Introduction: NEMATODES are an abundant and very diverse group among the living organisms of soils. They are few information about them as animals which can live in all habitats including fresh waters, marines, soil of farms, gardens, forests and pastures. In addition to plant parasitic NEMATODES, which have parasitic relationship with different plants in agricultural soils, NEMATODES belonging to other trophic groups also have indirect impacts on the growth of plants in the agroecosystems and nature. They are used as biological indicators of soil health. The knowledge on their abundance, presence or absence of different groups of NEMATODES in the soils are considered important in various biological sciences. Materials and Methods: In order to study the diversity of dorylaimid NEMATODES in Arasbaran forests, 65 soil samples were collected during 2015-2016 from different plant rhizosphere. The soil samples were transferred to the Nematology laboratory-University of Tabriz and kept at four degree centigrade until extraction time. They processed and the NEMATODES extracted, killed, fixed and transferred to anhydrous glycerin using common nematology methods. After preparing permanent microscopic slides, their morphometric and morphological characteristics were studied under optical microscope and identification was done using related valid literature. The morphometric data of nematode and microscopic images prepared using Motik optical microscope connected to scaled lens and future wine camera, respectively. All figures were prepared by Corel draw® 12 software. Results and Discussion: As a result 20 dorylaim species (Crassolabium saccatum, C. himalum, C. ettersbargense, Syncheilaxonchium nairi, Paravulvus hartingii, Eudorylaimus spaulli, Epidorylaimus lugdunensis, Nygolaimus brachyuris, Paraxonchium carmenae, Metaxonchium persicum, Aulolaimus oxycephalus, A. nanocephalus, Discolaimus mariae, Longidorella soadi, Sectonema demani, Xiphinema macroacanthum, X. vuittenezi, X. uthahense, Longidorus africanus, Tylencholaimus constricus, T. tahatikus, Xiphinemella globilabiata, Enchodelus macrodorus which are belonging to 16 genera and ten different families. The family Qudsianematidae had more number of genera (five) and two genera, Crassolabium (three species) and Xiphinema (three species) were found having the most number of species compared to the other genera. Six species namely Discolaimus mariae, Crassolabium saccatum, C. himalum, C. ettersbargense, Xiphinema uthahense and Tylencholaimus tahatikus that are new records for Iran nematode fauna described here in. D. mariae has been reported for the first time around the roots of olive trees in Spain by Pen-santiago. In this study, the nematode was collected and identified in Arasbaran forests-Shirin Bolagh. Comparing the present population of D. mariae with its main description there were not much differences. The only difference was in the c index (80-95 vs. 88-73). The closest species to C. saccatum is C. circuliferum which distinguished from that by non-sclerotized vulval region in C. saccatum. C. diversum as another related species to C. saccatum is characterized by a complete offset head (vs. relatively offset head) and posterior position of vulva (V= 52. 9-57 vs. V = 49-50). This population of C. ettersbargense can be compared to the morphometric characteristics of previous reports that has shorter body length (0. 5-0. 6 mm vs. 0. 6-1 mm). In members of Crassolabium having equal to less than one millimeter body length is characteristic of C. ettersbergense, C. medianum, C. pumilum, C. goaens and C. pumilum. C. medianum species has bubble-like organs in the tail (vs. absence of them in C. ettersbergense). C. pumilum has no pars refringense, and the expanded part of the esophagus is one third of length of the esophagus (vs. absencs pars refringense in C. ettersbergense, and the above ratio is 50-60% of the esophagus). C. goaens distinguished from C. ettersbergense with longer Odontostyle (15-17 vs. 11-12 μ m). The head in C. parvulum, is different in comparing C. ettersbergense (continues vs. offset). Crassolabium himalum comparing the main description has slightly longer tail (25-27 vs. 21-24 μ m. C. himalum is comparable for morphological traits with C. neohimalum and C. porosum. The C. neohimalum is characterized by a shorter body length (1. 07-1. 35 mm vs. 1. 32 to 1. 47 mm) and the asymmetrical lips (vs. symmetrical). The C. himalum is also distinguished from C. porosum by having offset head-(vs. countinouse) and a relatively tall tail (25-27 μ m vs. 21). Xiphinema uthahense is member of Xiphinema americanum-group and compared to the main description and previous reports, there was no significant difference between the morphological traits and the morphology. The species X. taylori, due to the lower coefficient b (5. 6-7. 5 vs. 8-8. 5), has a lower coefficient (39. 3-51 vs. 61-66. 5) and the coefficient c 'less (0. 75-1 vs. 1. 2-1. 7) can be distinguished from X. utahense species. X. pacificum is relatively longer (5. 8-7. 8 vs. 8-8. 5). Tylencholaimus tahatikus in morphological characteristics has similarity to T. mongolicus and T. innebus. Compared to T. mongolicus it has a longer odontostyle (10. 6-15 μ m vs. 7-6 μ m), longer tail (19-22 μ m vs. 8-14 μ m), greater c (44-50 vs. 24-30) and c 'is less (0. 7-0. 9 vs 1-1. 2). In T. innebus, V is greater (V =62-64 vs. V= 53-57) and shorter body length (0. 54-0. 68 mm vs. 0. 90-0. 95 mm).

