Iranian Plant Protection Research
Year:2017 | Volume:31 | Issue:2 |Papers Count:23

Introduction: Aphids are tiny soft-body insect pests which damage the host plant directly through sap feeding and indirectly by transmission of plant viruses. Pomegranate green aphid, Aphis punicae is a common pest of pomegranate gardens in Iran. In some years, the aphid dramatically damages under the suitable conditions in that they can grow and reproduce. Lady beetles are small, brightly colored insects and belong to family Coccinellidae. These predators obtain necessary resources for their survival and reproduction from a variety of habitats.Menochilussexmaculatus (Col.: Coccinellidae) is one of the major predators of pests reported in the gardens of Iran. The zigzag beetle is a general entomophagouscoccinellid that feeds upon soft body insects such as aphids. The adults ofM sexmaculatus are bright yellow in color with black vertical zigzag lines. The adults and larva prey upon all stages of aphids. The study of the predation efficiency ofM. sexmaculatus would increase its chances to be used as a biological control agentM. sexmaculatus is an efficient predator of many aphid species, e.g. the mustard aphid, Lipaphiserysimi Kalt. The zigzag, beetle widely distributed and feed on aphid species in India, Pakistan, Borneo, Jawa Indonesia, and the UK. The Philippines, Islands of Bali, France, Sumatra and South Africa. In this paper, we evaluated the effect of temperature on some biological parameters of M. sexmaculatusby feeding on pomegranate green aphid, A.punicae. Menochilussexmaculatus is an effective predator to be used as a bio-control agent but the major challenge is its mass rearing and augmentation Materials and Methods: The colony of M. sexmaculatus was established from about 100 adult beetles collected from a pomegranate orchard (GPS coordinates 30°23' 42.31' ' N and 55°56’51.11’ E) at Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran, in October 2013.. Adults were held In a ventilated plastic box (25.0 x 20.0 x 10.0cm) and fed by pomegranate green aphids in a climate-controlled growth chamber set to 25 ± 2 °C, 65 ± 5% RH and 16L: 8D photoperiod. The functional response of different stages ofM.sexmaculatus to different densities of 3rd and 4th nymphal stages of pomegranate green aphid were studied at temperatures of 20, 22.5, 25, 27.5 and 30 (±1) °C, for adult females (10-days old) in temperatures of 25 and 27.5 (±1) °C for 3rd and 4th larval stages, at 65 ± 5 RH and 16: 8 L: D photoperiod. The densities of 2, 4, 8, 16, 32, 64, 100, and 128 3rd and 4th nymphal stages of aphid for 3rd and 4th larval stages and densities 8, 16, 32, 64, 100 and 128 for female and male adults. Females of lady beetle were used and the average feeding at any density was recorded after 24h.Type of functional response was determined using logistic regression and the searching efficiency (a) and handling time (Th), were estimated by nonlinear regression. All the data in the Excel 2007 program was set.Curves and graphs were plotted using Excel 2007 software.Results and Discussion: Type of the functional response of the all predator stages across all temperatures was type II. The results showed that the temperature is effective on functional response of predator, and searching efficiency of predator increased at temperatures of 22.5°C to 27.5°C. The maximum and minimum value of the searching efficiency were0.14 h-1 at 27.5°C and 0.0582 h-1 at 22.5°C and of handling time were 0.26 h at 20°C and 0.0182h at 22.5°C for adult females respectively.ConclusionIn general, the lady beetle at temperature of 27.5°C and in stages of 4th larval and adult would have the highest predatory efficiency. Application of this predator was interested in biological control programs of pomegranate green aphid. The data indicated that theM. sexmaculatus may be a useful candidate for the biological control ofA. punacae in pomegranate gardens.

Introduction: Canola (Brassica napus L.) is one of the prominent oil seed plants in Iran. This plant has good agricultural and food nourishment properties, such as resistant to drought, cold and salinity stresses and low level of cholesterol. Cabbage waxy aphidBrevicorynebrassicae (L.) is the most important and cosmopolitan pest of cruciferous crops. This aphid is reduced 9 to 77% grain yields and up to 11% oil content. Developing environmental-friendly methods, such as deploying insect-resistant varieties to pest control was advised by scientists. Resistant varieties decrease production costs and can be integrated with other pest control policies in IPM programs. In a greenhouse experiment plants of cabbage, cauliflower wassusceptible host plant and broccoli, turnip, rapeseed, showed resistance to cabbage aphid. With the aim of identifying the existence of resistance resources, a laboratory study was conducted to evaluate the effects of seven canola genotypes on biological parameters of cabbage aphid. Detected resistant variety could be used as a resistance source.

Introduction: Grapevine belongs to the Vitaceae family that consists of 14 genera and about 700 species.Only in the genusVitis fruits are edible. Italy is the largest producer of grapes and Iran has the seventh position in the world from this point of view. Western Azarbaijan province comprises a high diversity of crops including wild grapes. Although, some nematodes are free living and antagonists of another soil microfauna, the other are plant parasitic agents. Most of which live in the agricultural soils where they are widely dispersed. Effectiveness of the disease management strategies are affected by the accurate identification of the plant disease causal agents and the nematodal diseases are not the exception from this rule. Therefore, for control of the diseases caused by the nematodes, it is necessary to separate the parasitic nematodes from the suspected contaminated soils and identify them. Although separation and identification of the nematodes are partly time-consuming, it is not very complicated. Some nematodes likeXiphinema, Longidorus and Ditylenchus are cosmopolitan and catastrophic nematodes in vineyards worldwide. So far no study has been performed regarding the plant parasitic nematode in vineyards of the south of Western Azerbaijan. Therefore, in this study as an introduction to the management ofthe vineyard parasitic nematodes, the dominant nematodes of the plant were identified. In the next step, investigation of nematodes bioecology, the interaction of nematodes with the other plant pathogens, their host range and their damages to the host plants would be studied.

Introduction: Weed control is the most important challenge for adoption of conservation tillage systems.Tillage prepares optimum conditions for growth and development of crops. Conservation tillage compared with conventional tillage has many advantages in terms of improving soil conditions and soil moisture retention.Nevertheless, during the preparation of seed bed, decreasing of soil disturbance in different conservation tillage methods could be resulted in optimal conditions for growth of various weeds. Although each of the conservation tillage methods affect on weed population dynamics and change weed density and diversity, the effects of tillage systems on weed dynamics and diversity depend upon species, location and environment which is complex and not fully understood.

Introduction: The genus of oat contains several species often infesting both wheat and barley fields all over the world. They compete tightly with these crops for space, water, nutrients, and light. Due to a continuous high selection pressure, herbicide resistance to ACCase inhibitors developed in wild oat populations. Accordingly, these observations approved the necessity of replacement of ACCase-inhibiting herbicides with other herbicide modes of action. The sulfonylurea herbicides were assessed as good alternatives for this purpose. Due to sulfonylurea herbicides ability to control a broad spectrum of grass and broad-leaved weeds, combined with their low application rate and low mammalian toxicity. The efficacy of herbicides can be enhanced using surfactants (1 and 18).

