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During a survey on the biodiversity of plant-parasitic nematodes in Khuzestan province (southwest Iran), Ditylenchus filimus was discovered in the rhizosphere of date palm. The morphological and morphometric data were provided for the recovered species. The morphological characters of Iranian population are in agreement with the type population and other populations of this species. Molecular phylogenetic analyses of the species with representatives of the family Anguinidae were discussed using partial sequences of the small subunit, D2-D3 expansion segments of the large subunit, and internal transcribed spacer regions of ribosomal DNA (SSU, LSU D2-D3 and ITS rDNA) based on Bayesian inference (BI). To the best of our knowledge, this is the first report of molecular characterization of this species. [ABSTRACT FROM AUTHOR]

The many decades during which the cultivation of Cannabis sativa (hemp) was strongly restricted by law resulted in little research on potential pathogenic nematodes of this increasingly important crop. The primary literature was searched for hemp-nematode papers, resulting in citations from 1890 through 2021. Reports were grouped into two categories: (i) nematodes as phytoparasites of hemp, and (ii) hemp and hemp products and extracts for managing nematode pests. Those genera with the most citations as phytoparasites were Meloidogyne (root-knot nematodes, 20 papers), Pratylenchus (lesion nematodes, 7) and Ditylenchus (stem nematodes, 7). Several Meloidogyne spp. were shown to reproduce on hemp and some field damage has been reported. Experiments with Heterodera humuli (hop cyst nematode) were contradictory. Twenty-three papers have been published on the effects of hemp and hemp products on plant-parasitic, animal-parasitic and microbivorous species. The effects of hemp tissue soil incorporation were studied in five papers; laboratory or glasshouse experiments with aqueous or ethanol extracts of hemp leaves accounted for most of the remainder. Many of these treatments had promising results but no evidence was found of large-scale implementation. The primary literature was also searched for chemistry of C. sativa roots. The most abundant chemicals were classified as phytosterols and triterpenoids. Cannabinoid concentration was frequently reported due to the interest in medicinal C. sativa. Literature on the impact of root-associated chemicals on plant parasitic nematodes was also searched; in cases where there were no reports, impacts on free-living or animal parasitic nematodes were discussed.

The review considers quarantine species and nematode pathotypes potentially dangerous for domestic potato production. Potatoes are affected by more than 30 types of parasitic nematodes, but the review focuses on the most harmful representatives of genera that cause great damage to potato production: Globodera, Ditylenchus, Nacob bus and Meloidogyne. Phytopathological and molecular methods of identification of species and pathotypes and the main achievements in studying the population variability of parasitic potato nematodes were analyzed. It was shown that due to the peculiarities of the life cycle of nematodes and lability of their genomes, the genetic variability of these organisms is very high, which creates a threat of forming new pathogenic genotypes of the parasites. The information about the intra- and interpopulation variability of nematodes is important for studying the ways of introduction and distribution of separate species, as well as for searching for the correlations of molecular markers with the pathotype. Phylogenetic studies based on modern data on genetic variability of populations have allowed to reveal species complexes in Globodera pallida (Stone) Behrens and Nacobbus aberrans (Thorne) Thorne & Allen (sensu lato), including cryptic species. The main components of successful protection preventing a wide distribution of parasitic nematodes are quarantine measures, agricultural techniques, biological methods of protection and cultivation of resistant cultivars. Special attention in the review is paid to the breeding of potato cultivars with durable resistance to various nematode pathotypes, because the cultivation of such varieties is the most ecologically safe and economically advantageous way to prevent epiphytoties. Currently, significant progress has been made in the genetic protection of potato cultivars, especially against cyst-forming nematodes. The review provides data on sources of potato resistance to parasitic nematodes identified in collections of wild and cultivated species. Data on identified R-gens and QTL of resistance that have been introduced into breeding varieties using different methods and approaches are analyzed. The literature data on the study of structural and functional organization of genes for resistance to potato cyst nematodes are given. The results of molecular research on revealing the polymorphisms of loci involved in the control of resistance to cyst and gall nematodes, the development of molecular markers of certain genes and their use in marker-assisted selection for developing of new resistant cultivars, including those with group resistance, are considered.

به منظور شناسایی نماتدهای مرتبط با جنگل‏ های بلوط شهرستان خرم‏ آباد طی سال‏های 1393-1394، 82 نمونه از خاک اطراف ریشه و پوست درختان بلوط شهرستان خرم ‏آباد جمع‏آوری شد. پس از استخراج، کشتن و تثبیت نماتدها شناسایی گونه ‏ها براساس ویژگی‏ های ریخت‏ شناختی و ریخت‏ سنجی با استفاده از میکروسکوپ نوری مجهز به دوربین دیجیتالی انجام گرفت. در این بررسی 26 گونه از فوق بالا خانواده‏ی Tylenchomorpha و خانواده Longidoridae شناسایی شدند. نام این گونه‌ها به شرح زیر است: Aphelenchus avenae, Laimaphelenchus australis L. penardi, Paraphelenchus amblyurus, Aprutides guidetti, Ditylenchus medicaginis, D. anchilisposomus,D. parvus,Mesocriconema antipolitanum, Amplimerlinius globigerus, Scutylenchus rugosus, Merlinius brevidens, M. nanus, Trophurus ussuriensis, Helicotylenchus digonicus, H. exallus, H. vulgaris, Pratylenchoides ritteri, Pratylenchus neglectus, P. thornei, Zygotylenchus guevarai,Boleodorus thylactus, Discotylenchus sp, Psilenchus hilarulus, Paratylenchus similis, Xiphinema index از بین گونه‏ های شناسایی شده 19 گونه برای اولین ‏بار از ریزوسفر درختان بلوط ایران گزارش می ‏شوند. در طی این تحقیق همچنین گونه ‏های Laimaphelenchus australis و جمعیت نر گونه L. penardi از پوست تنه درختان جمع‏ آوری شدند و برای اولین ‏بار از ایران گزارش می‏ شوند، حضور این نماتدهای قارچ‏ خوار می‏ تواند بر تعادل قارچ‏ های اندوفیتی تأثیر بگذارد که مهمترین عوامل تعیین کننده سلامت ریشه، پوست و تنه گیاهان هستند. در این مقاله توصیف کامل این دو گونه همراه با گونه ‏ی Ditylenchus anchilisposomus که برای اولین ‏بار به طور کامل شرح داده می‏ شود، ارائه گردیده است.

