rss_2.0Journal of Nematology FeedSciendo RSS Feed for Journal of Nematology of Nematology Feed to Anatomy<abstract> <title style='display:none'>Abstract</title> <p><italic>Strongyloides stercoralis</italic>, commonly known as the human threadworm, is a skin-penetrating gastrointestinal parasitic nematode that infects hundreds of millions of people worldwide. Like other <italic>Strongyloides</italic> species, <italic>S. stercoralis</italic> is capable of cycling through a single free-living generation. Although <italic>S. stercoralis</italic> and the free-living nematode <italic>Caenorhabditis elegans</italic> are evolutionarily distant, the free-living adults of <italic>S. stercoralis</italic> are similar enough in size and morphology to <italic>C. elegans</italic> adults that techniques for generating transgenics and knockouts in <italic>C. elegans</italic> have been successfully adapted for use in <italic>S. stercoralis</italic>. High-quality genomic and transcriptomic data are also available for <italic>S. stercoralis</italic>. Thus, one can use a burgeoning array of functional genomic tools in <italic>S. stercoralis</italic> to probe questions about parasitic nematode development, physiology, and behavior. Knowledge gained from <italic>S. stercoralis</italic> will inform studies of other parasitic nematodes such as hookworms that are not yet amenable to genetic manipulation. This review describes the basic anatomy of <italic>S. stercoralis</italic>.</p> </abstract>ARTICLEtrue Report of Mermithidae (Enoplea: Mermithida) Parasitizing Adult Stable Flies in Japan<abstract> <title style='display:none'>Abstract</title> <p>Mermithidae is a family of nematodes that parasitize a wide range of invertebrates worldwide. Herein, we report nematodes that were unexpectedly found in three of 486 adult stable flies (<italic>Stomoxys calcitrans</italic>) captured from three farms (F1, F2, and F3) in different regions of Gifu Prefecture, Japan. We aimed to characterize these nematodes both at the morphological and molecular level. Morphological studies revealed that the nematodes were juveniles of Mermithidae. Phylogenetic analysis based on 18S and 28S rDNA indicated that the mermithids from farms F1 and F2 could be categorized into the same cluster as <italic>Ovomermis sinensis</italic> and <italic>Hexamermis</italic> sp., whereas the mermithid from farm F3 clustered with <italic>Amphimermis</italic> sp. Additionally, these mermithids could be categorized within the same clusters as related mermithids detected in Japan that parasitize various arthropod orders. Our findings suggest that these stable flies may have been parasitized by mermithids already present in the region and that genetically distinct species of mermithids occur across Japan. To the best of our knowledge, this is the first report of mermithids parasitizing adult stable flies in Japan.</p> </abstract>ARTICLEtrue the use of metabarcoding to reveal eukaryotic associations with mononchids nematodes<abstract> <title style='display:none'>Abstract</title> <p>Nematodes play a vital ecological role in soil and marine ecosystems, but there is limited information about their dietary diversity and feeding habits. Due to methodological challenges, the available information is based on inference rather than confirmed observations. The lack of correct dietary requirements also hampers rearing experiments. To achieve insight into the prey of mononchid nematodes, this study employed high-throughput Illumina paired-end sequencing using universal eukaryotic species 18S primers on 10 pooled mononchid nematode species, namely <italic>Mylonchulus brachyuris, M. brevicaudatus, Mylonchulus</italic> sp., <italic>Clarkus parvus, Prionchulus</italic> sp. <italic>M. hawaiiensis, M. sigmaturellus, M. vulvapapillatus, Anatonchus</italic> sp. and <italic>Miconchus</italic> sp. The results indicate that mononchids are associated with a remarkable diversity of eukaryotes, including fungi, algae, and protists. While the metabarcoding approach, first introduced here for mononchids, proved to be a simple and rapid method, it has several limitations and crucial methodological challenges that should be addressed in future studies. Ultimately, such methods should be able to evaluate the dietary complexity of nematodes and provide a valuable avenue for unraveling the dietary requirements of previously unculturable nematodes. This can contribute to the methodology of understanding their feeding habits and contributions to ecosystem dynamics.