Pin nematodes (Paratylenchus spp.) are polyphagous parasitic species with a wide host range and geographical distribution; their diversity is unknown in the potato growing region of Alberta, Canada. The present study aims to provide morphological and molecular characterization of three pin nematode species, namely P. neoprojectus, P. tateae, and a new species, Paratylenchus enigmaticus sp. nov. All of them were recovered from the potato growing region of southern Alberta. The nematodes were isolated using the sieving and flotation-centrifugation method, and their morphology was assessed by light microscopy. Molecular characterization was performed using partial 18S, D2–D3 expansion domains of the 28S and ITS ribosomal genes. This study is the first report of molecular characterization of P. tateae and P. neoprojectus, being new records from southern Alberta, and two Spanish populations of P. tateae comprising the first report of this species in Europe. The phylogenetic analysis of the 18S, D2–D3 expansion domains of the 28S and ITS ribosomal DNA regions underscores the importance of using molecular data for accurate species identification and clarifies the status of P. nanus type B and P. sheri. Moreover, our findings will be useful to determine the impact of pin nematodes on potato production in future field research.

Understanding the existing nematode biodiversity is of significant concern because nematodes may divert nutrients from plants and use them for their own development and reproduction. The presence and diagnostics of Filenchus species occurring in southern Alberta have not been addressed in previous studies. Herein, we provide a comprehensive characterization of adult females of four known Filenchus species (F. cylindricus, F. hazenensis, F. sheri, and F. thornei) recovered from cultivated fields in southern Alberta. Three of the species are new records in Canada, while one is a native species that was previously described from the Canadian high arctic area. These organisms are mild parasitic species; we describe them here to enhance the visibility of soil nematodes and facilitate accurate species identification. The diagnostic resolution within Filenchus is low, because many species are described without adequate consideration of intra-specific variation. The species descriptions and molecular data obtained during the present study will reduce the confusion in examining the existing lineages among Filenchus species and will aid in improving phylogenetic resolution. Our results suggest that the known diversity of Canadian nemato-fauna has increased. However, more research is needed to further identify other genera and species of phytoparasitic nematodes that may occur in grasses, weeds, and wild plants present in cultivated areas. Moreover, the molecular characterization of these species from Canada, in comparison to a reference dataset (NCBI) of Tylenchidae nematodes, provides insight into the biogeography of nematodes.

The presence of plant-parasitic nematodes (PPNs) in cultivated areas is a limiting factor in achieving marketable crop yield. To control and alleviate the effects of these nematodes and determine appropriate management strategies, species-level identification is crucial. Therefore, we conducted a nematode diversity survey, which resulted in the detection of four Ditylenchus species in cultivated areas of southern Alberta, Canada. The recovered species had six lines in the lateral field, delicate stylets (>10 µm long), distinct postvulval uterine sacs, and pointed to rounded tail tips. The morphological and molecular characterization of these nematodes revealed their identity as D. anchilisposomus, D. clarus, D. tenuidens and D. valveus, all of which are members of the D. triformis group. All of the identified species were found to be new records in Canada except for D. valveus. Accurate Ditylenchus species identification is crucial because false-positive identification can result in the implementation of quarantine measures over the detected area. Our current study not only documented the presence of Ditylenchus species from southern Alberta, but also described their morpho-molecular characteristics and subsequent phylogenetic relationships with related species. The results of our study will aid in the decision on whether these species should become a part of nematode management programs since nontarget species can become pests due to changes in cropping patterns or climate.

Bursaphelenchus parapinasteriis redescribed morphologically and with new molecular characterisation. It was isolated from a deadPinus thunbergiion Changgang Mountain, Zhoushan Islands, Zhejiang Province, China. Detailed morphology of the spicule, female gonad, hemizonid position, arrangement of male caudal papillae, and female tail terminus shape are documented. The ITS-RFLP patterns and the ITS1/2, partial 28S D2-D3 and partial 18S gene sequences were characterised. The phylogenetic analyses revealed thatB. parapinasteribelongs to thehofmanni-groupsensuBraasch and is close toB. anamurius,B. hofmanni,B. mazandaranense,B. paracorneolus,B. pinasteriandB. ulmophilus. A diagnostic key to species of thehofmanni-group is presented.

The present study provides the morphological and molecular characterization of Boleodorus thylactus and B. volutus populations, recovered from agricultural fields of southern Alberta. Despite a significant abundance of this group of nematodes, none of the Boleodorus species were previously reported in Canada. Therefore, representative adult specimens of each population were photographed and examined morphometrically. Phylogenetic trees were reconstructed using partial D2–D3 expansion segments of the 28S and 18S rDNA sequences to understand the relationships of Boleodorus species with Tylenchidae-related genera. Boleodorus species are relevant to soil ecological studies and therefore we summarized the important morphological and morphometric characters in tabular form for easy and efficient species identification. Moreover, we discuss the associated hosts and the distribution of all described Boleodorus species. This study will serve as a guide and basic framework for species diagnostics in the genus Boleodorus and will aid in filling the gaps in our knowledge of the species present in our cultivated lands.

Summary: The present study describes a new Ditylenchus species, isolated from the bulbs of the Persian buttercup (Ranunculus asiaticus L.) imported from Israel at the Ningbo plant quarantine lab, Ningbo, P.R. China. Ditylenchus israelensis n. sp. is an amphimictic species; females have six incisures in the lateral field, a long and slim body, a delicate, short stylet (7-8 μm) with small and rounded knobs, excretory pore in the anterior region of the basal pharyngeal bulb, posteriorly located vulva (V = 78.6-83.1), a short PUS (15.0-24.0 μm), and a long conical tail with a pointed terminus. Males are similar to females in general morphology and have 14.0-18.0 μm long spicules. The new species was also characterised molecularly using 18S, ITS and D2-D3 expansion segments of 28S rDNA genes. Our phylogenetic analyses showed its independent position among available Ditylenchus species and a close phylogenetic affinity with D. valveus. Several Ditylenchus species are regulated pests; their detection in a given sample can implement quarantine measures. However, to our knowledge D. israelensis n. sp. did not cause any damage to the R. asiaticus bulbs. In addition, future studies regarding fecundity and host association may shed some light on the pathogenic potential of D. israelensis n. sp.