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Tomato is attributed as a global host for root-knot nematode (Meloidogyne incognita) soliciting ponderous damage. Using biocontrol agents to control plant parasitic nematodes is a well-established, green approach in advance of synthetic nematicides. The role of Bacillus spp. in inciting physiological and biochemical alterations in nematode infestation is discussed in the present study. The susceptible (PKM-1) and resistant (Hisar Lalit) tomato cultivars treated with Bacillus pumilus augmented the shoot length, root length and biomass of plants compared to the standard check, Pseudomonas fluorescens, followed by B. megaterium. Accordingly, all the biocontrol agent-treated susceptible plants showed reduced galling and exhibited a root gall index of 3 (moderately resistant). Contrarily, all the resistant plants showed highly resistant reactions. B. pumilus showed the topmost expression of all the biochemical enzymes like peroxidase (PO), polyphenol oxidase (PPO), catalase (CAT), phenylalanine ammonia-lyase (PAL) and total phenols. Conclusively, B. pumilus was found to be the most potential in reducing nematode infestation by embellishing the plant growth and enhancing defense-related enzymes in tomatoes.

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A survey of cereal fields of Khuzestan province during 2008-2011 revealed that cereal cyst nematodes (CCNs) are widely distributed in this region. The CCNs were present in 37 and 35% of the 200 samples collected from wheat and barley fields respectively. The species were identified as Heterodera avenae type B and H. filipjevi the morphological and morphometric identifications of which were confirmed by rRNA-ITS RFLP. Population density of CCNs ranged from 2 to 103 cysts (mean 18)/100 g of dried soil with an average of 395 (0-3400) J2 and eggs in wheat samples. Whilst the number of cysts in barley samples were counted 3-71 cysts (mean 11) /100 g soil, the J2 and eggs averaged 166 (0-900). The lowest and the highest rates of infestation (8 and 83%) were observed in the regions of Ahvaz and Behbahan respectively. The number of J2 and eggs of CCNs in some regions were greater than the damage threshold level considered for CCNs and it is likely they could cause economic yield loss in these regions.  

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During a survey on the identification of plant-parasitic nematodes associated with walnut in Sanandej region (Kurdistan province, western Iran), a population of Paratylenchus labiosus was collected and identified morphologically. Description, illustrations and morphometrics of the species are given and comparisons are made between it and some related species. Paratylenchus labiosus comes more close to three species namely P. similis, P. tateae and P. italiensis in having certain diagnostic characters such as short stylet less than 18 µm long, concave-conoid head with prominent submedian lobes and tail ending to an acute to finely rounded terminus. However, P. labiosus differs from them in having a spermatheca full of sperm cells and presence of males. Different modes of reproduction (parthenogenesis or amphimixis) may be observed in different populations of some species in this genus, but somewhat unique reproduction behavior of P. labiosus could be considered as a diagnostic character for separation of it from the three closely related species.      

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Application of antagonistic agents in the rhizosphere of plants is an important approach in control of soil-borne pathogens. Establishment and persistence of biocontrol agents in the soil is a major concern in biological control. This study aimed to determine the effect of plant debris of oak forests on activity of Pseudomonas fluorescens and Trichoderma vierns against Meloidogyne javanica in tomato in green house conditions. In different treatments, both or one of the bioagents were applied to the soil inoculated with M. javanica and amended or unamended with oak plant debris. Based on the results, the growth–related factors of tomato improved in those treatments, in which plant debris were mixed with the soil. In case of nematode-related factors, the number of galls on roots decreased significantly in pots amended with plant debris. Maximum reduction in reproduction factor was observed in treatments with one or both of the biocontrol agents. In comparison to unamended treatments, the rate of reduction in root gall was 56.3% for treatments receiving T. virens and maximum increase in dry weight of root was observed in soils treated with P. fluorescens or T. virens, 68.2% and 56.1%, respectively.