Members of the family Tylenchidae are highly abundant in soil habitats, including agricultural settings, where they play key ecological roles. In the present study, we identified three Tylenchidae species, namely Basiria bhabi, Coslenchus acceptus, and Filenchus vulgaris, using integrative taxonomy. The detailed morphological and morphometric characteristics, distribution, and host associations of each species were also discussed. Phylogenetic analyses of these populations with other Tylenchidae nematodes indicated the presence of divergent lineages in Filenchus and Basiria, whereas Coslenchus appeared to be a monophyletic genus. Herein, we aim to grow awareness about this common but least studied group of nematodes. The species reported in this study are new records for Canada, revealing that the identified nematode diversity in our cultivated areas is relatively underrepresented. Our analyses also provided greater taxonomic resolution and captured rare taxa that might have been missed or misidentified in prior nematode inventory surveys. These findings will add to our understanding of the nematofauna of southern Alberta, thereby providing a more complete picture of existing nematode diversity present in the fields of this highly cultivated region. [ABSTRACT FROM AUTHOR]

Hybrids and cultivars of single type tuberose was evaluated to fulfill the need to develop new hybrids as demanded by commercial growers. Evaluation of fifteen genotypes showed significant variation in growth, floral and bulb characters. Cultivar Arka Prajwal was significantly superior over all genotypes, which recorded least number of days for opening of 1st floret (78.55 days) with maximum diameter of spike (1.18 cm), length of floret (6.05 cm), weight of individual floret (3.12 g) and weight of spike (121.43 g).The hybrid genotype L1P4 (Variegated X Phule Rajani) was observed to be superior in terms of rachis length (39.78 cm), inter-nodal length (7.25 cm), length of bulb (8.09 cm), diameter of bulb (3.76 cm) and diameter of bulb-lets (1.85 cm). Among the hybrid genotypes L1P4 also recorded maximum plant height (116.39 cm), spike length (109.58 cm), weight of cut spike (105.08 g) and vase life (11.00 days). However, it was foundto be at par for number of florets per spike (57.25), length of floret (5.92 cm) and number of spikes per clump (10.14) with all other cultivars and hybrids tested. From the overall performance, it was found that the cultivar Arka Prajwal was the best. Genotype L1P4 found promising for loose as well as cut flower production because of its number of florets, inter-nodal length and spikes per clump which are important characters considering loose flower for taking maximum number of pickings. However, characters such as rachis length, spike length, vase life and weight of spike which are imperative for cut flowers are also noted superior in genotype L1P4. [ABSTRACT FROM AUTHOR]

Summary: Bark beetles (Curculionidae: Scolytinae) have a significant economic impact on forest stands and agricultural settings in Israel. We focus on nematodes associated with bark beetles collected from different host plants attacked by Scolytinae. The sampling was conducted in forest plantations and fruit tree orchards in several areas in Israel. A total of 430 beetle specimens of eight species were examined for the presence of nematodes. Fifteen nematode species were detected and identified based on molecular and morphological characteristics. Among the examined scolytids, the pine bark beetle, Orthotomicus erosus , the most widely distributed and frequently occurring species in Israel, was accompanied by the highest nematode diversity, with 11 species recovered. Nematode associations with the almond bark beetle (Scolytus amygdali), the olive bark beetle (Phloeotribus scarabaeoides) and the fig bark beetle (Hypoborus ficus) were recorded for the first time. Our study thus supplies novel information on scolytid-associated nematodes in Israel. [ABSTRACT FROM AUTHOR]

Summary: Litylenchus crenatae n. sp., isolated from leaf galls of Fagus crenata from Japan, is described and figured. The new species is characterised by its dimorphism in adult females, six (or more) lateral lines, a more or less pointed tail tip in both sexes, male bursa arising posteriorly and reaching to near tail tip, presence of a quadricolumella and a post-uterine sac in females. Litylenchus crenatae n. sp. is distinguished from its only congener, L. coprosma , by the number of lateral lines, six or more vs four; the lip morphology, offset with very shallow constriction or dome-shaped without clear constriction vs clearly offset; tail tip morphology, more or less pointed vs blunt; and structure of the median bulb, weakly muscular with a clear valve vs not muscular with an obscure valve. The molecular phylogenetic analysis confirms that the new species is close to, but clearly different from, L. coprosma. [ABSTRACT FROM AUTHOR]

During a survey of soil nematodes in Iran, some known species belonging to the genus Ditylenchus were recovered from the rhizosphere of alfalfa: Ditylenchus acutus, Ditylenchus myceliophagus and Ditylenchus terricolus. Measurements and illustrations are provided for these species. A molecular study of the 28S rDNA region of the Ditylenchus species from Iran placed them in separate clades. Phylogenetic analysis indicates that Ditylenchus destructor is a monophyletic taxon. In addition, D. acutus places together with D. destructor, Ditylenchus arachis, Ditylenchus sarvarae, Ditylenchus persicus and Ditylenchus halictus in a clade. While D. myceliophagus and D. terricolus form a separate clade. Phylogenetic positions and morphometrics of D. acutus, D. myceliophagus and D. terricolus are given. [ABSTRACT FROM AUTHOR]

