nematode

Cucumber (Cucumis sativus L.) holds significant agricultural importance in Iran, occupying extensive cultivation areas. Greenhouse conditions favor the proliferation of numerous pests and diseases affecting cucumber growth. Root-knot nematodes inflict yearly damage on cucumber farmers and producers, particularly in tropical and subtropical regions. Cucumbers are susceptible to various plant-parasitic nematodes, with Meloidogyne species, notably root-knot nematodes, posing significant threats. Controlling the nematode is challenging due to its wide host range, short life cycle, high reproductive rate, and parasitism. While chemical control remains prevalent for nematode population management, growing public concern over the environmental and human health impacts of nematicides is driving efforts to restrict their usage. Employing resistant varieties either independently or in conjunction with other strategies is increasingly recognized as a highly effective means of nematode control. Resistant plants prevent the need for long-term rotations and are highly suitable for sustainable agriculture. Consequently, the development of new cucumber varieties and hybrids and the assessment of their resistance can be applied in integrated nematode management. Hence, this research aims to evaluate the resistance of cucumber hybrids to root-knot nematodes (M. incognita) under greenhouse conditions.

Soil and root sampling was undertaken from cucumber cultivation sites in Guilan province. Egg masses were then introduced to the root systems of tomato seedlings, specifically the Early Urbana variety, at the two to four true leaf stage. Subsequently, these seedlings were nurtured for 45 to 60 days under greenhouse conditions. Identification involved the analysis of perineal patterns alongside morphological and morphometric traits of second-stage juveniles. Staining of female nematodes in root tissue was accomplished using the Hartman and Sasser method. Multiple consecutive inoculation cycles were executed on susceptible tomato plants to cultivate a substantial and uncontaminated nematode population. Seed germination took place in Petri dishes, with transfer to individual pots containing a mix of perlite and coco peat in equal measures after 48 hours. These pots were then randomly distributed within the greenhouse, with subsequent maintenance performed as required. The experiment followed a completely randomized design with three replications. Ten weeks post-inoculation, nematode-related parameters, such as the count of galls and egg masses using the Taylor and Sasser method, alongside the number of second-stage juveniles in the soil using the Barker method, were assessed. Subsequently, statistical analysis was carried out utilizing SAS 9.0 software following data normalization. Mean comparisons were conducted using the Tukey test.

The results showed significant differences in some traits of the hybrids treated with nematodes. Variance analysis revealed no significant differences in specific indicators, including gall count, egg sacs, eggs, second-stage juveniles in the soil, reproduction factor, as well as fresh and dry shoot and root weights across the assessed hybrids. However, significant differences were observed among the growth indices of plants, particularly in fresh and dry shoot weight, fresh root weight, and root volume. The mean weight of the aerial parts in the control was 103.66 g. Hybrid 5×3 exhibited the highest reduction, with a weight of 63.33 g, reflecting a 38.9% decrease compared to the control. Conversely, hybrid 7×6 showed the least disparity, with a weight of 100 g and only a 3.53% reduction. Notably, significant differences were evident in gall index, egg mass index, resistance index, root dry weight, and root length. According to the Taylor and Sasser ranking for determining gall and egg masses indices, hybrid 2×6 exhibited sensitivity, while the remaining hybrids were classified as very sensitive. Regarding the egg masses index, hybrids 5×3, 2×6, and 3×4 displayed relative resistance, whereas the other hybrids were categorized as sensitive. Evaluation based on the reproduction factor and gall index indicated that all hybrids were classified as sensitive.

The study concluded that none of the hybrids exhibited significant resistance indices. However, hybrid 2×6 demonstrated statistical significance in gall index, egg masses, and resistance, while hybrid 2×7 displayed superiority over the control variety in terms of larval count, egg count, and dry shoot weight. Consequently, pending further complementary experiments, these hybrids may be regarded as promising replacement candidates.

The genus Pseudoaulolaimus Imamura, 1931 along with the genus Aulolaimus are placed in the family Aulolaimidae Jairajpuri & Hooper, 1968, suborder Leptolaimina and order Areolaimida. Pseudoaulolaimus anchilocaudatus Imamura, 1931, is the only species in this genus, which was for the first time described by Imamura (1931) from a rice field in Japan. This species and the genus as well are mainly characterized by an anchor-like (fork-shaped) end of the tail in both males and females, which is a unique feature among all the known free-living members of the phylum Nematoda. The type material of this species was lost during World War II. However, more than 50 years after its first description, Sturhan and Lorenzen (1982) collected and reported P. anchilocaudatus from several localities in Germany and the Netherlands and provided a detailed redescription of the species based on the European type materials. This species has also been reported from Vietnam (Sturhan 2005) and Hungary (Andraasy 1997). In a survey conducted to study nematodes of Pir Naim village, Savadkuh County, Mazandaran province, North of Iran, a population including four females and eight males were extracted from soil of a rice field using tray method during 2020. After preparing the microscopic slides, their morphological and morphometric characteristics were examined and the obtained data of the population fit well to the original description; so, the population was identified as P. anchilocaudatus.