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Three species of Paratylenchus were collected and identified from vineyards and apple orchards in Kermanshah province, western Iran. Descriptions, morphometric data, line drawings and microscopic photographs are provided for these three species. Paratylenchus audriellus and Paratylenchus straeleni are the two very closely related species, with a stylet longer than 40 µm, four lateral lines and distinct vulval flaps. The third species, Paratylenchus leptos, has a shorter stylet, three lateral lines and distinct vulval flaps. Paratylenchus leptos is a new record for Iranian nematode fauna, and male of P. audriellus is reported from Iran for the first time.  

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During a nematological survey, nineteen known species of plant-parasitic nematodes belonging to the family Tylenchidae (Tylenchomorpha: Tylenchoidea) were collected and identified from different localities of West Azerbayjan and Kermanshah provinces, Iran. Among them two species, namely Discotylenchus attenuatus and Tylenchus bhitaii, are new records for Iranian nematode fauna, the male of T. bhitaii is recorded for the first time. Also, two previously reported species Filenchus quartus and Tylenchus stachys are illustrated and described. Descriptions, morphometric data, line drawings and microscopic photographs are provided.
 

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The study was conducted to determine the distribution of the common Meloidogyne species in research stations and vegetable farms in Ibadan, south-western Nigeria. Galled roots were collected from inoculum plots of four research stations and two vegetable farms. Identification of species was based on juvenile and female morphological characters and specific SCAR primers for Meloidogyne species. The pathogenicity of M. incognita and M. javanica was evaluated at different inoculum levels on tomato in a screenhouse study. M. incognita was the dominant species encountered in research plots, although it often occurred in mixed population with M. javanica and other unidentified species. Growth parameters such as plant height, number of leaves, and yield responded negatively to increasing inoculum levels for all the cultivars except Small Fry and Celebrity. Both cultivars were categorized as resistant to M. incognita and tolerant to M. javanca. The most popularly grown tomato cultivars, Ibadan Local, Roma (Roma type) and Beske were susceptible to both species of root-knot nematodes.  

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Eight species of Paratylenchus were collected and identified from vineyards in Kermanshah province, western Iran. Description, measurements, line drawings and microscopic photographs are provided for two new records namely P. humilis and P. prunii. Paratylenchus humilis have a lip region truncate-conoid with distinct small submedian lobes in lateral view of female head, stylet shorter than 40 µm, three lateral lines and distinct vulval flaps. Paratylenchus prunii have a lip region rounded (slightly truncate in some specimens), without distinct submedian lobes in lateral view of female head, stylet shorter than 40 µm, four lateral lines and distinct vulval flaps. Male of P. straeleni is reported for the first time.  

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During a nematode survey and identification of plant-parasitic nematodes in Iran, several species belonging to the infraorder Tylenchomorpha were collected and identified from different localities of West Azerbayjan, Kermanshah and Golestan provinces. Among which three species, namely Aphelenchoides xui (Aphelenchoididae), Paratylenchus recisus (Tylenchulidae)and Tylenchus skarduensis (Tylenchidae) are new records for Iran nematode fauna. Description, measurements, line drawings and microscopic photographs are provided for these new records.

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Potato cyst nematodes (PCN), Globodera rostochiensis and Globodera pallida are major limiting factors to potato cultivation globally. Effective use of nematode antagonistic bio-agents is a potentially important component of the eco-friendly agro-farming. Pseudomonas fluorescens and Purpureocillium lilacinum are known for their nematode antagonistic potential and plant growth promotion ability. The effect of seed treatment with liquid suspension of P. fluorescens at 1 l/ton seeds and soil drenching with suspension of P. lilacinum at 5 l/ha, singly and jointly, was studied to minimize the damage caused by PCNin potato plants under field conditions in two regions in India. Both applications showed significantly greater PCN suppression and better plant growth promotion in comparison to solo application. The both application showed the highest reduction of cyst population (75.7%) in soil, female population (79.9%) in root and egg numbers per soil of each location (84%). The potato plants from P. fluorescens-seed treatment and P. lilacinum-soil drenching both applied plots were 33.5% taller with 45.6% more number of tubers than untreated plants. The tuber yield was also significantly higher (35.9%) in both application than untreated control. There was no significant difference on the root colonization of P. fluorescens and P. lilacinum in solo and both treatments.
 