</p> </abstract>ARTICLEtrue Nematodes Associated with Grasses Grown for Seed in the Willamette Valley of Oregon<abstract> <title style='display:none'>Abstract</title> <p>Plant-parasitic nematodes (PPN) are an understudied pathogen group in the Oregon cool-season grass seed cropping system. In this survey, the PPN associated with annual ryegrass, bentgrass, fine fescue, orchardgrass, perennial ryegrass, and tall fescue were determined. Thirty-seven fields were sampled in the 2022 or 2023 growing season by collecting 10 soil cores in each of six 100-m transects for nematode extraction and visual identification. PerMANOVA testing indicated significant differences in PPN community composition across grass host and sampling time. <italic>Pratylenchus</italic> and <italic>Meloidogyne</italic> were the most commonly encountered nematodes, with maximum population densities of 1,984 and 2,496 nematodes/100 g soil, respectively. Sequencing of the COX1 gene region indicated the presence of <italic>P. crenatus, P. fallax, P. neglectus, P. penetrans</italic>, and <italic>P. thornei</italic>, with some of these species being detected for the first time on these grass hosts. The only <italic>Meloidogyne</italic> sp. found in these grasses was <italic>M. nassi</italic>, based upon sequencing of the ITS gene region. This first-of-its-kind survey indicates the need for further assessment of the impact of these PPNs on yield and stand longevity in cool-season grass seed fields in Oregon.</p> </abstract>ARTICLEtrue Efficacy of Entomopathogenic Nematodes Plus an Adjuvant against and in Aboveground Applications<abstract> <title style='display:none'>Abstract</title> <p>In the southern United States, corn earworm, <italic>Helicoverpa zea</italic> (Boddie), and soybean looper, <italic>Chrysodeixis includens</italic> (Walker) are economically important crop pests. Although Bt crops initially provided effective control of target pests such as <italic>H. zea</italic>, many insect pests have developed resistance to these Bt crops. Alternative approaches are needed, including biological control agents such as entomopathogenic nematodes (EPNs). However, the effectiveness of EPNs for aboveground applications can be limited due to issues such as desiccation and ultraviolet radiation. Effective adjuvants are needed to overcome these problems. Ten strains of EPNs were tested for virulence against eggs, first to fourth instars, fifth instars, and pupae of <italic>H. zea</italic> and <italic>C. includens</italic> in the laboratory. These 10 EPN strains were <italic>Heterorhabditis bacteriophora</italic> (HP88 and VS strains), <italic>H. floridensis</italic> (K22 strain), Hgkesha (Kesha strain), <italic>Steinernema carpocapsae</italic> (All and Cxrd strains), <italic>S. feltiae</italic> (SN strain), <italic>S. rarum</italic> (17c+e strain), and <italic>S. riobrave</italic> (355 and 7–12 strains). EPNs could infect eggs of <italic>H. zea</italic> or <italic>C. includens</italic> in the laboratory, but the infection was low. The mortality caused by 10 EPN strains in seven days was significantly higher for the first to fourth instars of <italic>H. zea</italic> compared to the control, as was the fifth instars of <italic>H. zea</italic>. Similarly, for the first to fourth and fifth instars of <italic>C. includens</italic>, the mortality was significantly higher compared to the controls, respectively. However, only <italic>S. riobrave</italic> (355) had significantly higher mortality than the control for the pupae of <italic>H. zea</italic>. For the pupae of <italic>C. includens</italic>, except for <italic>H. bacteriophora (HP88)</italic>, <italic>S. rarum (17c+e)</italic>, and <italic>H. floridensis</italic> (K22), the mortality of the other seven strains was significantly higher than the control. Subsequently, <italic>S. carpocapsae</italic> (All) and <italic>S. riobrave</italic> (7–12) were chosen for efficacy testing in the field with an adjuvant 0.066% Southern Ag Surfactant (SAg Surfactant).