Jabbari H, Niknam G, Fallahi A (2023) First report of Proleptonchus brevisaccus (Nematoda: Leptonchida) from Iran. Plant Pathology Science 12(2):86-94.
Abstract: Nematodes are vermiform, with wide host range and geographical distribution, diverse and species-rich multicellular animals, which form a separate phylum in the kingdom of animals with the ability of living and surviving in all habitats. In order to identification of nematodes fauna of Astara- Mishe Sui forest – Gilan province, Iran, several soil samples were collected from sandy areas around a local river during 2014. The nematodes were extracted from samples by usual methods of nematology and after killing and fixing the nematodes were transferred to pure glycerin. Permanent microscopic slides of the nematodes were prepared and their morphological and morphometric characteristics examined using an optical microscope. Among the different feeding groups of nematodes, a population of the family Leptonchidae and the genus Proleptonchus was also obtained. The main character of the genus is having a flask-shaped cheilostome. Using valid references and identification keys, the population was identified as P. brevisaccus. This species belongs to the members of the genus that have short post vulval sac. Based on available literature, P. brevisaccus is a new record for the nematode fauna of Iran and its male is reported and described for the first time.

One of the most effective ways to preserve biodiversity is to convert conventional systems into organic ones. The organic farming system reduces the negative effects of intensive management. The biomass of the soil ecosystem has different responses in management methods including tillage, fertilizer and defense inputs, and organic modifiers. Understanding the role and responses of biomass in different cropping systems is essential to support sustainable horticultural practices in managing plant-parasitic nematode.

Sampling has been done from two organic farming systems, conventional and pasture, in order to identify the morphology of soil plant parasitic nematodes, soil physicochemical characteristics, and microbial respiration. Plant parasitic nematodes were extracted, killed, fixed, and transferred to glycerin and permanent slides were prepared. The effect of the type of cultivation system on the abundance and diversity of plant parasitic nematodes in common and organic apple and peach orchards compared to pasture were investigated by multivariate analysis of variance (MANOVA) in Xlastat 2020 software.

20 Genera belonging to 11 families of plant-parasitic nematodes were identified, which had different frequencies based on the type of cropping systems and crops. The comparison of the type of organic cultivation system with the common showed that it had a significant effect on the frequency and diversity of plant parasitic nematodes; the highest frequency of the nematode genus in organic peach cultivation system is Gracilacus and the lowest frequency is Scutylenchus genus in common apple cultivation. The abundance of nematode family in organic system is more than common and the abundance of nematode family in peach organic system is more than apple organic system. It should be mentioned that the common apple system is close to pasture in terms of abundance. The abundance of nematode family in the common system of peach is more than the common system of apple. The type of cultivation system had a significant effect on the frequency and diversity of Pratylenchus, Helicotylenchus, Tylenchus, and Rotylenchus genera, while it did not have a significant effect on the  Gracilacus genus. Type of host plant had a significant effect on the frequency and diversity of plant parasitic nematodes definitely in all soil condition variables. The type of host plant was significant on the frequency of all plant nematodes except Tylenchus and a significant effect on the diversity of all except Tylenchus and Rotylenchus. Among all soil factors, microbial respiration, EC, OC, K, P, and texture (percentage of soil particles including sand, silt, and clay) showed a significant effect on all lineages of nematodes.

Significant differences in community structure in plant parasitic nematode communities in three systems were recorded. The results of the present study have shown that the frequency and diversity nematodes are different from the results of other researchers in apple and peach orchards, that plant types and cultivars, basic genotype, or soil management practices affect the composition of plant parasitic nematode community groups. In this study, the abundance and diversity of nematode in the organic system was more than in pasture, and conventional agriculture with more than 10 years of history, including tillage and chemical inputs, and organic matter loss, erosion, and low in the soil agroecosystem. The reduction of the plant parasitic nematode in the conventional system compared to the organic system is caused by the reduction of organic matter, tillage, or chemical inputs. The results showed that the type of product and management practices affect nematode communities. The composition of soil nematode communities is significantly different in organic, conventional, and pasture farming systems. The organic peach and apple system is facing an increase in nematodes more than conventional. It seems that plant parasitic nematodes are sensitive to soil management practices. Soil nematodes are useful indicators to evaluate the intensity of management and sustainable management of horticultural ecosystems on soil ecosystem performance; because they have several feeding habits in soil, and micronutrient networks and play an important role in the food cycle, pest suppression, and regulation of microbial communities. There were high pest pressure of nematodes in the organic peach farming system in comparison to the apple farming system. In this research, apple is better than the peach for organic production in Damavand orchards. In addition, growers consider peaches better than apples due to market and price considerations. With the increase in the demand and price of organic products, the organic system is facing high pest pressure due to fewer management options compared to the conventional system, which requires the development of integrated plant nematode management strategies.