Despite their physiological differences, sedentary and migratory plant-parasitic nematodes (PPNs) share several commonalities. Functional characterization studies of key effectors and their targets identified in sedentary phytonematodes are broadly applied to migratory PPNs, generalizing parasitism mechanisms existing in distinct lifestyles. Despite their economic significance, host–pathogen interaction studies of migratory endoparasitic nematodes are limited; they have received little attention when compared to their sedentary counterparts. Because several migratory PPNs form disease complexes with other plant-pathogens, it is important to understand multiple factors regulating their feeding behavior and lifecycle. Here, we provide current insights into the biology, parasitism mechanism, and management strategies of the four-key migratory endoparasitic PPN genera, namely Pratylenchus, Radopholus, Ditylenchus, and Bursaphelenchus. Although this review focuses on these four genera, many facets of feeding mechanisms and management are common across all migratory PPNs and hence can be applied across a broad genera of migratory phytonematodes.

During a survey of soil nematodes in Iran, some known species belonging to the genus Ditylenchus were recovered from the rhizosphere of alfalfa: Ditylenchus acutus, Ditylenchus myceliophagus and Ditylenchus terricolus. Measurements and illustrations are provided for these species. A molecular study of the 28S rDNA region of the Ditylenchus species from Iran placed them in separate clades. Phylogenetic analysis indicates that Ditylenchus destructor is a monophyletic taxon. In addition, D. acutus places together with D. destructor, Ditylenchus arachis, Ditylenchus sarvarae, Ditylenchus persicus and Ditylenchus halictus in a clade. While D. myceliophagus and D. terricolus form a separate clade. Phylogenetic positions and morphometrics of D. acutus, D. myceliophagus and D. terricolus are given.

The antagonistic activities of essential oils of Ajania potaninii and A. fruticulosa against Ditylenchus destructor were determined by the liquid soak method in 96-well microplates. The main constituents of A. potaninii essential oil were 1,8-cineole (22.19%), (+)-camphor (12.84%), (−)-verbenol (13.84%) and borneol (12.67%). The results showed that the essential oils of A. fruticulosa (EC50 = 0.17 mg ml−1) and A. potaninii (EC50 = 0.27 mg ml−1) have antagonistic activity against D. destructor. The results also showed that 1,8-cineole (EC50 = 0.49 mg ml−1), myrtenol (EC50 = 0.40 mg ml−1) (A. fruticulosa) and (−)-verbenol (EC50 = 1.09 mg ml−1) (A. potaninii) have antagonistic activity. 1,8-Cineole is a key element affecting the antagonistic activity that was found in both essential oils. Several main constituents found in the essential oils had antagonistic effects against D. destructor. These results provide the basis for future development and utilisation of a substance to control D. destructor. [ABSTRACT FROM AUTHOR]

The 18S small subunit (SSU) ribosomal DNA sequence is one of the most useful molecular loci for identification and phylogeny reconstruction of agriculturally important nematodes. Various pairs of universal primers have been developed in the past to amplify short and long nematode sequences. However, certain nematode taxa were not readily amplified and/or sequenced with the existing primer tools. Frequently, the center region of a roughly 1,000 nucleotide segment would be lost. Therefore new primers were developed based on a very large 276 taxon alignment of 124 agriculturally important nematode species, and tested on problematic nematode taxa such as Aphelenchoides, Bursaphelenchus, Ditylenchus, and Panagrolaimus. New primers and protocols are provided for successful generation of sequences useful in future investigations of nematode systematics. [ABSTRACT FROM AUTHOR]

Abstract: Alfalfa is a major cash crop in the western United States, where fields that are infested with the alfalfa stem nematode (Ditylenchus dipsaci) can be found. With no nematicides available to control alfalfa stem nematode spread, growers can use nematode resistant varieties of alfalfa to manage nematode populations in a field. A deterministic, discrete‐time, host‐parasite model is presented that describes the spread of alfalfa stem nematodes on resistant hosts that were fit to experimental data obtained in Weber County, Utah. Numerical results obtained from simulations with the model are used to compare how varying levels of resistance can affect harvest yield. Recommendations for Resource Managers: Alfalfa stem nematodes have a significant impact on alfalfa production. Nematode resistant varieties of alfalfa can be used to lessen the impact of nematodes on the alfalfa. This discrete deterministic model is used to determine how different levels of nematode resistance in these varieties will affect harvest yield and nematode populations in the field. Alfalfa varieties that have a resistance to nematodes can improve yield and lower the nematode population in an infested field. [ABSTRACT FROM AUTHOR]