Introduction: The pink hibiscus mealybug, Maconellicoccushirsutus (Green) (Hem.: Pseudococcidae) is one of the serious economic pests of agricultural crops in tropical and subtropical regions.This pesthas spread through Asia, Africa, America and Australia, and infests more than 330 host plants which some of them have the important role in theeconomy. This sap-feeding insect secrets honeydew which provides suitablemedium for black sooty moldgrowth. It also releases a toxin during feeding, which results in severe stunting, decline, and deformation of twigs. It has recorded as a pest on different host plants in southern Iranian provinces since the 1990s.In Khuzestan province, it was first observed on Chinese hibiscus shrubs in urban landscapes of Ahvaz in February 2009. The evergreen hibiscus shrub is very common in the urban landscape of warmcities of Khuzestan province. The severity of mealybug damage to hibiscus shrubs causedto becut off in some regions. As there is no data on the biology ofM. hirsutus in Iran, in the present study, the biologyof this pestwas investigatedat different temperatures in laboratory conditions as well as its population fluctuations on Chinese hibiscus shrubs in urban landscapes of Ahvaz.Materials and methods: Biology of the pest species was evaluated at five laboratory constant temperatures 15, 20, 25, 30and 35±2°C (65±5% RH and a photoperiod of L: D 14: 10 h) on Chinese hibiscus leaves in plastic boxes (8×6×2 cm). Number ofM. hirsutus generations was also studied in clip cages on hibiscus shrubs in Ahvaz urban landscapes within a year. Population fluctuations of the insect were also investigated on those shrubs in two different regions of Ahvaz for 16 months. For this purpose, random sampling was done on five shrubs in each region bi-weekly. Eight twigs, 5 cm in length, were cut from the upper and lower halves of each shrub quadrant and a number of all mealybug developmental stages per twig were counted and recorded.Analysis of duration of different developmental stages was done by one-way ANOVA. For data analysis means were compared using SPSS 20 at 1% significance level. Data were assessed for normality by Shapiro-Wilkinson test in SPSS, and Anderson-Darling test in Minitab15 at 1% significance level.Results and Discussion: Total life span ofthe female ofmealybug from egg to death at 20, 25, 30 and 35±2oCwere 91.18±1.15, 51.68±0.84, 38.18±0.68 and 36.93±0.64 days, respectively. This period for a male was 60.69±1.57, 33.67±0.48, 24.33±0.57and 21.37±0.62days, respectively.No eggs were hatchedat 15°C. The longest and shortest life span of both male and female mealybugs wereat 20 and 35°C, respectively. No female could lay eggs without male and die after amonth. Therefore, matingwas necessary for egg production.However, there are reports of parthenogenetic reproduction in this pest species. An average number of crawlers produced by each female at above mentioned temperatureswere 152.2±6.25, 268.8±7.82, 322.2±6.18 and 240.3±11.86, respectively. The pest produced seven generations on hibiscus shrubs according to clip cage results in Ahvaz the urban area.The average total pre-oviposition period from egg to adult in clip cages in urban area of Ahvaz were 38.67, 34.04, 35.40, 45.21, 39.59 and 67.75 days for 1-6 generations during a year, respectively. Study of the pest population fluctuations showed thatthis pest species overwintered as different developmental stages in crevices of shrub bark. The mealybugs which were hidden in crevices of shrub bark in winter started to occupy the new leaves and twigs in early April.Ants were walking in lines on twigs and around mealybugs in high numbers, indicating the importance of ants in transporting mealybugs from winter shelters to newly grown twigs and leaves in early spring.The moderate temperature in autumn helped the population built up of the pest. Some differencesobservedbetween duration of developmental stages of the mealybug in our study and some previous studies may be arise from the difference in host plants and/or the origin of the studied populations. The 6th and 7th generations occurred in winter with very short developmental time.Conclusion: Because this pest has a potential for spreading through other Iranian provinces, combining the present results with the previousstudieson this mealybug and its natural enemies’interactions in Khuzestan, mayprovide a perspective for appropriate control of this pest in Iran.

Introduction: Fungal diseases are a major problem in the cultivation of grapevine, Powdery mildew disease caused by plant pathogenic fungus, Erysiphenecator is one of the most important and destructive diseases of grape in many countries of the world including Iran. Due to extend viticulture area in Iran and the high prevalence of the grape powdery mildew in vineyards, application of sulfur based fungicides is mainly recommended for the disease control. This study was conducted aimed to investigate the effect of new formulations fungicide of sulfur SC 80% and penconazole EW 20% to control grape powdery mildew disease.Material and Methods: The experiments were conducted on Askari cultivar as susceptible in Ardabil, KhorasanRazavi and Kohgiluye and Boyer-Ahmad provinces and in vineyards, which in previous years had a history of infected and trees were similar in age and growth conditions. Experiments were carried out in a completely randomized block design with four replications. Treatments were composed of penconazole EW 20% 0.125 ml L-1, sulfur SC 80% 2, 2.5 and 3 ml L-1 and control. The spray was carried out three times, including when the young shoots were between15 and 35cm, before falling flowers and stage of sours. One week after the last spray sampling of leaves and clusters was carried out in four directions main canopy trees randomly in each plot. Efficacy of treatments was evaluated based on infection severity found in 60 leaves and 12 clusters in per plot. To determine the amount of sugar and tartaric acid in the grape fruit, sampling of the healthy and infected clusters were carried out and healthy and infected the samples were then separated into a plastic bag and crushed.Then, the juice wasprepared (fruit juice was obtained from 700 g fruit in each sample).To determine the amount of sugar, hand-held refractometer was used and the amount of sugar was determined in healthy and infected fruit.For the determination of tartaric acid in grape juice titration using sodium hydroxide, 1.0 M was carried out.To determine the yield of grapes per healthy and infected plants and determination of the quantity of the yield damage caused by the disease, after fruit ripening, all clusters of grapes were picked by hand and weighed. Then in each province data were transformed and statistical analysis of data using SAS software was carried out. The mean comparisons were conducted with Duncan's Multiple Range test and Fisher's Least Significant Difference (LSD) test at the 5% level.Results and Discussion: Combined analysis of variance studied traits showed that between locations in terms of severity of disease in leaves and fruits, between treatment and locations and treatment interaction in terms of severity of disease in leaves and fruits, yield there was the significant difference. Analysis of variance amounts of sugar and acid concentration in the grapes in Ardabil (Meshginshahar) showed between treatments in terms of the amount of sugar and acid concentration in grape was observed the significant difference. According to the results sulfur SC 80% fungicide at concentrations of 2.5 and 3 per thousand the greatest effect in reducing the powdery mildew disease and increase yield and quality of grapes. Analysis of variance for amounts of sugar and acid levels in the grapes in Ardabil (Meshginshahar) showed highly significant differences among treatments in grape sugar and acid concentration at 1% level. Comparison of means indicated that control treatment (without spraying) had the highest concentration of sugar and acid. In this study, increasing the severity of thedisease on the leaves and fruit tended to increased acid concentration in the fruit. In this study, the yield of the grape was decreased depending on the disease severity on the leaves and clusters. In this experiment, increasing the severity of the disease on the leaves and fruit tended to increased sugar amount. The intensity of infection was higher in the leaves and fruits as well as the amount of sugar in sugar increases that were consistent with findings of another researcher.Conclusions: According to the results and taking into consideration environmental protection, the lowest intensity of infection in the leaves and fruit, the highest yield, the most normal sugar and acid concentration were on the treated plants with the sulfur concentration of 2.5 per thousand. According to the results of this study, spraying sulfur SC 80% in the control programs of the disease to prevent the emergence of resistant races of grape powdery mildew would be desirable.