One of the damaging agents for wheat is the cereal cyst nematode (Heterodera avenae). Plant Growth Promoting Bacteria (PGPR) are a group of bacteria that have beneficial properties for plant growth, including iron chelation, siderophore production, phosphate dissolution, nitrogen fixation, as well as the production of protease and chitinase enzymes. These bacteria can also be used as biological control agents. In this study, wheat roots showing suspicious symptoms of cereal cyst nematode were collected from the Dezful county in Khuzestan province during 2022-2023.  After initial investigations, nematode identification and purification was done. According to the morphometric and morphological characteristics of the larvae and cysts, especially its cone top, H. avenae was diagnosed. the effect of seven native growth-stimulating bacterial strains on egg hatching rate and mortality of cereal cyst nematode larvae in the Petri dish was investigated in the laboratory. The effect of four selected bacterial strains with sulfur treatment and Nematex EC nematicide was investigated in the greenhouse against grain cyst nematode. The results showed that in laboratory conditions, the bacterial strains were able to reduce the egg hatching rate by 62% on average. Bacillus pumilus bacteria caused the greatest decrease in egg hatching by 73%. The percentage of mortality of larvae in the laboratory test was also shown to be 63% on average, and the treatment of B. pumilus bacteria showed the highest percentage of mortality with 70%. The results of the greenhouse investigations showed that the treatments involving sulfur-healthy plants, sulfur-nematode, and the B. pumilus and P. fluorescens bacteria were most effective in promoting healthy plant growth and controlling nematode infestation. These treatments resulted in significant improvements in plant height, as well as fresh and dry plant and root weights. Additionally, the greatest reduction in the number of cysts was observed in the B. pumilus treatment, with an average of 49 ± 1 cysts. When examining the number of eggs within the cysts, the most substantial decrease was observed in the Nematex EC and B. pumilus bacteria treatments, with 67 ± 1 and 111 ± 2 eggs, respectively. Furthermore, in the assessment of the number of live larvae in the pot, the greatest decrease in the number of larvae was observed in the Nematex treatment, with 87 ± 1..

The wheat aphid, Schizaphis graminum, is deemed one of the most significant grain pests, causing substantial damage to the country's wheat farms. Consequently, various biological, agronomic, and chemical methods are used to control wheat aphids, where chemical spraying is the most common method. The increasing use of chemical insecticides has resulted in several issues, including the emergence of insect resistance to pesticides, adverse effects on the environment, beneficial organisms, and humans, and the development of insecticide-resistant pests. In this regard, insect pathogens like nematodes may be preferable to chemical insecticides. This study aimed to evaluate the lethal and sublethal effects of entomopathogenic nematode Steinernema carpocapsae on the life history parameters and phenoloxidase enzyme activity of S. graminum by L-DOPA (L-dihydroxyphenylalanine) substrate. This enzyme activity is essential to the insect's innate immune response.

S. graminum was cultivated on a wheat host in a growth chamber maintained at 25 ± 2 °C, 60 ± 5% relative humidity (RH), and 16:8 light/day (L:D) hour photoperiods. Daily observations and recordings were used to track the development period and survival rate. In addition, for breeding the wheat aphid S. graminum, populations from the plant protection department's laboratory were utilized and transferred to wheat plants in a growth chamber.
Aphids infested the plants once they had reached their optimal size. Age-stage and two-sex life table analyses were used to analyze the raw data. TWOSEX-MSChart was used to evaluate the raw data based on the age stage and two-sex life table. In addition, blood cell phenol oxidase and hemolymph testing were performed. Samples of the enzyme were preincubated with phosphate buffer at 30 °C for 30 min, then 50 µl of 10 mM L dihydroxyphenylalanine (L-DOPA) substrate was added and incubated at 25 and 30 °C for 5 min. The phenol oxidase activity was measured using a 492 nm enzyme-linked immunosorbent assay (ELISA) reader device.

The bioassays indicated that the lethal concentration (LC50) of nematode treatment against the adults of S. graminum was 136 larvae/insect. The current study revealed that S. carpocapsae had a higher adult mortality rate than S. graminum. Results of the sublethal effects experiment showed that the pest's fecundity in S. carpocapsae treatment (19.07 offspring/female) was lower than the control (39.16 offspring/female). Furthermore, the studied nematode significantly reduced the population growth parameters of S. graminum. The intrinsic rate of increase for treated and control nematodes was 0.300 and 0.421, respectively, per day. Based on the results, the nematode increased the phenol oxidase enzyme's activity at 25 and 30 °C relative to the control.

Considering that chemical insecticides are accompanied by problems such as resistance and residual toxins in agricultural products, it is preferable to use entomopathogenic nematodes, which have a higher immunity to environment and natural enemies. The lethal concentration (LC50) study of the examined nematode showed that the nematode S. carpocapsae exhibited good disease-causing power on the adult female aphids of S. graminum.
The investigation into the effect of experimental nematode sublethal concentration on the growth parameters of the wheat aphid population revealed that in the nematode S. carpocapsae, the characteristics of the aphid population, particularly the intrinsic rate of population increase parameter value, decreased significantly. Sublethal concentrations of the studied nematode can slow or even stop the population growth of wheat aphids and significantly impact aphid fertility, survival, and life expectancy.
In this study, the phenol oxidase enzyme's activity significantly differed between treated and untreated aphids. It appears that the insect uses phenol oxidase enzymes to counteract the nematode's effect, and this enzyme plays a role in the wheat aphid's body when dealing with S. carpocapsae. The overall results revealed that S. carpocapsae exhibited high lethal and sublethal effects on S. graminum. After additional field studies, it can be recommended for use in biological control and an integrated pest management (IPM) program for this pest.