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The effects of salicylic acid (SA) nano-formulation on expression of peroxidase (113-114) genes and peroxidase and phenylalanine ammonia lyase (PAL) were investigated in wheat cultivar (Bezostaya) susceptible to Heterodera filipjevi. The wheat roots and leaves were randomly divided into control group and groups exposed to 62.5, 125 and 250μg/ml SA. A spectrophotometric analysis was carried out using root extracts from infected plants at 4, 7 and 11days post inoculation with nematode (DAI) for peroxidase and PAL. The expression of peroxidase (113-114) genes was evaluated by Real time PCR analysis. Peroxidase activity was significantly increased in treatments exposed to 250µg/ml of nanosalicylic acid at 11 DAI. Phenylalanine ammonia lyase activity was induced in the treatments exposed to 250 and 125µg/ml nanosalicylic acid compared to the control at 4 and 7 DAI, respectively. Phenylalanine ammonia lyase activity was also increased in the treatments exposed to 62.5 and 250µg/ml of nanosalicylic acid compared to the control at 7 DAI. The expression level of peroxidase 113-114 in wheat leaves was significantly raised at 4 DAI when 62.5µg/ml of nanosalicylic acid was used. There was also a significant difference between expression levels of peroxidase 113-114 genes at applications of 125 and 250µg/ml of SA in comparison with the control at 4 and 7 DAI, a significant decrease was revealed in the gene expression in treatments exposed to 62.5, 125 and 250µg/ml of nanosalicylic acid compared to the control at 11 DAI. It was concluded that higher concentrations of nanosalicylic acid have a potential effect on peroxidase and PAL activities in wheat infected by H. filipjevi. High concentration of nanosalicylic acid has inhibitory effects on the expression level of peroxidase gene.

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The potato cyst nematode Globodera rostochiensis (PCN) causes severe damage to potato production worldwide. The stimulatory effects of root diffusates of 9 plant families on hatch of second stage juveniles (J2) of PCN and their possible use as trap crops were studied. In the laboratory, cysts were placed in leachates from roots and hatched J2s were collected weekly; in addition, the selected plants were grown in soil for 3 months and the rates of decline of eggs from inoculated cysts, were determined in two experiments with various plant species. Species of Solanaceae, such as the susceptible potato cultivar Marfona, tomato and the resistant potato cultivar Agria, induced 84%, 75% and 65% hatch respectively. Moreover, considerable hatching (49%-70%) was caused by exposure to root exudates of weeds of Solanum nigrum and S. villosum. Among non-host and non-Solanaceae plants, 11-32% of J2s hatched in root exudates of treatments of wheat, corn and barley in soil. There were differences in the rates of decline of J2 populations caused by the different plant species examined. In S. sisymbriifolium (a non-host species of Solanaceae) treatment, the density of encysted eggs declined by 62%. The potential of aforementioned plant species, the resistant cv Agria and some other tested plant species as suitable trap crops are further discussed; and in conclusion, the use of the trap crops could be an important component of PCN management program in Iran. 

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The genus Paratylenchus sensu lato includes members belonging to the genera Paratylenchus sensustricto (species with 10 to 40µm long stylet), Gracilacus (species with 40-120µm long stylet), Gracilpaurus (species having cuticular punctuations) and Paratylenchoides (species having sclerotized cephalic framework). Long stylet species become swollen and feed as sedentary parasites of roots, some feed from cortex of perennial host roots, but most species feed as sedentary ectoparasites on roots. In other words, species with stylet shorter than 40µm commonly feed on epidermal cells, whilst the species with longer stylet nourish primarily in cortical tissue, without penetration into the plant tissue. In general, pin nematodes, Paratylenchus spp. are parasites of higher plants with a higher abundance in the rhizosphere of trees and perennials. In present review, an attempt is made to document published information on the pathogenicity and damage potential of the pin nematodes to plants.
 

