential practice for reducing the impact of pesticides in the agroecosystems.

Intercropping involves growing more than one crop in the same field at the same time. Intercropping increase diversity in the cropping system and enhance the utilization of resources such as light, heat and water. This practice can also help to suppress weeds and increase the likelihood of being able to reduce herbicide use in the cropping system. Alternatively, in organic systems where herbicides are not used, intercropping can reduce the yield loss potential and provide stability in the system. In recent years, native cotton growers in Khorasan region, especially in Torbat-e Jam region, using the intercropping of cotton-fodder beet (Beta vulgaris subsp. vulgaris L.), while facilitating the growth of fodder beet plant providing forage for livestock and increasing land income in the cotton crop. Placement of fodder beet plants in or between rows of cotton cultivation accelerates the conquest of space and resources compared to cotton monoculture. Little information is available on the cultivation of fodder beet - cotton intercropping and its effects on the yield of both plants, as well as the potential of this crop system in weed control. Therefore, this experiment was designed with the aim of the effect of cotton- fodder beet intercropping on weed control and evaluation of intercropping and competitive indices in Mashhad region.

In order to evaluate the effect of cotton-fodder beet intercropping on weed suppression, a split factorial experiment was conducted based on a randomized complete block design with three replications at Ferdowsi University of Mashhad research farm. Treatments include intercropping pattern at two levels of inter-row and intra-row intercropping and the ratio of cotton-fodder beet substitution intercropping at five levels including 75: 25, 50: 50, 25: 75 and monoculture of cotton and fodder beet as the main factor and weed interference at two levels including weeding and non-weeding throughout the weed season as a secondary factor. Land equivalent ratio for cotton, land equivalent ratio for fodder beet, total land equivalent ratio , actual yield loss for cotton, actual yield loss for fodder beet, total actual yield loss, relative value total for cotton, relative crowding coefficient for cotton, relative crowding coefficient for fodder beet, total relative crowding coefficient, aggressivity, competitive ratio for cotton, and competitive ratio for fodder beet were the indices which calculated and used as a basis for the evaluation of cotton – fodder beet intercropping. Analysis of variance was performed using generalized linear models through GLMMIX procedure in SAS 9.4 software environment. The effect of three factors: intercropping pattern, intercropping ratio and weed interference and their interaction with each other were considered as fixed effects and block and block effect, mixed intercropping pattern, intercropping ratio and total error were considered as random variables in the model. Comparison of means of the simple effects of factors and their interaction were performed using the least squares mean comparison method in the same procedure.

The results showed that the effect of intercropping pattern and intercropping proportion on total weed density was not significant, but was significant on total dry weight of weeds, although it was still not significant compared to monoculture of cotton. Accordingly, at a 25: 75 crop proportion of cotton - fodder beet, the dry weight of weeds was lower than other intercropping proportion. Also, the effect of intercropping pattern on both crop traits was not significant, but the ratio of intercropping on cotton and fodder beet traits was significant. In terms of interference or non-interference of weeds, at least 50% reduction in cotton lint yield and 83% reduction in fodder beet root yield was observed in intercropping conditions, compared to monoculture of each plant. The two indices of land equivalent ratio and actual yield loss showed the superiority of cotton monoculture over intercropping, but the relative value total index expressed the superiority of cotton-fodder beet intercropping over cotton monoculture. So that intercropping of cotton-fodder beet with a ratio of 75:25, in the presence and absence of weeds, the relative value total increased by 2.5 and 8.6 times, respectively, of cotton monoculture. Competitive indices including relative crowding coefficient, competition ratio and aggressivity index showed that fodder beet has higher competitive power than cotton. In general, the results of this experiment showed that cotton-beet forage intercropping, although it had no significant effect on weed control, is still recommended in terms of mixed crop evaluation indicators.

In general, the results of this experiment showed that the cotton-fodder beet intercropping, as replacement pattern, had no significant effect on weed control, and considering that it was suitable only in terms of one of the evaluation indices (relative value total), it is not generally recommendable.

Among crops, wheat is one of the most widely cultivated crops in the world that supply about 60 to 70 percent of the world population's food energy. Among the factors reducing crop production, weeds are particularly important, and they could reduce crop yield through competition for water and food and also by disrupting the harvest. It is important to assessment of weed-crop competition mechanism to get vital resources as well as assessment useful crop features for increasing competition with weeds. One of these methods could be use of cultivars with high-ability competitors against weeds. So in this regard, awareness of weed-crop competition aspects in addition to yield losses due to weed competition, will leading to a reduction in herbicide application.

To evaluate the effect of wild mustard competition on morphological characteristics, yield and yield components of wheat, a factorial experiment was conducted based on a randomized complete block design with three replications in Islamic Azad University Shoushtar Branch in 2016. In the experiment, the treatments were type of competition between weed and wheat that was included: a) the shoots competition of weed with wheat cultivars b) the root competition of wild mustard with wheat c) the shoot and root competition of wild mustard with wheat cultivars and d) no weed competition as control and wheat cultivars was included: Chamran, Karim and Vrynak.

Analysis of variance showed that all the studied traits were significantly different from each other. Results showed that the maximum height (95 cm) was observed for Chamran cultivar in control treatment and the minimum height (74 cm) was for Vrynak in the shoot and root competition of wild mustard with wheat cultivars. A comparative evaluation of interaction effects showed that the highest root length (13.3 cm), number of fertile tillers (2.1) and spike length (11.6 cm) were obtained in Chamran cultivar in control treatment. The least of these traits was observed in Vrynak cultivar in the both shoot and root competition of wild mustard with wheat cultivars. The results showed the largest decrease in the number of seeds per spike (40.95 percent compared to control) and spike number per m2 (17.62 percent compared to control) was obtained in the treatment of shoot and root competition of wild mustard with Vrynak cultivar. The study showed that the highest 1000-grain weight (40 g) was obtained in Chamran and control treatment and the least was obtained in the treatment of shoot and root competition of wild mustard with Vrynak cultivar. The highest grain yield (497.45 g m-2) and biologic yield (1784.39 g m-2) were obtained in Chamran and control treatment, while, the lowest ones (150.25 g m-2 and 1026.31 g m-2) were obtained in the treatment of shoot and root competition of wild mustard with Vrynak cultivar, respectively. Reduction in wheat yield was occurred due to decreasing the number of spike, number of grains per spike and 1000-grain weight. Assessment the results of biological yield and grain yield in wheat cultivars showed that compared to economic performance of wheat, total dry matter production was less affected by wild mustard interference.

Overall, in this study, the highest amount of morphological traits, yield, and yield components were obtained in combined treatment of Chamran and control. Accordingly, Chamran due to higher economic performance both in weed-free and weed-interference conditions could be as a competitor cultivar in agricultural operations and its properties could be used in breeding.