Introduction: The subterranean termites make large damage to wood and cellulosic products. They can have the destroying effects on forest plantations, agriculture crop, and urban landscaping. According to the previous studies, Microcerotermesgabrielis Weidner is the most important termite of the Alborz province belong to the family Termitidae. This species is also reported in the central, the northeastern and the southern regions of Iran.MicrocerotermesvaraminicaGhayourfar, Amitermesvilis (Hagen), A. kharazii Ghayourfar, Anacantthotermesvagan(Hagan) have been also reported from Tehran province.Chemical control of termiteis the most conventional method ofcontrol. A few insecticides have acceptable termiticide effects. However more of them have negative effects on the other non-targets organisms in the environment, and may run off into groundwater. Thus we wouldconsiderthe other methods of termite control. Usage of native and natural resistant plant species can be reasonable strategy against termitesinafforestation. Plant species are food sources for termites, however, they differ in their palatabilityand can affect termite preference. There are some studies have reported differences in feeding rates and preferences of termite species amongdifferent species of woody plants.Tree Shalamzar Plantation, encompassing 54 ha in the southern Alborz mountain range have sustained termite damage since 2013. The objective of this study was to evaluate the natural resistance of eight different sapling species to termite´s damage in this region.Materials and Methods: Termites were collected from four infested locations within Shalamzar Plantation, Karaj, Iran. Infested saplings with active termite tunnels were visited and soldier termites collected and transferred to the systematics lab for species identification using a systematic key of Iranian termites. Termite infestation rates were estimatedfor each of 8 sapling species. Ten saplings of each species were randomly selected and examined from the four infested locations. Termite-free saplings with no damage or mud tunnels were designated as healthy ' control' plants. Infestation rates were calculated based on the number of infested saplings per total number of each sapling species. The saplings were classified by the termite damage in five categories: 1. health (0% damage) 2. Low ((>0 to 25%) 3. Medium ((>25 to 50%), 4. High ((>50 to 75%) 5.Dead ((>75 to 100%). Data on percentage of infested saplings from each species were subjected to PROC GLM model in completely randomized design. Differences among means were analyzed using LSD Test (P ≤0.05).Termite damage was analyzed using the Kruskal–Wallis test. Mean termite damage rates and frequency of damage groups in each plant species were estimated.Results: The results showed that Microcerotermesgabrielis is only damaging termite species on the studied saplings in these regions. Juniper and mountain almond species had no termite infestation and were resistant to its attack. Silverberry and hackberry species were the most susceptible saplings to termite damage with a 65 and57.5 % infestation rate and 60.44 and55 % dead rate, respectively. Judas sapling plants had over 60% termite infestation rate, sustained 20% mortality. It is tolerant species to termite. Ash and barberry species hadless than 50% oftermite infestation and their dead plant rate was 35.42and 28.33 %, respectively. Thus, the species of juniper and mountain almond saplings can be replaced by dead saplings.Discussion: Microcerotermesgabrielis is the primary sapling-damaging pest on the southern Alborz mountain slopes. This is the first report of termite attacking saplings in Iran. Susceptibility of saplings to termite damage varies with termite species.Microcerotermes spp. prefers to feed Faqus sp., whereas Microtermes sp.feeds morePicea sp. and Odontotermes spp. feeds live plant tissue and tree bark. Hackberry and silverberrysaplings were preferred by M. gabrielis, whereas the species ofjuniper and mountain almond showed resistant totermite´s infestation. There are many factors affecting termite feeding preference. Wood moisture and densityaffect wood palatability to termite, and some plant chemicalssuch as phenol compoundsand lignin ofwood act as antifeedants and repellents on termite.Conclusion: The species of juniper and mountain almond saplings were the most resistant to M. gabrielis.Amongsaplings sustaining damage, Judas tree had also the lowest mortality. So, three species ofjuniper, mountain almond and Judas are recommended to be considered for tree planting in locations whereM. gabrielis has infested the soil. It is prudent to identify the predominant tree-damaging termite species in areas designated for afforestation, and determines the plants and trees that are the highest levels of resistant to damage by indigenous termites prior to conducting planting operations.