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The cosmopolitan root-knot nematodes of the genus Meloidogyne are considered as the most important plant-parasitic nematodes damaging almost all higher plant species. This paper provides an updated checklist of 105 valid species of Meloidogyne, along with their synonyms and non-valid members. Furthermore, species are grouped based upon their diagnostic characteristics of second-stage juveniles (tail shape, tail length, stylet length and dorsal gland orifice (DGO) distance from stylet base) and males (number of lateral incisures, stylet length, DGO and spicules length).

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Potato is one of the most important crops produced in Kurdistan province, western Iran. Although several species of plant-parasitic nematodes have been reported in association with these potato fields, no comprehensive nematode community structure has been investigated. The present study reports the frequency, abundance and prominence value of all nematode groups from 40 potato fields across Ghurveh and Dehgolan regions. Bacterivorous nematodes showed the highest frequency, abundance and predominance in the region, followed by herbivorous (plant-parasitic nematodes), fungivorous and omnivorous nematodes. Predatory nematodes (carnivores) were not recovered probably because field soils were highly disturbed. Root-lesion nematodes were the most predominant among the identified plant-parasitic nematodes. The calculation of the indices of ecosystem function, as well as the plotting colonizer-persister (c-p) triangle, food web faunal analysis and metabolic footprint of the potato fields revealed that most of the studied fields had high proportions of c-p1 and c-p2 nematodes, but nematode individuals of c-p3-5 counted fewer in the population. According to the present study, 50% of the sampled fields represent either stressed and enriched, 30% could be considered as stable and enriched, and 20% may be described as stressed and depleted in terms of their soil nematode food webs. The current study provides the first known study in Iran on nematode assemblages and their implication in soil health.

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Root-knot nematodes, Meloidogyne species are among the most critical plant-parasitic nematodes attacking okra Abelmoschus esculentus (L.) Moench in tropical and subtropical regions. In the present study, the effects of various levels of zinc and iron on okra infected with M. javanica were investigated under greenhouse conditions in a completely randomized factorial design with five replications. Four-leaf stage seedlings of the susceptible okra, cv. Clemson Spineless were inoculated with 8000 eggs of M. javanica per pot. Five days later, the soil of each pot was treated with a combination of iron or zinc (0, 1, 3, and 6 mg∙kg^-1 soil) from nano chelated iron and zinc fertilizer sources. Sixty days after inoculation, plants were harvested, and okra growth indices and nematode population indices were determined. Results showed that vegetative indices increased in most cases compared to non-treated plants. Fruit fresh weight of inoculated plants treated with iron at the rate of 1 mg∙kg^-1 soil + zinc at the rate of 3 mg∙kg^-1 soil from nano chelated iron and zinc fertilizer sources increased by 205%, compared to inoculated control plants. Combined application of iron at the rate of 6 mg∙kg^-1 soil + zinc at the rate of 6 mg∙kg^-1 soil from nano chelated iron and zinc fertilizer sources reduced the number of eggs, galls, and egg masses per root system and the reproductive factor (224, 415, 455 and 231%, respectively) compared to non-treated plants.

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In this paper, based on the concept of natural orthogonal complement, an algorithm is devised to analyze the inverse and forward dynamics and dynamic sensitivity of n-linkage planar serial robots. The first goal is to derive the governing dynamic equations of a planar serial robot systematically, more precisely, number of the linkages, mass, moment of inertia and the length of the linkages are the inputs of the algorithm and the output will be the dynamics equations of the robot. As a comparison study, a planar serial mechanism, namely, dynamic modeling of 6R serial revolute manipulator is investigated and the results of the proposed algorithm are compared with other methods, i.e, Adams software and MatODE. In the next step, in order to develop a dynamic sensitivity analysis scheme, Sobol and EFAST methods are employed. By the use of the dynamic equations of the robots, the sensitivity of the actuating torques to the design parameters such as mass and length of the linkages is analyzed. Dynamic sensitivity of three planar serial robots namely, 2R-PSM, 3R-PSM and 6R-PSM is studied in two different configurations such as singular and isotropic. At the end, the effects of various angular velocities on the sensitivity of actuated torques to the design parameters are investigated. The obtained results reveal that the tolerance of uncertainty in the design parameters of robot affects the actuating torques significantly and also the Sobol’s method predict the sensitivity of the robot more precisely.