 Meloidogyne incognita is the most well-known root knot nematode, with more than 2000 host species. Integrated nematode management (INM) is recommended to manage the destructive plant parasitic nematode. Integrated management is generally performed by using the maximum available management methods (at least two methods) and the minimum use of chemical nematicides to bring the pathogen population below the economic threshold. The use of resistant cultivars is of particular importance in integrated management, due to environmental compatibility, economic efficiency, and sometimes the impossibility of implementing other methods, especially in developing countries. Therefore, it is necessary to evaluate the resistance of the important barley plant (Hordeum vulgare) to prevent damage and also to investigate nematode interactions with it.

 In the current study, the resistance of different barley cultivars (i.e., Nik, Nimrouz, and Zarjow) was evaluated based on plant growth factors (length, fresh, and dry weight of aerial part and roots) and nematode gall index at 60 days post inoculation. Then the activity of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) enzymes were measured on days 0, 1, 2, 3, and 4 days post inoculation.

 Regarding the mean number of galls, the Nik cultivar showed a significant difference compared to Nimroz and Zarjow cultivars (P ≤ 0.05). However, no significant difference was observed between Nimroz and Zarjow cultivars. Based on plant growth factors, M. incognita nematode was found to have a negative effect on the aerial part length and weight and a positive effect on root weight. Evaluation of the gall index showed Nik is moderately susceptible, and Nimrouz and Zarjow are moderately resistant cultivars. SOD enzyme in Nik, Nimrouz, and Zarjow showed maximum activity in 2.72, 1.91, and 2.15 U mg-1 protein on the 4, 4, and 3 days post inoculation, respectively. The enzyme in Nik was determined to be 1.42 and 1.25 times higher than Nimrouz and Zarjow. There was a significant difference between 0, 1, and 2 with the 3 and 4 days of the infected samples in Nik (P ≤ 0.05). In the other cultivars, enzyme activity increased with a slight slope. CAT enzyme peaked in Nik, Nimrouz, and Zarjow at 0.204, 0.09, and 0.11 μmol min-1 mg-1 protein on the fourth-day post inoculation. In the Nik cultivar, unlike the other two cultivars, the enzyme increased more and had a steep slope from the second to the fourth day. In infected plants of Nimrouz, despite the gradual increase of enzyme, no significant difference was found between any of the days. APX enzyme peaked at 0.26, 0.27, and 0.24 μmol min-1 mg-1 protein in Nik, Nimrouz, and Zarjow on the fourth day, respectively. The activity of the above enzyme had an increasing trend in three cultivars. The maximum activity of this enzyme was at Nimrouz, which was determined to be 1.03 and 1.1 times higher than Nik and Zarjow, respectively. In this cultivar, the upward trend was rapid, although there was a significant difference between all-time points at the level of 0.05. In the current research, it was found that the invasion of the root knot nematode M. incognita reduces the growth of length, fresh and dry weight in the aerial part, reduces the length of the root but increases the fresh weight of it.

The hallmark of inducing pathogenicity in the sedentary root knot nematodes is the formation of special feeding cells named giant cells, which require controlling the expression of host genes and manipulation of plant hormones like auxin and cytokinin hormones. It is obvious that during the invasion of root knot nematodes and the formation of giant cells in host roots, the plant is weakened due to impaired transport of water and nutrients, and the host growth factors, especially in the aerial part, are reduced. However, due to hormonal disorders and the formation of galls, the weight of the roots increases. The higher expression of antioxidant enzymes superoxide dismutase, catalase, and ascorbate peroxidase in Nik possibly has occurred due to the compatible interaction, as a result of lack of necrosis and programmed cell death and to tolerate stress (nematode invasion). Less expression of SOD, CAT, and APX enzymes in Nimrouz and Zarjow cultivars possibly have occurred due to their moderate resistance to M. incognita invasion.

Legumes are the second most significant plant source of human protein-rich diets after cereals. Additionally, these plants improve soil structure through biological nitrogen fixation. Plant pathogens are one of the most important global constraints on chickpea production. Plant-parasitic nematodes are key damaging agents to crop production. Broad beans, soybeans, lentils, beans, mung beans, and chickpeas are hosts for P. ritteri, and under greenhouse conditions, this nematode reduces the majority of plant growth indices. Various methods are employed to control plant-parasitic nematodes, most of which rely on chemical control. This study was conducted under laboratory and greenhouse conditions to examine the effects of refined wood vinegar, unrefined wood vinegar, chloro carboxylic acid, and sodium dioctyl sulfosuccinate on P. ritteri.

In this study, 66 soil and plant root samples were collected from chickpea fields in Lorestan province's counties. P. ritteri nematodes were identified after extraction using conventional techniques. The number of P. ritteri nematodes per kilogram of soil in an infected field soil was determined, and this soil was subsequently used in laboratory and greenhouse experiments. The effect of four compounds, including refined wood vinegar, unrefined wood vinegar, chloro carboxylic acid, and sodium dioctyl sulfosuccinate, on P. ritteri was investigated under laboratory and greenhouse conditions, as was the mortality of P. ritteri in chickpea. The data were analyzed using SPSS22 software, and tests were conducted using randomized complete block designs.