Introduction: Milky thistle (Silybum marianum) is an annual or biennial plant of the Asteraceae family.Possibly native near the coast of southeast England, it has been widely introduced outside its natural range, for example into North America, Iran, Australia and New Zealand where it is considered an invasive weed.Seed is an important stage of plant life history. Most invasive plants primarily rely on seedling recruitment for population establishment and persistence. The rapid spread of many invasive plants is frequently correlated with special seed traits. Seed trait variations exist not only among species but also within species. Seed traits variations within a species are essential for the seedling establishment at different habitats.Environmental factors, such as temperature, soil solution osmotic potential, solution pH, light quality, management practices and seed location in the soil seedbank, affect weed seed germination and emergence.Fluctuations in temperature can influence seed germination differently than those under constant temperatures; however, such information is not available on Milky thistle. A light requirement for germination is the principal means by which germination can be restricted to an area close to the soil surface, and species requiring light for germination are potentially more likely to be prevalent in no-till and pasture systems. Soil pH affects the development and competitiveness of crops and weeds by affecting the availability of essential minerals, nutrients, the solubility of toxic elements, and soil microflora. Seed burial depth (buried by tillage or other means) also affects germination and seedling emergence of several weed species.Better knowledge of the factors that influence seed germination and seedling emergence of Milky thistle could contribute to the development of control measures and help determine its potential for invasion into new areas. The objectives of this study, therefore, were to determine the effect of various environmental factors on seed germination and seedling emergence of Milky thistle.Material and Methods: Germination of Milky thistle was determined by placing 25 seed in a 9-cm-diam Petri dish containing two layers of Whatman No.1 filter paper and moistened with 5 ml of distilled water or a treatment solution.Temperature: Germination of freshly harvested seed was determined in growth chambers under fluctuating day/night temperatures (15/5, 20/10, 15/25, 15/30 and 20/35° C).Salinity: In this experiment, seeds were exposed to seven levels of increasing salinity using NaCl solutions including 0, 10, 20, 40, 80, 160 and 320 mM. Petri dishes were incubated as described in the general protocol under the light⁄dark regime.pH: To examine the effects of pH on seed germination, buffered solutions of pH 5 to 9 were prepared.Seed burial depth: The effect of different burial depths on seedling emergence was investigated in a growth chamber. Seeds were buried at six different depths (0, 0.5, 1, 2, 4, and 8 cm) in 15-cm-diam plastic pots.Statistical analysis: Data were subjected to two-way analysis of variance (ANOVA) and the difference between treatment means was separated using FLSD test. A significance level of 5% was applied by SAS 9.2.Results and Discussion: The results showed that effect of different temperature regimes on germination percentage and rate, plumule length and seedling dry weight were significant (P<0.01). Increasing temperature led to increasingin all the traits. Increasing salinity level decreased the studied traits significantly. Also, pH had a significant effect on germination characteristics of Milky thistle. The highest values of the traits were gained at 7 and 8 pH. The lowest value of the traits was assigned to 5 pH. Various seed burial depth had a significant effect on seedling emergence percentage. The maximum seedling emergence percentage was assigned to 0 and 1 cm seed burial depth. Seed burial depth of 1 cm showed the highest root length (19.5 cm).4 and 0 cm depths had thehighest and lowest stem length, respectively. Seed burial depth treatment had no significant effect on root weight, but shoot dry weight affected by burial depth, significantly. The highest shoot dry weight (0.62 g/plant) was gained at 4 cm burial depth.Conclusion: Results showed that the effect of different temperatures on maximum germination percentage and rate ofSilybummarinum were significant, as, the highest and lowest germination percentage wasobserved at 20/35 (night /day) with a 98.5%, and 5/15 (night /day) with a 38%. Increasing salinity reduces seed germination.Maximum seeds germination ofSilybummarinum was occurred at depths of 0 and 1 cm with 93.35 and 89.37 percent, respectively. General emergence decreased with increased seed burial depth. PH treatments had the significant effect on germination of this weed. Minimum and maximum germination ofSilybummarinum were gained at pH 5 and 8 with 21.5% and 96.5%, respectively.

Introduction: Quality of water used in spray tanks can affect herbicide efficacy, especially acidic herbicides such as 2, 4-D. Water is the primary carrier for herbicide applications and it usually makes up over 99% of the spray solution. Considering that, it should be no surprise that the chemistry of water added to the spray tank greatly impacts herbicide effectiveness. Some ions such as calcium and magnesium cations that dissolve into the water, creating various levels of hardness in the water supply.2, 4-D is weak acid herbicide that can be influenced by hard water cations or foliar fertilizers. It has shown reduced activity when applied in water containing calcium and magnesium cations. Hence considering the quality of the water tank sprayer especially hardness helps optimize the efficacy of herbicides. Thus this research was conducted to determine the effect of different salts to 2, 4-D on kochia and redroot pigweed as indicator weed species.Material and Methods: Greenhouse experiments were conducted during 2014 at Ferdowsi University of Mashhad to determine the effect of sodium bicarbonate, calcium carbonate, magnesium chloride and calcium chloride in 500 ppm and deionized water as the control on the efficacy of 2, 4-D in three doses including 135, 270 and 540 g. a.i. ha-1 (SL 72%) with and without ammonium sulfate (AMS) (2% w/v). Kochia and Redroot pigweed were planted after breaking dormancy in plastic pots. Herbicide was applied using a backpack sprayer calibrated to deliver 290 L ha−1 at 200 kPa with flat-fan nozzles (Tee Jet 8002 flat-fan spray nozzles). Spray solutions were thoroughly agitated each time a new solution was prepared and immediately prior to application to bring herbicide into solution. Living plants were recorded 3 weeks after herbicide treatment irrespective of the timing of application. In addition to survival, the above-ground dry weight of Kochia and redroot pigweed in each pot was determined 3 weeks after the optimum timing of herbicide application. The experimental design was a randomized complete block with 3 replications. Data were subjected to ANOVA for a factorial treatment arrangement using Minitab ver.17. Means of significant main effects and interactions were separated using Fisher’s Protected LSD test at p≤0.05.Results and Discussion: Results of ANOVA showed that all factors included 2, 4-D doses, type of salt and AMS application had significant effects on survival and dry matter of Kochia and redroot pigweed three weeks after treatment. In this experiment, 2, 4-D toxicity to Kochia and redroot pigweed was antagonized by salts available in the spray carrier. Reducing in 2, 4-D efficacy for Kochia control in the presence of salts such as calcium, magnesium and sodium by Nalewaja and Matysiak (1993b) was reported. In Kochia, sodium bicarbonate was more antagonistic than the others. But there is no difference between inhibitory effects of all salts in redroot pigweed. Muelleret al. (2006) reported that calcium and magnesium concentrations greater than 250 ppm antagonized glyphosate activity on the weeds such as broadleaf signalgrass, pitted morningglory, Palmer amaranth and yellow nutsedge. Nalewaja and Matysiak (1991) showed that the glyphosate toxicity to wheat was antagonized by sodium, calcium, and magnesium. In addition, results indicate that antagonism of salts on 2, 4-D efficacy can be overcome by AMS in both two species, Kochia and redroot pigweed. Shahverdiet al.(2009) showed that the activity of the weak acid herbicides such as glyphosate, chlopyralid, 2, 4-D increased with the addition of ammonium sulfate to the spray solution. Also, Roskampet al. (2013) showed that the activity of the 2, 4-D and dicamba increased with the addition of ammonium sulfate to the spray solution for control of redroot pigweed, grass horse and lambsquarter. Results of interaction effects between 2, 4-D dose and type of salt show that by increasing herbicide dose antagonism effects of cations were decreased. According to our results application of ammonium sulfate in on hard water increased the efficacy of 2, 4-D four times in Kochia and more than four times in redroot pigweed.Conclusion: The efficacy of 2, 4-D on Kochia and redroot pigweed was affected by salt type in the spray carrier. Type of salts was different between two species, in Kochia, sodium bicarbonate had more negative effects and in redroot pigweed each four salts had similar effects. Numerous studies have shown that cations can influence herbicide efficacy depending weed species. Also our results showed that control of Kochia and redroot pigweed increased when AMS was added to 2, 4-D in spray solutions. AMS has been considered important to herbicide enhancement or to overcoming herbicide antagonism by salts in spray carrier, AMS also enhance 2, 4-D phytotoxicity in the absence of antagonistic salts that this confirm previous reports. It was concluded that weed species responded differently to the inhibitory effects of different cations in spray solution and AMS application, thus making a simple recommendation for all conditions is difficult.