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To understand the relationship between natural physicochemical properties of soil and abundance of citrus root nematode (Tylenchulus semipenetrans), a survey was conducted during 2009-2010 in some 37 citrus orchards, in Kohgilouyeh va Boyerahmad Province, Iran. Distribution of the citrus nematode was determined by collecting random samples from the soil and citrus plant roots, extracting and enumerating the number of second stage juveniles, males/100 g of soil and females/5 g of root. The relationships between nematode population, and the factors of: organic matter content, Nitrogen (N), Phosphorus (P), Potassium (K), organic carbon, Calcium Carbonate, soil texture, Electrical Conductivity (EC) and pH were determined. Increase in nematode population density was observed by increasing soil saturation percentage (up to 43%), and by an increase in soil silt, sand, P, K and organic carbon, but by an increase in soil salinity, Calcium Carbonate, total Nitrogen and the amount of clay in soil, the nematode population decreased. Maximum nematode population density was recorded in a loamy soil texture. The most suitable soil pH for nematode activity was found almost seven while either an increase or decrease in soil pH, resulted in a decrease in nematode population. The number of second stage juveniles ranged from 58 to 2,730/100 g of soil while females were present by 11 to 331 individuals/g of root respectively. About 62% of the studied orchards were infested with T. semipenetrans.

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The effects of poultry manure and cow dung in comparison with the nematicide, carbofuran on the yield of okra infested with root-knot nematode Meloidogyne incognita Race 2 were investigated. Two plots of 17×11 m, each naturally infested with the mentioned nematode, were selected for the study. Treatments were poultry manure and cow dung each at the rates of 5 and 10 t ha^-1, carbofuran 3G at the rates of 1.5 and 3.0 kg ai ha^-1, and a control. One week after application, okra seeds were sown at two seeds per hole and thinned to one plant, one week after planting. Number of pods, cumulative weight of okra pods, root gall-index, soil chemical properties, and soil nematode densities in soil were determined at the beginning and end of the study. The results showed that the highest rates of poultry manure, cow dung, and carbofuran significantly (P≤ 0.05) reduced root gall-index and nematode population density in soil and correspondingly increased fruit yield in comparison to those at lower rates and the control. The results of this study suggest that incorporation of poultry manure or cow dung in nematode-infested field has the potentials to suppress nematode population and reduce nematode damage on okra. 

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Three species belonging to three genera of the family Tylenchidae, namely, Cephalenchus leptus, Eutylenchus excretorius, and Lelenchus leptosoma were discovered as first reports for Iran's nematode fauna. They were characterized by morphological, morphometric and molecular phylogenetic studies. The two latter genera are new for Iran. Iranian population of Cephalenchus leptus is characterized by lateral field with six lines in females, stylet length of 16-20 µm and tail length of 153-290 µm with pointed tip. The recovered population of Eutylenchus excretorius is characterized by 848-1,038 µm long females’ body, stylet length of 20.0-21.5 µm, having advulval flaps and absence of male. The Iranian population of Lelenchus leptosoma is defined by its narrow slender body, flattened lip region, sinuous amphidial opening and absence of lateral field. The phylogenetic relationships of the three recovered species were studied using the partial sequences of 28S rDNA D2/D3 segment and revealed the genera Cephalenchus and Eutylenchus forming a monophyletic clade, while, Lelenchus was placed inside the clade of currently sequenced species of Malenchus in Bayesian tree.