In order to identify the plant-parasitic NEMATODES (Tylenchida) of fruit trees in Zanjan region, 100 soil and root samples were collected from orchards during 2001 and 2002. The samples were washed and the NEMATODES were extracted by centrifugal flotation technique. They were fixed and transferred to glycerin according to the De Grisse method (1969). The permanent slides were prepared from the extracted NEMATODES and some cross sections were made from different parts of the body. Morphological and morphometrical characters were studied by a light microscope attached to a drawing tube. In this study 17 species belonging to 15 genera of order Tylenchida were identified.Coslenchus assamensis (phukan & Sanwal 1980) Andrassy, 1981 and Paratylenchus nanus Cobb, 1923 are reported from Iran for the first time.

In order to identify the biodiversity of plant parasitic NEMATODES in vegetable fields of Tabriz, during 2004-2005, 88 soil and a few root samples were collected from rhizosphere of 25 dominantly cultivated vegetable crops. NEMATODES were extracted by combined sieving and centrifugal–flotation method and processed to be transferred to glycerin. After preparing microscopic slides, the morphological and morphometrical features of the NEMATODES were studied using the light microscope equipped with a drawing tube. The morphological features and measerments of the extracted NEMATODES were compared with those ones given in literature and similarities and differences with original descriptions and closest species were discussed. As a result, 25 species belonging to 16 genera including Amplimerlinius globigerus, Aphelenchus avenae, Aphelenchoides bicaudatus, A. haguei, A. richardsoni, Boleodorus thylactus, Criconema mutabile, Criconemoides informis, C. mongolensis, Ditylenchus medicaginis, Filenchus vulgaris, Geocenamus brevidens, G. rugosus, Helicotylenchus digonicus, H. exallus, H. pseudorobustus, H. vulgaris, Heterodera cruciferae, Mesocriconema antipolitanum, M. curvatum, Paratylenchus mexicanus, Pratylenchus alleni, P. neglectus, Psilenchus hilarulus and Zygotylenchus guevarai were identified. Most of the NEMATODES are already recoded from Iran and herein, three species namely, Aphelenchoides haguei, Aphelenchoides richardsoni and Pratylenchus alleni and one newly reported species (Helicotylenchus exallus) are described.

In order to identify the NEMATODES associated with fruit trees in Moghan region (orchards), 120 soil and root samples were collected from several orchards in the region during 2004 and 2005. The samples were washed and the NEMATODES were extracted by centrifugal flotation technique. Then they were fixed and transferred to glycerin according to the De Grisse method (1966). The permanent slides were prepared from the extracted NEMATODES. After microscopic consideration, the useful measurement and drawings (morphological and morphometrical characters) were made. In this survey, 28 speceis belonging to 19 genus, were identified as follows: Aphelenchoides limberi, A. cyrtus, Aphelenchus avenae, Aprutides guidettii Basiria flandriensis, Boleodorus thylactus, Coslenchus pycnocephalus, Criconemoides xenoplex, Criconema informis, Ditylechus kheirii, D. medicaginis, D. parvus, Filenchus afghanicus, F. vulgaris, Merlinius rugosus, Helicotylenchus pseudorobustus, Paraphelenehus acontioides, Parartylenchus tateae, P. nanus, Pratylenchus neglectus, P. thornei, P. vulnus, Psilenchus hilarulus, Rotylenchus cypriensis, Zygotyenchus guevarai, Longidorus iranicus, L. profundorum, Xiphinema indexThree species viz: Aphelenchoides cyrtus and Paraphelenehus acontioides are reported here for the first time from Iran. Paraphelenehus acontioides is separated from the similar species with eight lateral fields and terminal spike or mucro of tail. Aphelenchoides cyrtus is separated from the similar species with four lateral fields, constriction in lip region, number and shape of mucro, length of body and male NEMATODES.

Introduction: Trichostrongyliasis is a zoonotic disease of major public health and socioeconomic importance. Accurate identification of the parasite is the first step in strategic planning for the prevention, control, and treatment of infestation, and for better understanding of the epidemiology of this parasitic disease.Materials and methods: Samples were collected from alimentary tract content of 56 sheep and 53goats in Isfahan and Khorasgan slaughterhouses; identification of Trichostrongylus was conducted based on morphological character and key identification and stained copulatory bursa with azocarmine dye. For genotyping studies, DNA was extracted and the ITS-2 of ribosomal DNA of each species with specific primers was amplified by PCR and restricted with the endonucleases RsaI-Hinfl-DraI. The profiles were visualized in agarose gel under ultraviolet transillumination.Results: Based on the morphological character, four Trichostrongylus species, namely T. axei, T. vitrinus, T. colubriformis, T. probulurus were identified. rDNA-ITS2 fragment size of all species were the same size (about 330bp), however, there were differences between species in their PCR-RFLP patterns. Two fragments were produced with RsaI in all species and were the same size (about 138bp, 190bp). The PCR product T. probulurus with DraI remained .unrestricted. Restriction with DraI produced two fragments in the PCR product of T. axei and T. colubriformis (about 110bp and 215bp, respectively); however, the larger of the two fragments in T. vitrinus is smaller in size than in T. axei and T. colubriformis (about l45bp and 185bp, respectively). Two fragments were produced with Hinfl in T. colubriformis (about 90bp and 238bp, respectively). By contrast, other Trichostrongylus remained unrestricted.Discussion: Based on our results from both morphological and genotyping studies using PCR-RFLP technique, it can be concluded that four species were identified. This study provides a pattern for differentiation of Trichostrongylus.species in Isfahan region using the RsaI-Hinfl-DraI restriction endonucleases.