Ditylenchus weischeri that parasitizes the weed Cirsium arvense (L.) Scop., 1772, (creeping thistle) was described in 2011 from Russia based on their morphology, ITS-RFLP analysis, and Hsp90 gene sequence of a few individuals and one field collection of the plant. More recently, we found C. arvense parasitized by D. weischeri in the Prairie Provinces of Canada. Plant host preference for D. weischeri was also distinct from D. dipsaci (Kühn) Filipjev, 1936. In the current study, a comprehensive molecular analysis of many D. weischeri specimens from Canada is presented. Individuals from 41C. arvense or yellow pea grain samples with seeds of C. arvense from the Prairie Provinces were sequenced for the internal transcribed spacer (ITS rDNA), large subunit (LSU) D2D3 28S rDNA, partial segment of small subunit (SSU) 18S rDNA, and the heat shock protein Hsp90 gene. The analysis also included D. weischeri individuals from C. arvense from Russia and garlic with D. dipsaci from the Provinces of Ontario and Quebec in Canada. Available sequence data of Ditylenchus species retrieved from GenBank were used to phylogenetically position this species within the genus Ditylenchus. In all studied genes, several single-nucleotide polymorphisms between the Canadian D. weischeri and both Russian haplotype and individuals of D. weischeri from C. arvense from Russia were found. The sequences of ITS rDNA, LSU D2D3 28S rDNA, and Hsp90 were used to construct separate dendrograms. For each of the three genes examined, D. weischeri was grouped separately from the other Ditylenchus. Ditylenchus samples from C. arvense was positioned to a single clade such as D. weischeri and distinct from D. dipsaci. With past reports of plant host preference and morphology, the results of this study provide further evidence for the fact that D. weischeri is distinct to be separated from D. dipsaci. Furthermore, minor differences in molecular divergence and morphology to the Russian haplotype and limited symptoms of disease on C. arvense in Prairie Canada suggest the Canadian and Russian populations of D. weischeri may be diverging. [ABSTRACT FROM AUTHOR]

Rice, pulses and oilseed crops are major exporting crops in Myanmar. Many plant-parasitic nematodes, such as Meloidogyne incognita, M. javanica, M. graminicola, Ditylenchus angustus, Hirschmanniella oryzae, Heterodera cajani and Pratylenchus spp., have been detected in these crops in different cropping patterns and are considered one of the reasons for their low yields. Previous surveys have shown potential impact to yield losses in the crops. This Forum article provides collective information on species of the major plant-parasitic nematodes, possible damage and available control measures to such economically important crops in Myanmar. [ABSTRACT FROM AUTHOR]

Plant-parasitic nematodes (PPNs) interact with plants in different ways, for example, through subtle feeding behavior, migrating destructively through infected tissues, or acting as virus-vectors for nepoviruses. They are all obligate biotrophic parasites as they derive their nutrients from living cells which they modify using pharyngeal gland secretions prior to food ingestion. Some of them can also shield themselves against plant defenses to sustain a relatively long lasting interaction while feeding. This paper is centered on cell types or organs that are newly induced in plants during PPN parasitism, including recent approaches to their study based on molecular biology combined with cell biology-histopathology. This issue has already been reviewed extensively for major PPNs (i.e., root-knot or cyst nematodes), but not for other genera (viz. Nacobbus aberrans, Rotylenchulus spp.). PPNs have evolved with plants and this co-evolution process has allowed the induction of new types of plant cells necessary for their parasitism. There are four basic types of feeding cells: (i) non-hypertrophied nurse cells; (ii) single giant cells; (iii) syncytia; and (iv) coenocytes. Variations in the structure of these cells within each group are also present between some genera depending on the nematode species viz. Meloidogyne or Rotylenchulus. This variability of feeding sites may be related in some way to PPN life style (migratory ectoparasites, sedentary ectoparasites, migratory ecto-endoparasites, migratory endoparasites, or sedentary endoparasites). Apart from their co-evolution with plants, the response of plant cells and roots are closely related to feeding behavior, the anatomy of the nematode (mainly stylet size, which could reach different types of cells in the plant), and the secretory fluids produced in the pharyngeal glands. These secretory fluids are injected through the stylet into perforated cells where they modify plant cytoplasm prior to food removal. Some species do not produce specialized feeding sites (viz. Ditylenchus, Subanguina), but may develop a specialized modification of the root system (e.g., unspecialized root galls or a profusion of roots). This review introduces new data on cell types and plant organs stimulated by PPNs using sources varying from traditional histopathology to new holistic methodologies.

Plant-parasitic nematodes (PPNs) interact with plants in different ways, for example, through subtle feeding behavior, migrating destructively through infected tissues, or acting as virus-vectors for nepoviruses. They are all obligate biotrophic parasites as they derive their nutrients from living cells which they modify using pharyngeal gland secretions prior to food ingestion. Some of them can also shield themselves against plant defenses to sustain a relatively long lasting interaction while feeding. This paper is centered on cell types or organs that are newly induced in plants during PPN parasitism, including recent approaches to their study based onmolecular biology combined with cell biology-histopathology. This issue has already been reviewed extensively for major PPNs (i.e., root-knot or cyst nematodes), but not for other genera (viz. Nacobbus aberrans, Rotylenchulus spp.). PPNs have evolved with plants and this co-evolution process has allowed the induction of new types of plant cells necessary for their parasitism. There are four basic types of feeding cells: (i) non-hypertrophied nurse cells; (ii) single giant cells; (iii) syncytia; and (iv) coenocytes. Variations in the structure of these cells within each group are also present between some genera depending on the nematode species viz. Meloidogyne or Rotylenchulus. This variability of feeding sites may be related in some way to PPN life style (migratory ectoparasites, sedentary ectoparasites, migratory ecto-endoparasites, migratory endoparasites, or sedentary endoparasites). Apart from their co-evolution with plants, the response of plant cells and roots are closely related to feeding behavior, the anatomy of the nematode (mainly stylet size, which could reach different types of cells in the plant), and the secretory fluids produced in the pharyngeal glands. These secretory fluids are injected through the stylet into perforated cells where they modify plant cytoplasm prior to food removal. Some species do not produce specialized feeding sites (viz. Ditylenchus, Subanguina), but may develop a specialized modification of the root system (e.g., unspecialized root galls or a profusion of roots). This review introduces new data on cell types and plant organs stimulated by PPNs using sources varying from traditional histopathology to new holistic methodologies. [ABSTRACT FROM AUTHOR]