A comparison of the mean mortality of P. ritteri under laboratory conditions revealed that the highest mortality was associated with a 1% chloro carboxylic acid treatment for 24 h (100%), and the lowest mortality was attributed to a 0.5% refined wood vinegar treatment for 12 hours (25%). Under greenhouse conditions, the chloro carboxylic acid treatment resulted in the highest mortality, 1% (94%), while the unrefined wood vinegar treatment had the lowest mortality, 0.5% (49%). In addition, the mortality rate demonstrated a significant difference at P≤0.05 in two frames of 12 and 24 h for most compounds (except for sodium dioctyl sulfosuccinate 0.5%) and at P≤0.01 in two levels of 1% and 0. 5% for all compounds.

All investigated compounds induced nematode mortality, with chloro carboxylic acid proving to be the most effective for nematode mortality and unrefined wood vinegar the least effective. Consequently, these compounds can be used as pre-planting to control these nematodes.

The stem and bulb nematode, Ditylenchus dipsaci, is an important and damaging pathogen in a number of agricultural and ornamental plants, including alfalfa. The aim of this study was to investigate the effect of raw and pure saponins of six alfalfa ecotypes on the hatching of this nematode's eggs in order to find a biological method for its management.

The effect of raw and pure saponins of six alfalfa ecotypes on the hatching of stem nematode eggs was investigated in a completely randomized factorial design with two factors of alfalfa ecotypes (six ecotypes) and their saponins (raw and pure) in vitro.

Analysis of variance showed that the interaction effect between two factors, ecotype and saponin, is statistically significant. At concentrations of 50 and 90 microliters of crude saponin from different ecotypes, 30-42% and 33-59% of the nematode eggs did not hatch, respectively. The Nishaburi ecotypes caused the most and the Shiraz and Khrisari polycross caused the least number of egg hatching. Concentrations of 10 and 50 microliters of pure saponin resulted in between 56 and 69% and 61 and 79% of total nematode eggs failing to hatch, respectively. The local ecotypes Miandoab and Nishaburi had the highest and Shiraz Polycross the lowest number of egg hatches.

Pure saponins of alfalfa ecotypes have a greater effect on nematode egg hatching than raw saponins. Saponins of Shiraz Polycross alfalfa ecotype have a better effect than other ecotypes.

The lateral bud death disorder in almond (cv. Shahroud 12) is observed in some replanted orchards in Chaharmahal and Bakhtiary province. The abundance of plant parasitic nematodes, phytophthora species and zinc deficiency were more in trees with symptoms than the asymptomatic trees. Experiment was performed in a randomized complete block design with seven treatments including pesticides like fluopyram (Velum Prime®; EC, 41.5%), Abamectin (Vertimec®; EC, 1.8%), Fosetyl-Al + Propamocarb (Previcur Energy®; SL, 840), Fosetyl-Al (Elite®; WDG, 80%), Diazinon (Bazodin®; EC, 60%) , Zinc sulfate (ZnSO4H2O, 33%) and control with five replications on Shahroud 12 cultivar almond trees along Zayandehrood during 2018-2020. A week before the application of chemical treatment and three months later, soil and root samples were collected for the measurement of plant-parasitic nematode population and isolation of Phytophthora species and the zinc content. Four branches per tree were selected from different directions, a week before the chemical treatment and five months later, and  healthy (containing leaf and fruit) and dead buds were counted. The results show the treatments of Velum Prime, Abamectin, Diazinon, Zinc sulfate, Previcor and Elite reduced the bud death and improved the disorder of the almond trees by 66.1%, 53.2%, 36.3%, 33%, 19.3% and 16.9%, compared with the control, respectively. Although compounds with nematicidal properties were more effective in improving this disorder; other treatments were also significantly different compared with control in terms of reducing the symptoms of bud death. The role of other factors in causing this disorder can not be ignored; therefore, the interactional effects of these factors in causing or exacerbating  the symptoms of  bud death of almond (Shahroud 12 cv.) may be more effective than a single cause alone.

Biological pesticides have advantages to chemicals that safety to non-target organisms is of the most important ones. Slugs are parasitized or preyed by several organisms such as nematodes. In this research, integrated management of grey slug Parmacella ibera was assessed by Phasmarhabditis hermaphrodita, Metaldehyde and Fericol in field conditions in Someh Sara, Guilan Province. The treatments included: untreated, P. hermaphrodita recommended dose, P. hermaphrodita recommended dose + Fericol, P. hermaphrodita ½ dose and P. hermaphrodita ½ dose +Metaldehyde ½ dose on P. ibera assessed based on the percent of dead slugs, mean percent of damaged leaves, the number of leaves with damage symptoms and the number of plants with damage symptoms. Results showed the highest percent of dead slugs in P. hermaphrodita ½ dose +Metaldehyde ½ dose. Mean percent of damaged leaves was not significantly different among P. hermaphrodita treatments along with Fericol and metaldehyde. Results indicated that P. hermaphrodita ½ dose + Metaldehyde ½ dose treatment had considerable effect in all parameters on pest control besides a decrease in the damage.