Introduction: Race 3/ biovar 2 of this pathogen causes bacterial blight of solanaceous plants especially potato in both tropical and temperate regions and results in great economic losses worldwide. Infection is prevented via quarantine or incineration of infected plant materials. However, the use of healthy seed tubers is the most effective way to avoid dissemination of this harmful plant pathogenic bacterium to pathogen-free areas.Amplification of functional genes such as endoglucanase andhrp B and fli Chas been used as an alternative to studyR. solanacearum species complex. In order to facilitate detection of R. solanacearum in imported seed tubers and identify high-risk fields and stores where inoculums population is low, loop-mediated isothermal amplification (LAMP) reaction as a potentially fast and cost-effective method was used. The attention of the present study wason evaluation of latent infection in potato tubers withR. solanacearum bacterium targeting the fliC gene by colorimetric LAMP assay. The LAMP protocol was compared with the conventional PCR which routinely used at most quarantine stops.Materials and Methods: In this study, bacterial strains were isolated on tetrazolium chloride (TZC) agar medium. Pathogenicity assay was carried out on tomato and potato seedlings under greenhouse conditions. Total DNA of bacterial strains was prepared using Chen and Kao (1993) protocol. In some cases, the boiled filtrated potato extract was used directly in molecular experiments. Identification ofR. solanacearum strains at species and phylotype levels and biovar determination were done based on literature. The PCR products were analyzed on 1.2 % agarose gels in TBE buffer and visualized with UV light. To detectR. solanacearum in symptomatic and symptomless tissues, conventional PCR and LAMP assay according tofli C gene were performed and compared with each other. In order to check amplified LAMP products in visual assessment, the existence of magnesium pyrophosphate precipitate in tested tubes was analyzed. Furthermore, change in colourdue to the reaction was evaluated bynaked eye and UV treatmentafter adding the calcein. Finally, the LAMP products were examined by electrophoresis through 2% agarose gel after staining with green viewer. To determine limit of the LAMP assay, seven dilution series (2×107 to 2×10 CFU/ml) were prepared and 2 μl of each dilution was used for LAMP.Results and Discussion: Bacterial colonies showed mucous and opaque appearance with red centre and whitish periphery on TZC agar medium were selected for further study.In plant bioassay two weeks after bacterial inoculation, different levels of wilting were observed on tomato and potato seedlings.The expected 281 and 372 bp PCR-amplified fragments was observed in all strains supporting species and phylotype identification, respectively. Moreover, utilization of carbon sources indicated that the strains were related to biovar 2.Furthermore, all strains from potato were screened using Ral-fli C and Rsol- fli C primers. A 400 bp PCR product specific toR. solanacearum was obtained from all strains. Sequencing three purified PCR products confirmed the right amplification offli C gene specific to R. solanacearum.The amplified products were detected by visual observation which the white turbidity of the reaction mixture by magnesium pyrophosphate was seen after 55 min. An alternative indicator to visually check the positive reactionwas calceinwhich was based onobservation ofyellow (green) in colour at the absence (presence) of UV light in infected samples and clear colour in negative control. Detection limits in pure cultures and infected potato extract were also determined. In conventionalfli C-PCR, the detection limit rangedapproximately from 10 3to 10 4cfu ml−1in both infected potato extract and pure cultures. Moreover, the lowest amount of consistently tested positive through LAMP assay was 104cfu ml−1 for both cases.Although the sensitivity of thefli C LAMP assay wasequal or lower than that of the conventional PCR, theaccuracy offliC LAMP seems to be sufficient toreliably confirmthe presence of R. solanacearum in potato samples. In addition, LAMP protocol assay is time-consuming procedure, does not require expensive equipments, provides visually detection of positive reactions and can apply to survey possible infection in host plants.Conclusion: Consequently, LAMP assay with ashort nucleic acid extraction step like as boiling treatment and efficient visualization processes such as calcein provide suitable preliminary data for screening of pathogen–free tubers prior to storage and during transportation.

Introduction: Since the first compilation of herbicide-resistant weeds in 1982, the number of reported herbicide-resistant species has increased significantly. Iudosulfuron-methyl-sodium+mesosulfuron-methyl+ mefenpyr diethyl, sulfosulfuron and tribenuron-methyl, acetolactate synthase (ALS) inhibiting herbicides, clodinafoppropargyl, aryloxyphenoxypropionate (ACCase) inhibiting herbicides and 2, 4-D+MCPA, synthetic auxcins herbicides are registered in Iran for post emergence control of broadleaf and some grass weeds in wheat (Triticumaestivum L.). In southwest Iran, Khouzestan province, the appearance of wild oat (Avenaludoviciana Durieu), littleseedcanarygrass (Phalaris minor Retz) and wild mustard (Sinapisarvensis L.) populations with different degrees of resistance to mentioned herbicides has been reported previously in last decade. A reliable seedling bioassay was developed and tested for the rapid screening for resistance to aryloxyphenoxypropionic (APP) herbicides in some.populationsspecialy grass weed. This paper describes a rapid and reliable seedling test to detect APP-resistantA. ludoviciana, Phalaris minor and Sinapisarvensisbiotypes in order to determine their frequency within a population. This test has also been developed in order to discriminate between APP, ALS and synthetic auxcin -resistant biotypes.

