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During a survey on the biodiversity of plant-parasitic nematodes in the Misan province, southeast Iraq, a population of Psilenchus hilarulus was discovered around the rhizosphere of okra. The study included the analysis of the morphological and morphometric characteristics of the species that were recovered. These characteristics were then compared to those of other populations that have been reported from other locations. The phylogenetic relationships of the Iraqi population of P. hilarulus with representatives of tylenchid taxa were reconstructed using the partial sequences of the small subunit (SSU), D2-D3 expansion segments of large subunit (LSU), and internal transcribed spacer (ITS) regions of ribosomal DNA, based on Bayesian inference. In the phylogenetic trees inferred from SSU and LSU sequences, the sequences of genus Psilenchus formed a clade separate from the representatives of Tylenchidae and Merliniidae. In the SSU tree, the Iraqi population occupied a placement inside a major clade that includes the sequences assigned to P. hilarulus, P. cucrumerus and Psilenchus sp. In LSU tree, new LSU sequences formed a clade with a major clade that includes sequences assigned to P. hilarulus, P. cucrumerus and P. vinciguerrae. The first ITS sequence of the genus, the ITS rDNA of the Iraqi population of P. hilarulus, was utilized to reconstruct and analyze the corresponding phylogenetic tree. This appears to be the initial documentation of P. hilarulus emerging from Iraq. [ABSTRACT FROM AUTHOR]

Background and Objectives Iran's Khuzestan province ranks first in wheat production. Root-lesion nematodes (RLN) are a group of plant parasitic nematodes that includes several closely related species of economically significant cereals. There have been eight species of RLN recorded for small grains. Four species (P. thornei, P. crenatus, P. neglectus and P. penetrans) are found worldwide, particularly in temperate zones. P. neglectus, P. thornei, P. pseudopratensis and P. penetrans prevalent in Iranian wheat fields. However, there is insufficient information regarding the status of RLN in the province of Khuzestan's cereal fields. The objective of this study was to determine the occurrence, distribution and population density of RLN in wheat and barley fields in Khuzestan province. Material and Methods A survey was conducted over three years (2008-2011), where 169 wheat and 31 barley fields were inspected and sampled in 21 regions during the grain filling and harvesting periods in the Khuzestan province of Iran. A stereomicroscope was used to examine the root tissue of 10 wheat and barley plant samples for disease symptoms. The Whitehead tray method was employed to process 250 cm3 of soil from each collected soil sample. The RLN species were identified using morphological and morphometric characteristics. ArcGIS 9.3 software was utilized to map the distribution of RLN on the map of Khuzestan. Results Results indicated that 37% of wheat fields in the regions of Ahvaz, Andika, Andimeshk, Baghmalek, Behbahan, Dasht-e Azadegan, Dezful, Gotvand, Hoveyzeh, Izeh, Lali, Omidiyeh, Ramshir, Ramhormoz, Shadegan, Shushtar, and Shush were infested with P. thornei and P. neglectus, with mean population densities of 39 and 101 nematodes per gram of root and 250 cm3 of soil, respectively. In addition, 42% of barley fields in Andika, Baghmalek, Izeh, Lali, Omidiyeh, and Ramhormoz were infested with the nematode, with mean population densities of 9 and 72 nematodes per gram of root and 250 cm3 of soil, respectively. The regions with the highest and lowest nematode populations were Shush, Shusthar, Baghmalek, and Hendijan, with densities of 1,334, 904, 11, and 100 per 250 cm3 of soil, respectively. Ten percent of the surviving fields exhibited nematode populations exceeding 1-2 per gram of soil, which is extremely likely to cause cereal crop damage. Discussion Pratylenchus thornei, P. neglectus, and a mix of the two species were observed in 62, 18, and 20% of the surveyed fields in Khuzestan, respectively. In both wheat and barley fields, P. thornei was the dominant species. Globally, P. thornei is deemed more dangerous than P. neglectus. This is the first report of the presence of root lesion nematodes in wheat and barley fields in Khuzestan province, with contamination rates of 37 and 42%, respectively. Disease incidence was higher in irrigated fields than in rain-fed fields, indicating that soil moisture and nutrients positively influence the nematode population. The nematode population density was higher in wheat fields than in barley fields, confirming that barley is a poor host for RLN. The economic damage thresholds for P. thornei and P. neglectus on wheat have been reported to be 1-2 nematodes per gram of soil in various parts of the world. The most important management practice is the use of resistant and tolerant wheat varieties to RLN. [ABSTRACT FROM AUTHOR]