Ditylenchus weischeri was recently reported in the provinces of Manitoba and Saskatchewan, Canada. Populations of D. weischeri from creeping thistle (Cirsium arvense L.) in Manitoba and D. dipsaci from garlic (Allium cepa L.) in Ontario were examined for their potential to grow on callused carrot (Daucus carota subsp. sativus) disks, alfalfa (Medicago sativa L.) and creeping thistle callus tissues, and pure cultures of eight fungal species, Botrytis cinerea, Fusarium solani, Rhizoctonia solani, Verticillium dahliae, Sclerotinia sclerotiorum, Cladosporium cucumerinum, Colletotrichum gloeosporioides, and Chaetomium spp. Ditylenchus weischeri and D. dipsaci could not be reared on any of the fungal isolates nor in the callus tissues of creeping thistle. In contrast to D. weischeri, D. dipsaci was successfully reared on the alfalfa callus tissue. On the callused carrot disks, with no media, an increase of 54 and 244 times the initial density of 80 nematodes was obtained for D. weischeri and D. dipsaci, respectively. Monoxenic rearing was performed using callused carrot disks to provide sufficient D. weischeri inoculum for the microplot study. The effect of D. weischeri on yellow pea varieties Agassiz and Bronco was determined in a microplot trial using initial densities of 0, 100, 200, 400, 800, 1600, and 3200 nematodes/plant. While it had no impact on pea grain yield, D. weischeri slightly reduced plant height, aboveground biomass, and pod length at the population densities of 1600 and 3200 nematodes/plant. The final population densities at harvest were not significantly different from the initial densities indicating the pea varieties were poor hosts to D. weischeri. The results of the present study indicate that D. weischeri is unlikely to be a pest of yellow pea for weather conditions of the Canadian Prairies. [ABSTRACT FROM AUTHOR]

The family Tylenchidae is phylogenetically important to understanding early-branching Tylenchomorpha and to assess soil ecosystems. In this study, we focus on Malenchus and Filenchus as representatives of the Tylenchidae. Samples collected worldwide result in 58 new sequences, and light microscopy and transmission electron microscopy provide details on morphological features. For the first time, comprehensive morphological data are evaluated in the context of a molecular framework, thus highlighting the phylogenetic and evolutionary complexity of this structurally minimalistic group. Results show that the genus Filenchus is polyphyletic in both the 18S and 28S rDNA phylogeny, while Malenchus is polyphyletic and monophyletic in the 28S rDNA and the 18S rDNA, respectively. Ultrastructural study demonstrates specific aspects of lateral cuticular incisures, cuticular layering and the amphideal fovea are surprisingly congruent with the obtained molecular phylogenies, while classical characteristics such as cuticle annulations are evolutionary highly plastic and mosaic in distribution. The study also reveals the shortage of D2/D3 domain in 28S rDNA as a phylogenetic marker for early-branching Tylenchomorpha. [ABSTRACT FROM AUTHOR]

Root and soil samples were collected and examined from faba bean (Vicia fabaL.) fields in Khuzestan province, southwestern Iran. Seven nematode species were identified as follows:Ditylenchus dipsaci,Ditylenchus medicaginis,Geocenamus bavaricus,Geocenamus brevidens,Geocenamus nanus,Geocenamus nothusandHoplolaimus seinhorsti. Morphometrics and light micrography were provided for the studied species and their differences with those given in their original descriptions were discussed. Populations varied in their frequency and distribution among surveyed faba bean fields butG. brevidenswas the most commonly observed species. This is new record ofD. dipsaci,D. medicaginis,G. bavaricus, G. nanusandG. nothusfor nematodes fauna in Khuzestan province.G. bavaricus, G. nanus,G. nothusandH. seinhorstiare reported for the first time in association with faba bean in Iran. This is the first report ofG. brevidensandG. nanusfrom roots of faba bean. [ABSTRACT FROM PUBLISHER]

A great number of spring garlic populations are present in Serbia. It is a very heterogeneous biological material. To date, it has been little studied. Therefore, the aim was to study its production and chemical characteristics. Eighteen populations of spring garlic were examined. Most of the production of this garlic in Serbia is based on them. They were examined in Zminjak, which is located in the central Mačva (Serbia). The method of field experiments was used. The research lasted for three years. The results comprise two groups of parameters. The first group contains the results which show the most important productive characteristics (weight of bulb, number of cloves per bulb, bulb yield). The second group consists of the parameters for chemical characteristics of the investigated populations (dry matter, etheric oil, and alliin). In this case, the populations demonstrated a significant influence, and their stability was also very conspicuous. Most of the investigated populations of spring garlic can serve as a good resultant material for obtaining new cultivars. The populations can be classified as follows: SG-18, SG-25, SG-28, SG-16, SG-29 (yield), SG-21, SG-26 (technological quality) and SG-29, SG-18, SG-16 (foodstuff and pharmaceutical quality). They can remain as populations, but it would be significantly better to create new cultivars by using them. [ABSTRACT FROM AUTHOR]

A new species of the genus Ditylenchus, D. persicus n. sp., was collected around the roots of grapevine and is described and illustrated herein based on morphological and molecular studies. The new species is characterised by a body length of 783 (635-928) µm and 689 (670-715) µm in female and male, respectively, delicate stylet 6.2 (5.0-7.0) µm long, six lines in the lateral field, median bulb of pharynx well developed, muscular with crescentic valve, basal pharyngeal bulb pyriform with 10 (8-13) µm long stem extending into intestine, post-vulval uterine sac relatively short, 16 (14-18) µm long, female and male tail elongate-conoid with finely rounded terminus, and bursa covering 65-80% of male tail length. Morphologically, D. persicus n. sp. appears closer to five known species of the genus, namely: D. arachis, D. caudatus, D. clarus, D. myceliophagus and D. nanus. The results of phylogenetic analyses based on sequences of D2-D3 expansion region of 28S rRNA, ITS and partial 18S rRNA genes confirmed the close molecular relationship between D. persicus n. sp. and other Ditylenchus species such as D. myceliophagus, D. africanus, D. arachis, D. destructor and D. halictus. [ABSTRACT FROM AUTHOR]