Introduction: Canola is one of the important oil crops in Iran and blackleg disease caused by Leptosphaeriamaculansis an economically important disease of rapeseed especially in the northern provinces of Iran. At the beginning of the season in early autumn, L. maculans areinitiatesby air-borne ascospores released from infected stubbles of previous crops. These ascospores germinate and produce leaf lesions. The fungus then grows systemically from the leaf lesions to stem where cankers are produced which can result in major yield loss.Blacklegiscaused by a complex of at least two species of Leptosphaeria: L. maculans and L. biglobosa. Of these two species which L. maculans wasis much more prevalent and virulent than L. biglobosa and was reported from almost all oilseed rape growing regions of the world.A number ofmethods has been developed to differentiate isolates of these two groupsthrough morphological, physiological, genetic and molecular markers. Among these virulence markers of group pathogenicity are most widely used for characterizing the pathogen population. The purpose of this research work was to investigate isolates identification based on colony morphology and molecular methods. Moreover, for management strategies to be effectiveit is important to recognize the population structure based on pathogenicity groups and an understanding of possible shift in fungus population in thenorth of Iran.Materials and Methods: Infected plants of oilseed rape were collected from the northeast Iranduring 2013-2016. Diseased plant organs with clearly defined symptoms of the disease were used for the isolation of the fungi. All isolates were analyzed using a combination of morphological and physiological. In order to confirm the identification ofL. maculans from oilseed rape isolates, DNA was prepared using the standard method described previously. The ITS region of genome of all isolates was amplified using polymerase chain reaction with specific primers pair LmF, lmR. Some isolates were sequenced with ITS1 and ITS2 along with the 5.8S rRNAregion and then sequence data were compared with that of availableL. maculans isolates in Gene Bank.Aggressive isolates ofL. maculans collected in widely separated geographic regions were further divided into pathogenicity groups based on virulence of three differentBrassica napus cultivars.Results and Discussion: Morphological and physiological and molecular characterizations of 72 isolates were performed. Isolates grewslowly, the pycnidia of the fungus were black, globose to subglobose in shape and conidia were single-celled, hyaline. The most of isolates formed yellow and pigment formation was scored in six groups in PDB at 18°C in the dark on the shaker. The PCR detection showed that all isolates were amplified by L. maculans-specific primer pair and a 334-bp PCR product was reliably amplified from L. maculans. The sequence analysis of the ITS region revealed that the sequences had 99.7% sequence similarity with the ITS sequences of knownL. maculans isolates in GenBank by NCBI Blast search. This isolates were registered with accession number KX649997 and KX792142 in gene bank and this confirmed that the pathogen exists in Brassica napussamples. The role of morphological identification in virulence is complex and the production of pigment and mycelial growth is not always correlated with virulence. Therefore, based on amplification with type specific primers the amplified product fragment specific for group A was found in all isolates. It is important to know which pathotype is present, because the pathotypes ofL. maculans differ in the amount of damage they cause. Based on the reaction of isolates on differential cultivars all four group pathogenicity PG-2, PG-3, PG-4 and PGT were observed in aggressive isolates. The most isolates were classified to be a pathogenicity PG-4 virulent on three differentcultivars and for the first time wasidentified in Iran.Conclusions: In order to determine whether isolates belonging to the canker L. maculans are present in the north of Iran, initial species identification based on colony morphology was confirmed using molecular methods.Asthe pathogen causes considerable losses, thefast identification and pathotype determination are important foragriculture and successful management of blackleg disease. Our results showed that an understanding of possible shift in fungus populations of PG2 to PG4 will be of value in developing strategies for successful management of blackleg disease.

Introduction: Potato (Solanumtuberosum) is one of the most important crops used as a source of human food. Iran is the third-largest producer of potato in Asia, where the production rate in 2015 was estimated to be about 5 million tonnes. Potato producers inHamedan province produce 21.3% oftotal potato harvestedinIran.Golden potato cyst nematode, Globoderarostochiensis is the most destructive potato pathogen. As the chitin is a dominant composition in middle layer of the eggshell, using the chitinases produced as chitin-degrading enzymes in a wide range of fungiis a good strategy for biological control of the golden potato cyst nematode. We assessedthe ability of various antagonistic fungi to controlGloboderarostochiensis under in vitro and greenhouse conditions.Materials and Methods: Thirty four fungal isolates obtained from infected eggs of the potato cyst nematode, Globoderarostochiensis in potato fieldsofHamedan were evaluated in two chitin-agar and water-agar mediums under in vitro and greenhouse conditions.The ability of thechitinase enzyme production was assessedin chitin-agar medium with colloidal chitin as substrate, so the chitin was used as exclusive source of carbon.Colloidal chitin was prepared based onthe procedure of Seyedasliet al. (2004) with 10 g of powder chitin from practical-grade crab shell chitin (Sigma) in 100 ml of 85% H3PO4. Water was added to the above mixtureand was filtered with cheese cloth. To completely remove acid, water addition and filtrationrepeated for several times. The produced unguent materialwas dried and powdered and then used as carbon source in the medium.0.5 percent of colloidal chitin was added to the medium. Afterwards, a 5 mm disk from the edges of 5days old was placed in the center of Petridish and all of them were kept for 5 days at 25º C. Chitinase detection medium (chitin-agar) was directly supplemented with colloidal chitin (5 g/l) and bromocresol purple (0.15 g/l).The ability of antagonistic activity of the fungi on the cyst nematode was testedin water-agar medium through assessing the interaction between fungi and cysts. The numbers of healthy and parasitized (dead) larvae and eggs were calculated after two weeks. The ability of the antagonistic fungi under greenhouse conditions was also analyzed. To provide fungal inoculum, 20g of soaked wheat seed were cast in nylon with autoclave capability.2 ml distilled water were added per gram of cast seed and they were autoclaved threetimesduring 24 hours. Four fungi disk with 5 mm diameter from selected isolates were then added to allnylonswiththreerepetitions and werekept in 25ºC and dark conditions. To colonizeall of the seeds and avoid hangingthem, the seeds in nylons were mixed within 48 hours interval. After three weeks all of the seeds were infected with fungal isolates. The ability of the antagonistic fungi under greenhouse conditions was studiedby adding fungal inoculum and 100 cysts to each pot and performance evaluation of potato traits in pot after 90 days.ANOVA (Analysis of variance) data analysis was conducted using of the SAS software version 9.0 in completely randomized design (CRD) with three replicates under all conditions.Results and Discussion: The ANOVA results ofqualitative evaluation for chitinase activity in Petri dish containing chitin-agar showed significant difference among isolates at1% level of significance. Furthermore, there was apositiveassociationbetween diameter and chitanase activity. Isolates 153 (P. lilacinus) and 6 (C. parapsilosis) had the maximum and minimumdiameter, respectively.A significant difference was foundamong isolatesin the 0.1% level of significance. Isolate 152 (L.muscarium) had the greatestantagonistic ability and 62 (F. solani) was the weakest antagonist isolate.Mean comparisons of measured performance traits of potato in pot showed in all traits thatisolates 154 (T. atroviridae) and 151 (B. bassiana) were the best antagonist isolates under greenhouse conditions. Isolates56 (F. equiseti) and 12 (F. oxysporum) with the lowest measured values in all functional traits were alsothe weakest antagonist fungi.Conclusions: The results illustrated a strong correlation between antagonistic ability of fungal isolates under in vitro and greenhouse conditions.Therefore, fungal isolates can effectively reduce the nematode damages.Finally, isolates 151 (B. bassiana), 152 (L. muscarium), 153 (P. lilacinus) and 154 (T. atroviridae) were selected as the strongest antagonistic fungi in controlling this nematode.