The genus Hexatylus Goodey, 1926 belonging to the family Neotylenchidae is distinguished from other members of the family with cephalic framework with eight sectors, the presence of strengthening rings around stylet, forked stylet at base, dorsal gland orifice near the base of stylet, lumen of esophagus joins lumen of intestine in region of nerve ring, esophagus glands overlap intestine dorsally, mono pro-delphic gonad in females, vulva as a transverse slit, close to anus, genital branch without post vulval sac, tail short, with sharp end and pointed tip. Goodey (1926) reported Hexatylus viviparus associated with diseased potato tubers in England. The nematode is spread worldwide and there are reports of this species in Europe, Asia and America. A population of this species was collected from the soils of Chaldoran, West Azarbaijan province and the nematodes were extracted using combined sieving and centrifuge method and after killing, fixing, transferred to anhydrous glycerin. They were mounted on microscopic slides and the morphological and morphometrical characters studied using an Olympus AX70 optical microscope and digital images prepared by a connected camera to the microscope.

The Hoplolaimidae family is one of the largest and economically most important families of the order/ infraorder Tylenchida / Tylenchomorpha. The members of this family spread all over the world and can be found under different climatic conditions. Some species in this family are serious plant parasites and significantly reduce crop yields.

In the forests of Khorramabad city in western Iran 70 samples were collected from the soil around the roots of hawthorn trees in the period of 2017-2019. After recording the properties of each sample, they were transferred to a laboratory and cooled at 4 °C. The nematodes were extracted from the soil using the tray method, then fixed and transferred to pure glycerin, and permanent slides were made. The morphological and morphometric properties of the nematodes were examined using a light microscope equipped with a Dino Capture camera. The nematode species were identified using scientific identification keys.

Five species of plant parasitic nematodes belonging to two genera of Hoplolaimidae were identified in this study, including Rotylenchus goodeyi, Helicotylenchus canadensis, H. digonicus, H. vulgaris and H. tunisiensis.

R. goodeyi is reporting as a new record for the nematode fauna of Iran. Morphometrical and morphological characteristics of these nemadodes are described here.

Citrus production is very important in term of economical and productivity in south of Kerman province, Iran. During recent years, occuring a new decline disease caused sever threat in citrus orchards in south part of Iran. The disease symptoms starting with significant growth retardation of infected plants. Sever  root rot can be seen easily on infected trees. In this research, the partial distribution of citrus declining disease, the population of citrus root nematode (Tylenchulus semipenetrans) and Phytophthora nicotiana were counted in bouth healthy and infected trees. The partial distribution of citrus decline was 76 percent. The results showed that the investigated samples were infected to citrus root nematode moderate to sever level. The mean of female nematode population per gram root of infected and healthy plant reported 210 and 11 respectively. The mean of 2nd larva populations per 200cm3 soil samples of infected and healthy plants were calculated 2573 and 183 respectively. The numbers of propogules of P. nicotiana in one gram soil rhizosphere of infected and healthy trees reported 13.5 and four respectively. Inoculations of bakraee seedling (rootstock) with nematode and Phyophthora showed sever root rot and nematode infection and finally death of plants. Based on the results of this research, a complex of Phytophthora and citrus nematode are involved in citrus decline disease and can affect the disease severity in south of Kerman.

In order to identify the plant parasitic nematodes in Alborz Province, some soil and root tissues of plants samples were collected from different crops in of Mehrshahr, Nazarabad, Taleghan, Hashtgerd and Karaj through 2017-8. After transferring the samples to the laboratory, soil and root washing operations, nematode extraction, transferring and fixing in pure glycerin were performed. Permanent microscopic slides and incisions were made from different parts of the body of some species. After microscopic observations, the necessary measurements and drawing of the required images, the extracted species were identified using different keys. During the survey and morphological studies, eight nematode species belonging to four genera were identified as follows: Cephalenchus leptus, Filenchus afghanicus, Filenchus discrepans, Filenchus misellus, Filenchus thornei, Discotylenchus discertus, Paratylenchus Lepidus, Paratylenchus straeleni Among the identified nematodes, the species Discotylenchus discertus is reported for the first time in Alborz province and for the second time in Ian.