The genus Ditylenchus consists of more than 60 species, some of which are plant parasites. In this paper we report on Ditylenchus laurae sp. n. from Poland, a new species associated with the aquatic plant, Potamogeton perfoliatus L. Ditylenchus laurae sp. n. is characterised by a long and slender body with L = 1881 (1523-2095) µm and 1875 (1690-2089) µm, a = 88.8 (72.5-102.5) and 89.7 (71.9-97.9), stylet length = 10.8 (9.6-12.1) µm and 8.3 (7.7-9.0) µm, tail length = 117.2 (103.5-126.7) µm and 102.4 (98.3-113.6) µm in females and males, respectively; four incisures, rounded stylet knobs, long basal bulb (about ten times as long as wide), post-vulval uterine sac from 4.3-5.6 vulval body diam. long, and mucronate tail. Characterisation using the ITS rRNA, COI and hsp90 gene sequences was conducted and a phylogenetic analyses revealed that D. laurae sp. n. belongs to the D. dipsaci complex. [ABSTRACT FROM AUTHOR]

The ability of the recently described stem nematode of creeping thistle (Cirsium arvense L.), Ditylenchus weischeri, to develop on and parasitize yellow pea (Pisum sativum L.) is uncertain. The current study examined nematode life-stage progression and generation time on yellow pea as affected by temperature with the related pest, D. dipsaci, used as a positive control. Relationships for body length of the two nematode species and life stage were unaffected by rearing on plant hosts compared with carrot disks. Then plant-reared J4 individuals of both nematode species were used to determine the effect of temperature (17, 22, and 27°C) on lifestage progression and minimum generation time with yellow pea. At 17 and 22°C, D. weischeri J4 individuals progressed to only the adult stage whereas, at 27°C, the minimum generation time from J4 to J4 was 30 days or 720 growing degree-days. The minimum generation time for D. dipsaci was 24, 18, and 22 days or 336, 342, and 528 growing degree-days at 17, 22, and 27°C. respectively. The results indicate that development of D. weischeri is temperature dependent and reproduction is unlikely on yellow pea in the Canadian Prairies, where mean daily air temperatures of 27°C are rare and not sustained. [ABSTRACT FROM AUTHOR]

The majority of gall-inducing nematodes lives in the soil, and induces galls on roots. Nevertheless, some nematodes are able to climb up the stems and induce galls on aerial plant organs. This is the case of Ditylenchus gallaeformans (Oliveira et al., 2013), which induces galls on the inflorescences of Miconia albicans (Sw.) Steud. (1841) and Miconia ibaguensis (Bonpl.) Triana (1871) (Melastomataceae). Under the influence of D. gallaeformans , the flowers of M. albicans and M. ibaguensis do not differentiate in situ . Instead of flowers, the axes of the galled inflorescences are surrounded by emergences with nutritive tissues lining the larval chambers. The nutritive tissues are meristem-like, but distinct from other galls, they have a promeristematic capability. In other words, the nutritive tissues of these galls have totipotent cells, originating new covering emergences with dermal, ground and vascular tissues. Therefore, these galls have an indeterminate growth, which is a novelty for galls in general. Additionally, D. gallaeformans induces a long-distance impact on fruits, which have increased number of carpels. Such long-distance effects indicate that D. gallaeformans is a peculiar colonial parasite, which may compensate the damages of gall inducing mechanisms by favoring, at least partially, its host plant fitness. The number of carpels is a conservative character in most plant species, and the promeristems are maintained only in apical and lateral buds of normal plants. However, D. gallaeformans is capable of manipulating these conservative features in its host plants, and the signaling factors involved in these interactions deserves special attention. [ABSTRACT FROM AUTHOR]

O objetivo deste trabalho foi identificar e quantificar a nematofauna fitopatogênica de sementes de forrageiras, destinadas aos mercados interno e externo. Examinaram-se sementes de Brachiaria brizantha (cvs. Marandu e Xaraés), B. decumbens cv. Basilisk, Panicum maximum (cvs. Massai, Mombaça e Tanzânia) e Stylosanthes capitata e S. macrocephala, componentes da cultivar Estilosantes Campo Grande. As extrações foram realizadas por flotação centrífuga, em solução de sacarose com caulim. Nas gramíneas, encontraram-se os gêneros Aphelenchoides e Ditylenchus. O maior número de espécimes de Aphelenchoides spp. foi observado nas sementes de 'Marandu', e, em seguida, nas sementes de 'Xaraés', 'Basilisk' e 'Tanzânia'. Quanto à densidade populacional de Ditylenchus spp., os maiores valores foram observados nas sementes de 'Marandu', 'Xaraés' e 'Basilisk'. Os resultados sugerem que pelo menos duas espécies de Aphelenchoides e Ditylenchus estão associadas às sementes de gramíneas forrageiras, destinadas ao mercado interno. Fitonematóides não são detectados em sementes de 'Estilosantes Campo Grande', tampouco nas cultivares Marandu, Mombaça e Tanzânia, destinadas à exportação.The objective of this work was to identify and quantify the phytopathogenic nematofauna of forage seeds destined for internal and external markets. Seeds of Brachiaria brizantha (cvs. Marandu and Xaraés), B. decumbens cv. Basilisk, Panicum maximum (cvs. Massai, Mombaça and Tanzania), and Stylosanthes capitata and S. macrocephala, components of cv. Estilosantes Campo Grande, were examined. The extractions were made by centrifugal flotation in solution of sucrose with kaolin. Aphelenchoides and Ditylenchus genera were detected in forage grasses. The highest number of Aphelenchoides spp. specimens was observed in seeds of cv. Marandu, followed by seeds of cvs. Xaraés, Basilisk, and Tanzania. Regarding Ditylenchus spp. population density, higher values were detected in seeds of cvs. Marandu, Xaraés, and Basilisk. The results suggest that two or more species of Aphelenchoides and Ditylenchus are associated to forage grass seeds destined for Brazilian market. Phytopathogenic nematodes are not detected in Estilosantes Campo Grande seeds, neither in seeds of cvs. Marandu, Mombaça and Tanzania destined for exportation.