Introduction: Summer annual weeds typically germinate in spring and early summer, grow throughout the summer, and set seeds by fall. Summer annual weeds are a persistent problem in summer annual row crops, competing directly for water, light, and nutrients, causing yield losses in quantity and quality.Although agriculture is increasingly relying on modern technology, knowledge of the biological systems in which these technologies are used is still critical for implementation of management strategies. Biological information about weeds is valuable and necessary for developing management strategies to minimize their impact. Scouting fields for pest problems are essential in any cropping system and knowledge of the timing and sequence of weed species emergence could increase the effectiveness of weed scouting trips and subsequent management practices.

Introduction: The spider mite, Oligonychus afrasiaticus feeds by sucking the sap from the immature fruits tissue. The natural color of fruits changes to pale yellow or gray by mite's feeding. Damaged fruit are cracked and its damage can dry out the fruits. Because of resistance to pesticides, resurgence of date palm spider mite causes to disrupt the natural balance of their population. Tiny black ladybird beetle, Stethorous gilvifrons is the most important and active lady beetle species in Khuzestan province and is very effective on biological control of the spider mite. Determination of the amount and release time of the lady beetles are the most important factors in the implementation of biological control programs of date palm spider mite. So, careful monitoring, time of the release and the ability of deployment of predatory ladybird are essential steps to success in the programs of biological control.Materials and Methods: This research was conducted in Shadegan region of Khuzestan province. The nested design was used to compare the efficiency of different inoculate release methods of the predator, S.gilvifrons. The main niches include three release times which were at the time of emergence, three days and one week after emergence of date palm spider mite in date palm plantation. Sub nesting including three different levels of predator release including minimum, moderate and maximum release with 0.5, 1 and 3 predator /m2 per day and were continued for two weeks. The two or three-days ladybirds were used to release. First, the infected clusters were covered by mesh fabric and ladybirds were released under them. After a week, mantles were opened up to the establishment of ladybird run on the normal condition of date palm plantations. This experiment was repeated three times, and each replication consists of a quarter- hectare plantation with dominant cultivar Sayer. Three date Palm trees from each release and control were randomly selected. One hundred fruits from10 major's of each bunches were randomly selected and the number of spider mite (prey) and coccinellid (predator) were counted in different developmental stages. The relationship between predator and prey was calculated by using Pearson's correlation in different treatments as an index of density-dependent reaction of the predator to prey density and its establishment.Results and Discussion: Results showed that there were significant difference between treatments of release on seasonal mite and lady beetle populations and the average seasonal growth reduction rate at 1% probability level. The maximum difference in the number of mite – infested treatment and control occurred at maximum release with predatory mite. The maximum density of the lady beetle population was observed around mid to late June. Date palm fruits were been at Kharg phonological growth at this time and they had the greatest sensitivity to the mite population. The highest correlation coefficient occurred in terms of release time coincided with the moderate and maximum release of spider mite´s predator. So, the predator showed density - depend reaction and its establishment were occurred. Release of three and one lady beetle/m2 and simultaneously with the appearance of spider mite had powerful and significant correlation. In those circumstances, the density-dependent response of lady beetle was observed. The prey and the predator population densities have several fluctuations around their equilibrium level during the season. Number of predator population declines and prey population increases from their equilibrium levels were reduced by the simultaneous release of the predator to start prey activities.The predatory failure establishment is zero in the maximum release.The highest control of date palm spider mite was about 83.28% at release treatments. In all releasing treatments, the level of biological control was increased with increasing the number of coccinelid releases per unit.Conclusions: The highest predator efficiency were calculated in the maximum release (3 coccinellid persquare meter) and simultaneously with the appearance of spider mite in date palm plantation. The control performance was 83.27 percent in this condition. Understanding of the fluctuations of the date palm pests and their natural enemies and the effect of climatic factors on the fluctuations are necessary to operate the proposed models for biological date palm pest control. The success of this predator is high in terms of the date ecosystem, and the susceptibility of palm fruit to pests decreased at the end of the season.

Introduction: Cabbage aphid (Brevicorynebrassicae L.) is one of the most important pests of canola in Iran.The pest attacks to the leaves, stems, flowers and pods of the host plant. Feeding and sucking the sap from the plant tissues normally cause leaf and stem deformities and reduce the quality and quantity of the seeds. It was reported that damage caused by the pest can reduce 9 to 77% of the canola yield. Several studies indicated that host plant resistance is an important method which influences population dynamics ofB. brassicae and reduces damage of the pest in the field conditions.Using resistant varieties can be the simplest, practical, effective and economical method for the pest control ascomparedwith other control methods. The aim of this investigation was to study population dynamics of the cabbage aphid on different canola cultivars under the natural field infestation and evaluate thepest influence on the studied cultivars/hybrids yield and yield components in Shahrekord.Material and Methods: Population dynamics and damage of cabbage aphid were studied on five cultivars (including: Okapi, Licord, Talaye, Modena, Tasilo) and two hybrids (Hyola 308 and Hyola 401) of canola based on the completely randomized block design in three replicates under the field conditions. To study population dynamics of the pest, sampling was started from the beginning of the infestation (the first decade of April) and continued weekly until harvesting time. For this purpose, five plants in each replicates were selected randomly and the number of aphids (nymphs and adults) was counted on 10 cm of each stem. Moreover, at the harvesting time, 10 plants from each replicate were selected randomly and the yield and yield components includingnumber of pods, number of seed per pods, weight of 1000 seeds were measured. Statistical analysis was done using Proc ANOVA in SAS 9.1 software.Results and Discussion: Ourstudy addressed the seasonal activity and population dynamics of the canola aphid on different canola varieties under the field conditions.The results indicated that the activity of cabbage aphidwas started from the first decade of April and reached to the highest level at the flowering stage at the third decade of May. The highest (450 aphids/plant) and lowest (200 aphids/plant) population density were observed on Talaye cultivar and Hyola 401 hybrid, respectively. Similar results were reported by KhazduziNejadJamali et al. (2012) and Sarwar et al (2002).Mean comparison of yield and yield components in different canola cultivars and hybrids under the field infestation to cabbage aphid showed the highest (83.47) and lowest (12.69) number of pods in Hyola308 hybrid and Modena cultivar, respectively. Moreover, the highest (13.27) number of seeds per pod was observed in Tasilo cultivars, whereasthe highest seed weight was identifiedin Tasilo and Hyola hybrids. Themaximum and minimumyieldwere, respectively, recorded forTasilocultivar (0.41 gr/plant) and Modenacultivar (0.01 gr/plant).Our finding was similar to the results of Monfared et al (2003) who reported that Hyola 308 and Hyola 401 hybrids and Talaye and Licord varieties were resistant to the cabbage aphid.Keyhanian et al (2008) observed the highest pest population on Licord cultivar which supports our findings.However, they reported the lowest yield in Hyola401 which is in contrast with our results. The differences between the results canbe due to the influence of environmental factors on the studied cultivars.Conclusion: Our results demonstrated that Hyola 401 hybrid had the highest number of pods per plantand number of seed per pod and Tasilo cultivar had the highest yield and seed weight. In addition, the lowest yield and yield components was found for Modena cultivar. Therefore, Tasilo was the most suitable and Modena was the least suitable cultivar for growingin Shahre-kord.Sincepesticide applicationto control the pest has several disadvantages such as increasing production cost, developing resistant races, destroying natural enemies and environmental hazards, integrated pest management based on the host plant resistance is, therefore, essential forcontrolling the canola aphid. Usingthe resistant hybrids and cultivars can reduce insecticides hazards, protect natural enemies and help integrated management of the canola aphid.