In a survey conducted to identify terrestrial NEMATODES of Roodghat area, Sufiyan-East Azerbaijan province, Iran, 80 soil samples were collected during 2016 and 2017. The soil samples were processed and the NEMATODES were extracted, killed, fixed, and transferred to anhydrous glycerin as usual. Permanent microscopic slides were prepared from the NEMATODES. Their morphological characteristics and morphometric properties were studied under an optical microscope consisting of a drawing tube. In this study, 35 species belonging to 25 genera (plant parasitic and non-plant parasitic) were identified that among them Axodorylaimellus deviatus (Baqri & Jairajpuri, 1969) Jairajpuri & Ahmad, 1980, Kochinema tenue Argo & Van Den Berg 1971, Laevides laevis (Thorne, 1939) Thorne, 1974, Metaporcelaimus labiatus (de Man, 1880) Andrá ssy, 2001 and Metaxonchium bihariense (Popovici, 1990) Andrá ssy, 1996 were new records for the nematode fauna of Iran and are described here.

In order to identify the plant parasitic NEMATODES (Tylenchida) of the rice fields in Guilan province, about 75 soil and root samples were collected from different fields during 1995 and 1996. The samples were washed and the NEMATODES were extracted by centrifugal suger-floating method. The NEMATODES were fixed and transfered to glycerin by modified seinhorst method (De Grisse, 1969). Then the permanent slides were prepared from NEMATODES including cone-top of cysts and some cross sections of some NEMATODES. The specimens were studied by light microscope.Cysts were also, prepared for scanning electron microscope (SEM) based on HIRSCHMANN and TRIANTAPHYLLOU's method (1979). Ten known plant parasitic NEMATODES belonging to 8 genera were identified including Aphelenchoides besseyi,A. bicaudatus ,Basiria graminophila, Criconemella paragoodeyi, Filenchus facultativus, F. polyhypnus, Helichotylenchus crenacaudatus, H. digitiformis, Heterodera oryzae and Tylenchorhynchus annulatus. F. polyhypnus, H. digitiformis and H. oryzae are new for nematode fauna of Iran as described in the text. In this study the morphological and morphometrical characters of these three species as well as H. digitifomis are described.

Nine species of the family Belonolaimidae were isolated and identified from collected soil samples of lucerne farms in East-Azarbaijan province during 2004-2006. The species were including Amplimerlinius macrurus (Goodey, 1932) Siddiqi, 1976, Geocenamus brevidense (Allen, 1955) Brzeski, 1991, G. nanus (Allen, 1955) Brzeski, 1991, G. pseudobavaricus (Saltukoglu, Geraert & Coomans, 1976) Brzeski, 1991, G. rugosus (Siddiqi, 1963) Brzeski, 1991, Tylenchorhynchus brevilineatus Williams, 1960, T hordei Khan 1972, T. maximus Allen, 1955 and T. usmanensis Khruma & Mahajan, 1987. The species of G. pseudobavaricus, Tylenchorhynchus brevilineatus, T. hordei and T. usmanensis are new records for nematode fauna of Iran. Herein the latter species are described.

Biological control of root knot nematode (Meloidogyne javanica) through Trichoderma viride was investigated in greenhouse conditions. In comparison with the control, different concentrations of the spore of fungus (as treatments) decreased the disease level, egg mass production per plant and mean number of eggs per egg mass (P<0.05). Different concentrations of spore of antagonist decreased the disease level (gall numbers), but in concentration of less than 104 spore/ml there were no significant differences observed among treatments in egg mass production per plant, and at the concentrations of 104-107 spore/ml of the antagonist there were significant differences observed among treatments. There were significant differences among treatments (Trichoderma+ nematode) in egg number per egg mass only at 102 spore/ml of antagonist. Trichoderma viride decreased disease level (gall size means) and mean number of egg mass per plant even after plant inoculation by the nematode. There were significant differences in number of egg mass production per plant and the number of eggs per egg mass at giant cells production stage (4 days after nematode penetration in to the roots), but at the formation of the young adult stage of nematode (15 days after nematode penetration into the roots), only the number of egg mass production per plant was decreased. Maximum level of egg hatching (in control) was observed to be three days after incubation, while in treatments (Trichoderma+ nematode) it was six days after incubation.