Plant-parasitic nematodes were found in 4 of the 12 clades of phylum Nematoda. These nematodes in different clades may have originated independently from their free-living fungivorous ancestors. However, the exact evolutionary process of these parasites is unclear. Here, we sequenced the genome sequence of a migratory plant nematode, Ditylenchus destructor. We performed comparative genomics among the free-living nematode, Caenorhabditis elegans and all the plant nematodes with genome sequences available. We found that, compared with C. elegans, the core developmental control processes underwent heavy reduction, though most signal transduction pathways were conserved. We also found D. destructor contained more homologies of the key genes in the above processes than the other plant nematodes. We suggest that Ditylenchus spp. may be an intermediate evolutionary history stage from free-living nematodes that feed on fungi to obligate plantparasitic nematodes. Based on the facts that D. destructor can feed on fungi and has a relatively short life cycle, and that it has similar features to both C. elegans and sedentary plant-parasitic nematodes from clade 12, we propose it as a new model to study the biology, biocontrol of plant nematodes and the interaction between nematodes and plants. [ABSTRACT FROM AUTHOR]

Morphological and molecular analyses of a stem nematode causing a severe disease on infected sowthistle (Sonchus bulbosus) plants, involving the formation of gall-like structures on infected leaves and stems, have led to the description of a new species named Ditylenchus oncogenus n. sp. Morphologically, the new species is characterized by a medium to large body size (all adults more than 1 mm in length); a delicate stylet (9.0–11.0 μm long) with minute, rounded knobs; a long post-vulval uterine sac (c. 65% of the vulva–anus distance); six incisures at the lateral fields and characteristic D. destructor-pattern of spicules (with pronounced ventral tumulus and anteriorly pointed, less sclerotized, cuticle parts present within the lamina). The results of molecular analysis of rRNA gene sequences, including the D2–D3 expansion regions of 28S rRNA, internal transcribed spacer (ITS) rRNA, partial 18S rRNA gene, the protein-coding mitochondrial gene, cytochrome oxidase c subunit I (COI), and the heat-shock protein 90 (hsp90) gene, support the new species status. The results of a host-suitability test indicated that the new species does not parasitize potato (Solanum tuberosum) tubers and broad bean (Vicia faba) seedlings. Histopathological observations on naturally infected sowthistle tissues revealed that D. oncogenus n. sp. causes floral stem neoplasia and midrib leaf gall formation on the type, and to date only known, host. The galls were characterized by extensive hyperplasia, where several necrotic cells in the neoplasic area were directly damaged by feeding of the nematode, whereas a number of adjacent cells showed typical cytological changes, such as granulated cytoplasm with hypertrophied nuclei and nucleoli. [ABSTRACT FROM AUTHOR]

The genus Ditylenchus has been divided into 2 groups: the D. triformis-group, and the D. dipsaci-group based on morphological and biological characters. A total of 18 populations belong to 5 species of Ditylenchus was studied: D. africanus, D. destructor, D. myceliophagus and dipsaci, D. weischeri, the first 3 belong to the D. triformis-group, the last 2 the D. dipsaci-group. The species of D. triformis-group were cultured on fungi, while the species from D. dispaci-group cultured on excised roots of plant hosts in petri dish. DNA sequences of regions of the nuclear ribosomal first internal transcribed spacer (ITS1) and the small subunit 18S were PCR amplified, sequenced and the phylogenetic analyses also including the sequences of the closely related species from the GenBank. The randomly amplified polymorphisms of genomic DNA (RAPD) were also generated. Two clusters or clades corresponding to the 2 groups were consistently observed with significant statistical support from the 3 datasets. The phylogenetic analysis also revealed that the genus is paraphyletic, separating the 2 groups by species of Anguina and Subanguina. [ABSTRACT FROM AUTHOR]

The rice stem nematode Ditylenchus angustus causes “Ufra” disease in rice resulting in substantial yield losses. Although it is predominant in deep water rice in South and Southeast Asia, this nematode also infects irrigated and rainfed low land rice. This study evaluated rice genotypes (irrigated, rainfed, deep water and landraces) for resistance to the Bangladeshi population of D. angustus . The experiment was executed using artificial inoculation, in both rainfed and irrigated ecosystems. The rice varieties were first scored at 28 days post inoculation (dpi), and ranked based on the postinfectional reactions and severity of symptoms on a 0–16 rating scale. The susceptibility of the varieties was also evaluated at a later time point, i.e. 55 dpi, based on the percentage of tiller infections, using a disease index scoring system ranging from 0 to 9. Both screening methods showed a similar ranking of the varieties for susceptibility/resistance against this nematode. The experiment was initially conducted in plastic pots, and the promising varieties were analyzed further in field conditions. Out of the 85 varieties, one landrace named ‘Manikpukha’ proved to be highly resistant, while 6 other varieties showed resistance and 13 varieties showed moderately resistant responses under both pot and field conditions. The promising varieties found in the present investigation can be used in rice breeding programs as well as for further detailed studies to develop a sustainable ufra management strategy. [ABSTRACT FROM AUTHOR]

The article offers information on the subspecies Allium phanerantherum of the family Amaryllidaceae which producing an involucrelike structure at the base of umbel; pedicels scabrid at the apex; bulblets few, attached to the bulb from Turkey. It mentions that subspecies grows on dry hillsides, on limestone and serpentine and the spathe and bracteole morphology provide some of the most important diagnostic characters for the differentiation of taxa.