Introduction: An adjuvant has been defined as ‘a material that when added to a spray solution improves or modifies the performance of an herbicide’. There are five categories of adjuvants including drift retardants, extenders, stickers, wetters, and penetrants. The latter can chemically be divided into mineral or vegetable groups. Although some reports have found that vegetable oils are less effective than mineral oils, in view of the environmental concerns, the use of vegetable oils seem to be a suitable alternative to mineral oils because they offer a series of advantages such as being biodegradable and renewable resources. The plants essential oils are extracted from the medicinal plants not only have an adjuvancy activity at low concentrations but also have an herbicidal activity at high concentrations. It is believed that the benefit of vegetable oils as adjuvant can be related to their ability (i) to increase the drying period of the spray droplets during their fly time before impacting the leaves, (ii) to prevent bouncing off after impacting the leaves, (iii) to decrease contact angle of the droplet on the leaf surface and improve the spreading of them on the leaf surface, (iv) to delay crystallization of the active ingredient on the leaf surface, (v) to reduce the volatizing and photo-decomposing period of the herbicide active ingredient, (vi) to act as a penetrant agent on the leaf epicuticular wax in order to enhance the penetrability of the herbicide active ingredient into the plants. A fundamental part of all agrochemical researches is search to detect the natural chemicals offering adjuvancy properties to enhance the biological activity of agrochemicals.Therefore, we conducted a dose-response experiment to determine the potential influence of Blackseed, Fennel, Olibanum, and Rose oils as oily based-adjuvants in enhancing the imazethapyr activity against jimsonweed.Materials and Methods: The jimsonweed seeds were collected from plants in the fields of Qazvin and were stored in the dark at room temperature until further use. Bioassays were conducted in a greenhouse located on the Ferdowsi University of Mashhad, Iran. The seeds were washed every 1 h for 7 days for a total of 168 washings to remove seed germination inhibitors according to Andersen. They were sterilized with 5% (v/v) sodium hypochlorite solution for 10 min and rinsed with distillated water twice. Then, 25 jimsonweed seeds were sown in 2 L plastic pots filled with a mixture of sand, clay loam soil, and peat (1: 1: 1). The pots were irrigated three times a week. At the 1- and 2-leaf stage, the seedlings were thinned to 4 plants pot-1 and fertilized twice with 20 mL of a N: P: K (20: 20: 20) fertilizer with a concentration of 3% (w/v). The pots were irrigated every three days with tap water. Treatments were sprayed at the 4-leaf stage. Experimental design was a factorial arrangement with the 5 doses of imazethapyr (Pursuit® 10% SL) and the four essential oils at concentrations of 0.5 and 1% (v/v) in a completely randomized design with four replications. The emulsifier alkylarylpolyglycol ether was used to emulsify the substances in spray solution (95% oil+5% emulsifier). Treatments were applied at 180 L ha-1 at 200 kPa using a calibrated moving boom sprayer with an 8002 flat-fan nozzle. Three weeks after spraying, biomass from each pot was collected and then weighted after oven-drying at 75°C for 48 h. The data were subjected to a non-linear regression analysis using the following logarithmic logistic dose-response model described. The relative potency that is the horizontal displacement between the two curves was calculated by the ratio of doses producing the same response.Results and Discussion: The slope of dose-response curves for jimsonweed to imazethapyr without or with each adjuvant were significantly similar as indicated by the same slope (b), so that they could be considered to be parallel. This indicates that the adjuvants were biologically inactive if they are used alone (without herbicide) at the tested concentration. Based on shoot fresh and dry weights of jimsonweed, the values of ED10 (6.47 and 7.50 g a.i. ha-1), ED50 (18.08 and 19.01 g a.i. ha-1), and ED90 (50.48 and 43.54 g a.i. ha-1) were obtained. All these values decreased in the presence of all the adjuvants. The relative potency values were significantly different from 1, indicating a significant enhancement in the imazethapyr activity when the adjuvants were added to the spray solution. Based on fresh weight of jimsonweed, the imazethapyr activity was improved up to 4.61-fold with addition of Fennel oil at 1% (v/v). Nonetheless, based on fresh weight of jimsonweed, it was improved up to 4.50-fold with addition of Olibanum at 1% (v/v). Based on dry weight of jimsonweed, the adjuvants were ranked according to their performance in improving imazethapyr activity as follows: Fennel>Olibanum>Blackseed> Rose when they were applied at 0.5% (v/v). But, at 1% (v/v), they were ranked as follows: Olibanum>Blackseed>Rose>Fennel. There are no reports available about the effect of the tested adjuvants as an adjuvant for herbicide, but similar studies were reported by Cabanne who found that the clodinafop-propargyl activity was enhanced up to 5- to 6-fold with adding pine essential oil (Pinus pinaster Ait.) to spray solution at 0.5% (v/v).Vegetable oils have also been found to be effective adjuvants for several post-emergence herbicides. Only in case of Blackseed oil, increasing the concentration had a significant effect to enhance the imazethapyr activity as compared to others. The benefit of concentration effect has formerly observed by researchers who reported that there was a strong concentration effect for rapeseed oil since their influence on phenmedipham and glyphosate uptake and activity was lower at 0.1% than at 1% (v/v).Conclusion: Since the main barrier for diffusing a hydrophilic herbicide such as imazethapyr into the leaf tissue is hydrophobic cuticle, thus oil based-adjuvants have been known to work best with them. On the other hand, a shift from non-environmentally friendly adjuvants to environmentally friendly (namely from mineral oilbased adjuvants to vegetable oil-based adjuvants) in adjuvant trend has been occurred due to being biodegradable and renewable. Thus, it is necessary to look for new essential oils offering adjuvancy properties to improve the efficacy of such foliar-applied herbicides because it is a straightforward approach to reduce the risk of adverse side-effects of herbicide via reducing herbicide dose needed to control suitable weeds. From the present study, it could be concluded that the oils Blackseed, Fennel, Olibanum, and Rose showed a strong adjuvancy properties for imazethapyr against jimsonweed and hence they could be suitable for developing and testing as an oily based-adjuvant. Though it is questioned whether crop selectivity could be threatened when these adjuvants are applied, further work is required under field conditions to answer this question.