Plant-parasitic nematodes significantly reduce crop production. The stem and bulb nematode (Ditylenchus dipsaci) is one of the important pathogen of several ornamental and field crops including alfalfa. In this study, the reactions of seven alfalfa ecotypes to the nematode were investigated under greenhouse conditions. The experiment was conducted based on completely randomized design with three replicates. The results showed significant differences (P<0.05) among inoculated ecotypes with the nematode in all morphological traits (except of root length) compared to the control. The nematode reproduced in all studied alfalfa ecotypes, but the rate of reproduction was different. The highest reproduction factor (RF) was observed on the ecotype Neishabouri (RF = 7.14) and the lowest on Feiz and Hamedani with reproduction factors of 1.24 and 1.85, respectively. The highest number of the nematode was observed in stems, rhizosphere and buds. The results showed that none of these ecotypes were resistant or tolerant to the stem and bulb nematode. [ABSTRACT FROM AUTHOR]

For identification of nematode species of the genera Ditylenchus and Nothotylenchus, 341 plant and soil samples from farms, orchards and pastures of Fars, Kohgiluye and Boyer-Ahmad, Bushehr and Hormozgan provinces, and 32 samples from Mazandaran, Golestan, Hamadan, Lorestan and Ilam provinces were collected, during 2013-2016. After extraction, killing and fixing, the extracted nematodes were transfered to anhydrous glycerol. Species identification was done using light microscope equipped with digital camera, based on morphometric and morphological characters. The results showed that the genera were existed in 54.7% of the samples. In this study, 12 species of Ditylenchus and five species of Nothotylenchus were identified. D. myceliophagus and D. medicaginis with 38.8% and 38.1% frequency, respectively, and N. geraerti with 60% frequency were the most common species. The species N. basiri, D. geraert and D. solani are new records and were described for the first time from Iran. Moreover, descriptions of N. adasi and N. medians, and the identification key for the Iranian species of the genera Ditylenchus and Nothotylenchus were provided. [ABSTRACT FROM AUTHOR]

In order to identify the plant parasitic nematodes of the families Dolichodoridae and Pratylenchidae (Nematoda: Tylenchomorpha) collected from green space and gardens in Shiraz, Iran, 67 soil and root samples were collected from different localities of the region during 2014-2015. The nematodes were extracted, fixed and transferred to glycerin according to the De Grisse method. The permanent slides were prepared from the extracted nematodes and studied by light microscope. In this study 15 species namely Amplimerlinius globigerus, Merlinius brevidens, Trophurus pakendorfi, Tylenchorhynchus clarus, T. dubius, T. iphilus, T. mashhoodi, T. teeni, Pratylenchus ekrami, P. thornei, P. unzenensis, Zygotylenchus guevarai, Helicotylenchus digonicus, H. pseudorobustus and Rotylenchus buxophilus were identified. The species T. pakendorfi, T. iphilus and P. ekrami as new records of Iranian nematode fauna, along with P. unzenensis are redescribed. [ABSTRACT FROM AUTHOR]

Among plant-parasitic nematodes collected from fields, orchards, meadows and grasslands of the primarily seven southern provinces of the country viz. Fars, Sistan and Baluchistan, Hormozgan, Khuzestan, Kohgiloyeh and Boyer-Ahmad, Kerman and Bushehr; 13 species of the subfamily Telotylenchinae of the genera Bitylenchus, Neodolichorhynchus, Paratrophurus, Trophurus and Tylenchorhynchus were identified morphologically. Three species, N. phaseoli, Trophurus impar and Tylenchorhynchus qasimii, are new records for Iranian nematofauna. Description, morphometric data and line drawings provided for the above three species, as well as three other poorly known telotylenchids in Iran. Furthermore, Tylenchorhynchus variannus considered as a junior synonym of T. clarus here. [ABSTRACT FROM AUTHOR]

Potato cyst nematode, Globodera rostochiensis was reported from potato fields of Bahar County in Hamadan Province in 2008. In order to determine the pathotype of potato cyst nematode, ten populations of potato cyst nematode were collected from different potato fields in Bahar regions. Species identification was based on the morphological and morphometric characters of second stage juveniles and cysts, and by using speciesspecific primers and nucleotide sequences of the D2-D3 expansion segments of the 28S rRNA gene. Four potato cultivars viz Désirée, Marfona, Sante and Agria were used for pathotype determination, in pot experiments. The plants were treated by 6 ± 1 eggs and second stage juveniles and maintained in growth chambers at 18-22°C for three months. Based on the results of resistance assessment and relative susceptibility of the tested cultivars the pathotype of the populations was determined as Ro1. The obtained sequences were compared through BLAST search from the NCBI and the phylogenic tree was depicted. The impact of susceptible cultivars Marfona, Désirée, resistant cultivars sante, and Agria on egg hatching indicated that there is no significant difference among the cultivars in most pot experiments and all the cultivars were placed in the same statistical groups. [ABSTRACT FROM AUTHOR]