Published data on the presence or absence of phasmids in males of Heteroderidae species are compiled and critically reviewed. Based mainly on results of previous SEM studies and complemented by light microscopy using DIC optics, the conclusion is drawn that male phasmids appear to be absent in all species of the genera assigned to the subfamilies Heteroderinae and Ataloderinae, but present and often distinct in theMeloidoderinae genera Cryphodera and Meloidodera. The presence of male phasmids is considered as ancestral, and loss of phasmids as a derived character. [ABSTRACT FROM AUTHOR]

Three species of the family Tylenchidae, including one new and two known species, are described and illustrated. Atetylenchus minor n. sp. is characterised by its short body length of 633 (558-691) μm, MB = 45 (41-46), lateral field with four crenate incisures, stylet 12.0 (11.5-12.5) μm long, without distinct basal knobs but with swollen arms of the shaft at its base, V = 56.3 (53.7-59.3), absence of lateral vulval membranes, and conical tail 57 (51-62) μm long with a rounded tip. Morphological differences of the new species with four known species of the genus, namely A. abulbosus, A. graminus, A. amiri and A. metaporus, are discussed. Molecular phylogenetic studies of the new species using 1089 bp partial sequences of 18S rDNA revealed that the new species formed a clade with an unpublished species assigned to Psilenchus in Bayesian inference (BI) with low Bayesian posterior probability (BPP). This clade forms a sister clade to a major clade containing two species of Psilenchus and several belonolaim species and genera. The same result was achieved using maximum likelihood (ML) analysis. Morphological and molecular phylogenetic studies were also performed on two other species, Malenchus labiatus and Neothada cancellata, using 28S rDNA D2-D3 sequences. In the inferred Bayesian tree, M. labiatus formed a clade with other species of Malenchus with 28S information with maximal support (1.00 BPP), while N. cancellata formed a clade with Boleodorinae, again with maximal (1.00) BPP. [ABSTRACT FROM AUTHOR]

A new species of the genus Malenchus from the rainforest of Peru is described. Malenchus herrerai n. sp. was collected from an epiphytic moss associated with shade trees of coffee plantations (Coffea arabica) in the Chacra, Santa Fe, La Merced region, Peru. This new species is characterized by having a very well developed (robust and long) stylet. So far, it is the species with the largest stylet in the genus Malenchus. The robust stylet of M. herrerai n. sp. and its association with an epiphyte moss may indicate a host-parasite relationship between both organisms. In addition to the species description, morphological information of cuticular and sensory organs (amphids and pro-phasmids) is provided. These findings complement the existing scarce information on the morphology of the genus. [ABSTRACT FROM AUTHOR]

The stem and bulb nematodes of theDitylenchus dipsaci(Kühn) Filipjev species complex are obligate endoparasites of various agricultural plants, causing stunting and swelling and resulting in significant economic losses. Recently, a new closely relatedDitylenchusspecies,D. weischeriChizhov, Borisov and Subbotin, a parasite of the cosmopolitan herbaceous perennial weed,Cirsium arvense(L.) Scop., was described. Many countries impose quarantine restrictions for the presence ofD. dipsaciin imported plant and soil materials. In the current study, we developed PCR with species-specific primers for the rapid and reliable separation ofD. weischeriandD. dipsaciusing gel electrophoresis and melting curve analysis. Species-specific primer sets were designed based on the nucleotide sequence of the heat shock protein (hsp90) gene for both nematode species. The PCR protocol was verified using samples ofD. weischeri,D. dipsaciand the closely related species,D. gigas, which parasitizes broadbean (Vicia fabaL.). The species-specific primer sets were able to detectD. weischeriandD. dipsacifrom samples containing mixtures ofDitylenchusspecies. The PCR species-specific protocol should allow for more rapid identification ofDitylenchusspecies recovered from plant materials than previously possible. [ABSTRACT FROM AUTHOR]

Spermatogenesis in Ditylenchus arachis and D. dipsaci was studied using transmission electron microscopy. Spermatogenesis includes the formation of complexes of fibrous bodies (FB) and membranous organelles (MO) in the spermatocytes, which dissociate in separated MO and FB in the spermatids. Immature spermatozoa are unpolarised cells with separate FB and MO. Mature spermatozoa are arranged in chains. Ditylenchus dipsaci is unique in having MO that have already fused with the outer membrane in immature spermatozoa and have mature spermatozoa in the male testis, proving that not only insemination plays a role in spermiogenesis. Contrary to what has been described before, spermatogenesis in Ditylenchus, and other early diverging Tylenchomorpha, follow the typical 'rhabditid' pattern, while the absence of MO within Tylenchomorpha appears to be an apomorphic trait for the molecular defined clade of tylenchids that exclusively parasitise higher plants. This confirms the value of traits related to spermatogenesis in nematode phylogeny. [ABSTRACT FROM AUTHOR]