Plant parasitic nematodes are distributed in all agricultural soils and attack nearly all crops, damage and cause disease. In studying biology, management and other aspects of plant parasitic nematodes, their precise identification should be carried out up to species level. Kahaq region, Maragheh, East Azarbaijan province, is a natural ecosystem and under cultivation of agricultural crops as well. Fruit trees such as walnut, almond, apple, quince and crops like wheat, barley, chickpea and fruitless trees as spruce and willow are grown in the region. Due to the paucity of previous studies the current study set out for the identification of nematode fauna in soils of this region.
In order to identify plant parasitic nematodes, 70 soil samples were collected from the rhizosphere of different vegetations in Kahaq region, Maragheh, East Azarbaijan province during 2014 and 2015. The samples were transferred to laboratory and nematodes extracted by centrifugal flotation technique were transferred to anhydrose glycerin according to the modified De Grisse (1969) method. Permanent slides were prepared from the extracted nematodes and some cross sections were also made from different parts of some nematode bodies if needed. The nematodes were studied under light microscope. The morphometric data were taken using a drawing tube attached to the microscope. Drawings were done using Corel DRAW X7 software. Pictures were taken using DP50 digital camera attached to the microscope.
The results of this study led to the identification of Amplimerlinius globigerus, Criconemoides informis, Mesocriconema antipolitanum, Ogma cobbi, Pratylenchus neglectus, P. thornei, Pratylenchoides erzurumensis, Xiphinema index, X. pyrenaicum, Xiphinema sp. and Zygotylenchus guevarai.
Morphological and morphometric characteristics of two plant parasitic nematodes out of 11 identified species were described in details. Ogma cobbi shows much similarity with O. nemorosus, but the latter differs from the former species because of fewer number of body annuli (45-54 vs 58-61), shape of scales in mid-body (triangular, with rounded tip vs rather acute), empty spermatheca vs full of sperm, occasional presence of smaller scales between rows, especially on posterior half of body (vs not). Xiphinema sp. becomes more similar to X. brevisicum, but is separated from it by lower a value (53-67 vs 72.5-98), cˊ value (1.5-2 vs 2.2-3.1), greater odontostyle length (77-86 vs 57-65 μm) and shorter tail length (27-31 vs 35-47 μm). It also differs from other species of the genus and, hence, considered as an undescribed species.

Citrus nematode is one of the most important damaging nematodes of citrus trees, spreading widely in most areas under citrus planting causing dieback, the gradual decline of trees and crop decrease in citrus orchards. Eighty citrus cultivars and species are sensitive to this nematode. From other nematode hosts, we can refer to olive, fig, medlar, persimmon, pear and grapevine. Surveys Full filled in Mazandaran province is indicative of the widespread of this nematode in citrus horticulture and the level of infection in some samples is so high, thus it is necessary to use different ways of controlling this parasite.
This research was carried out for 2 successive years and the reaction of sin citrus rootstocks including Citromelo, Poncirus, Sour Orange, Bakraee, Rough lemon and Off-type to citrus nematode under controlled conditions in the greenhouse was evaluated. Three months years old plants of this rootstock Were planted in completely random design with 5 replications in pots containing the population of 40 larvae per cubic centimeter of soil and after six months, the level of infection of roots was investigated and then the most tolerable rootstock for nematode was introduced on the basis of the least population of young females and adult females injected in one gram of root volume.
Experiment results on the basis of LSD test in two successive years indicated that there is a meaningful statistical difference between Citrumelo and poncirus Poncirus with the least population of nematode of adult female on the root and other treatments the results show that sour orange and off-type rootstocks are the most sensitive to citrus nematode, poncirus Poncirus and Citrumelo are the most tolerable to nematode Bakraee and Rough lemon are in the biotype group with average tolerance (relatively sensitive) to citrus nematode. Purpose of this research is to assess the sensitivity level of six citrus rootstocks including Citromelo, Poncirus, Sour Orange, Bakraee, Rough lemon and Off-type some of these rootstocks are common citrus rootstocks in the North and south citrus regions of the present time, therefore it is necessary to choose appropriate rootstock. In addition to it, another purpose (aim) of this research is to assess tolerance of new off-type biotype, produced from citrus breeding programs, to citrus nematode under greenhouse conditions in comparison with Citromelo, Poncirus, Sour Orange, Bakraee and Rough lemon which are common citrus rootstock in the North and South provinces of the country. Bakraee is one of the natural types of citrus used in citrus regions of Fars, Hormozgan and Kerman as rootstock of mandarin and orange cultivars for many years. Introductory surveys concerning Bakraee tolerance to coldness, the rot of crown and root, and diseases such as Tristeza, Exocortis and Cachexia were carried out but its tolerance to citrus nematode has not surveyed yet. Recent molecular surveys showed Bakraee relationship with Rough lemon beside, because of appearing unknown disease of citrus trees decline on Bakraee rootstock from the beginning of 1389 in Jiroft mountainous regions, doing etiology studies and investigating its tolerance to disease factors such as citrus nematode is of great importance. Since this nematode is soil parasite and can live in the depth of soil, its chemical control is very difficult. Despite the fact that one of the control methods of it is soil sterilization before citrus planting, but because of increasing environmental risks and bad effects on human health, it is recommended that resistant rootstocks such as Poncirus should be planted in the nematode soil. Also, it is necessary to control plants in selling time from the aspect of infection and, if necessary, to sterilize infected plants in order to prevent infection spread and build healthy orchards. Therefore regarding the fact that rootstocks of Poncirus and Citromelo are resistant to Tristeza and gummosis and identifying their resistance to citrus nematode, so planting of these rootstocks in the North of the country can be effective in managing citrus nematode in infected areas. In fact, investigating resistance of common rootstocks in the region and having access to resistance sources can be regarded as a method for sanitation of plants and as a result for controlling this nematode and increasing yield in the region. Also, the results of this survey can help horticulturists to introduce and produce appropriate rootstocks in the south of the country.

Root lesion nematodes are one of the most important and fatal plant parasites. They often move between soil and host plants roots, during all stages of their life. Root lesion nematodes migrate and feed within the roots, therefore they cause necrotic lesions on the surface and throughout the cortex of infected roots. Their attack to the root can result stunting of plant root system as well as reduction in plants growth and eventually host kill. Different management methods such as the planting of resistant genotypes, crop rotation, fallow periods and use of biological control agents are successfully practiced against these nematodes. In this paper a brief discussion of economic damages, importance, taxonomy, biology and symptoms of Pratylenchus thornei attack and the most efficient management methods are presented.

Gossypium species are distributed in the arid to semiarid regions of the tropical and subtropical, generally shrubs or shrub-like plants. The leaves are broad and lobed with three to five lobes. The seeds are contained in a capsule called a "boll", each seed surrounded by fibers. Commercial species of cotton plant are Gossypium hirsutum (>90% of world production), G. barbadense (3-4%), G. arboreum and G. herbaceum (together, 2%). Cotton is grown as a cash crop; it is often grown in a monoculture system that favors the development of a nematode community dominated by one or a few parasitic species. The different genera of plant parasitic nematodes such as Haplolaimus, Helicotylenchus, Blanolaimus, Pratylenchus, Paratrichodorus, Meloidogyne, Merlinius, Xiphinema, Tylenchorynchus, Rotylenchulus, Scutellonema, Heterodera, Ditylenchus, Longidorus, Aphelenchoides, Aphelenchus were recorded from cotton fields in the world. The objective of this study was to investigate the plant parasitic nematodes associated with cotton fields in Southern Khorasan province of Iran.
In order to identify the plant parasitic nematodes in cotton fields in Southern Khorasan province, 56 soil samples were collected from different areas during 2013 and 2014. Soil samples were washed and nematodes were extracted by combined sieving and centrifugal-flotation method of Jenkins (1964) and Whitehead tray method (1965). Nematodes were fixed and transferred to glycerin by using the method of De Grisse (1969). The permanent slides were prepared and the nematodes were studied by light microscope.
In this study, 15 species from 10 genera related to order Tylenchomorpha, were identified as follows: Aphelenchus avenae, Basiria graminophila, Boleodorus clavicaudatus, B. pakistanensis, B. thylactus, Ditylenchus hexaglyphus, D. tenuidens, D. valveus, Geocenamus rugosus, Filenchus vulgaris, Pratylenchus neglectus, P. thornei, Scutylenchus quadrifer, Merlinius brevidens, Zygotylenchus guevarai. One genus of cotton-parasitic nematodes known to cause yield loss were found in this survey (Pratylenchus spp). Other parasitic nematodes not known to cause yield loss also were found. Three species, including Boleodorus pakistanensis, Ditylenchus hexaglyphus, D. valveus are reported as new records for Iran. Boleodorus pakistanensis is characterized by four incisures, head low, unstriated and conoid shape, stylet 8.5-10µm with cone short and slender knobs, non-muscular median bulb, Basal bulb pyriform, posterior vulva (v=68.1-72.4 ; v/=77.5-88.4). Tail elongate-conoid, central arcuate, ending in a finely rounded terminus. B. pakistanensis resembles, B. flexuosus B. teres, B. thylactus and B. cylindricus. B. thylactus but can be differentiated by the more posterior position of the opening of the dorsal gland (2 vs 3-5); B. flexuosus has a more anterior vulva (V=54-63 vs 68.1-72.4); B. teres has a more anterior vulva (V=54-63 vs 68.1-72.4), tail shape and stylet length (10-12 vs 8.5-10); B. cylindricus has a more anterior position of the opening of the dorsal gland (7 vs 3-5) and more tail (88-101 vs 72-88.5). Ditylenchus hexaglyphus is characterized by six lines in lateral fields, low head, stylet 8-9µm with cone shorter than the shaft and small elongated knobs, non-muscular median bulb, Posterior bulb offset, posterior vulva (v=82.3 -83.5; v/=87.8-89.6). Tail ventrally curved, terminus rounded. Having non-muscular median bulb, six incisures, short stylet and posterior vulva. D. hexaglyphus resembles D .medians, D. taylori, D. affinis, and D. tuberosus. However, none of these species have such small stylet knobs, and all but D. affinis have longer PUS than that observed in D. hexaglyphus. D. taylori more anterior vulva (V=75-77 vs 82.3-83.5) and tail appears to be thinner (c/=6-7 vs 2.9-3.8); D. affinis has a more anterior vulva (V=76-80 vs 82.3-83.5). Ditylenchus valveus is characterized by six incisures, annulated head, stylet 8-9µm with short cone and small rounded knobs, muscular median bulb with small. Posterior bulb offset, posterior vulva (v=74.3 -81.5; v/=84.9-89.2). Tail terminus rounded. Because of six incisures, short stylet, vulva position, oesophagus structure and tail shape, D. valveus resembles D. acutatus D. myceliophagus and D. medicaginis. D. myceliophagus differs from D.valveus by tail shape and generally overlapping oesophagus; D. medicaginis differs from D. valveus mainly by tail shape and also slightly more posterior vulva position (78-83 vs 74.3-81.5); D. acutatus differs from D. valveus mainly by tail shape.
In this study, 15 species from 10 genera of plant parasitic nematodes were identified. Among these genera and species, three species including Boleodorus pakistanensis, Ditylenchus hexaglyphus, D. valveus are reported as new records for Iran.