</p> <p>In field experiments, the SAg Surfactant treatment significantly increased the mortality and EPN infection for <italic>S. carpocapsae</italic> (All) on first instars of <italic>H. zea</italic> in corn plant whorls. On soybean plants, with the SAg Surfactant, <italic>S. carpocapsae</italic> (All) was more effective than <italic>S. riobrave</italic> (7–12) on fifth instars of <italic>C. includens</italic>. This study indicates that EPNs can control <italic>H. zea</italic> and <italic>C. includens</italic>, and SAg Surfactant can enhance EPN efficacy.</p> </abstract>ARTICLEtrue distribution and phoretic associations of the viviparous nematode with dung beetles in Japan<abstract> <title style='display:none'>Abstract</title> <p>Viviparity is generally considered to be rare in animals. In nematodes, only six species of Rhabditida are viviparous. Five of these species have been identified in association with <italic>Onthophagus</italic> dung beetles, with <italic>Tokorhabditis atripennis</italic> being repeatedly isolated from the dung beetle <italic>Onthophagus atripennis</italic> in Japan. <italic>T. atripennis</italic> is easy to culture in a laboratory setting, and its host, <italic>O. atripennis</italic>, is distributed all over Japan. Therefore, <italic>T. atripennis</italic> is an ideal candidate for ecological and evolutionary studies on viviparity. However, the extent of their distribution and relationship with dung beetles, as well as habitats, remain unclear. In the present study, we conducted field surveys and successfully isolated 27 strains of viviparous nematodes associated with tunneler dung beetles from various regions of Japan, all of which were identified as <italic>T. atripennis</italic>. <italic>T. atripennis</italic> exhibited a strong association with <italic>Onthophagus</italic> dung beetles, especially <italic>O. apicetinctus</italic> and <italic>O. atripennis</italic>. And it was predominantly found in specific anatomical locations on the beetle bodies, such as the ‘groove between pronotum and elytron’ and the ‘back of the wings’. Our findings suggest that <italic>Onthophagus</italic> species are the primary hosts for <italic>T. atripennis</italic>, and <italic>T. atripennis</italic> exhibits a close relationship with the living environments of tunneler beetles. This association may play a significant role in the evolution of viviparity in nematodes.</p> </abstract>ARTICLEtrue of Weed Species for Host Status to the Root-Knot Nematodes and Race 4<abstract> <title style='display:none'>Abstract</title> <p>Weeds that compete with valuable crops can also host plant-parasitic nematodes, acting as a source of nematode inoculum in a field and further damaging crops. The host status of 10 weed species commonly found in North Carolina, USA, was determined for the root-knot nematodes <italic>Meloidogyne enterolobii</italic> and <italic>M. incognita</italic> race 4 in the greenhouse. Each weed species was challenged with 5,000 eggs/plant of either <italic>M. enterolobii</italic> or <italic>M. incognita</italic> race 4, with five replicate plants per treatment in two separate greenhouse trials. Root galling severity and total number of nematode eggs per root system were recorded 60 days after inoculation. Reproduction factor (Rf = final nematode population/initial nematode population) was calculated to determine the host status of each weed species to <italic>M. enterolobii</italic> and <italic>M. incognita</italic> race 4. Four weed species (<italic>Datura stramonium, Digitaria sanguinalis, Senna obtusifolia,</italic> and <italic>Cyperus esculentus</italic>) were poor hosts (Rf &lt; 1) to both nematode species, and roots of these weed plants did not display galling. Four weed species (<italic>Ipomoea hederacea, Amaranthus palmeri, Portulaca pilosa,</italic> and <italic>Ipomoea lacunosa</italic>) were hosts (Rf &gt; 1) to both nematode species, and all had observable root gall formation. <italic>Sida rhombifolia</italic> and <italic>Cyperus rotundus</italic> were poor hosts to <italic>M. enterolobii</italic> but susceptible hosts to <italic>M. incognita</italic>. This study documents a differential host status of some common weeds to <italic>M. enterolobii</italic> and <italic>M. incognita</italic> race 4, and these results highlight the necessity of managing root-knot nematodes through controlling weeds in order to protect valuable crops.</p> </abstract>ARTICLEtrue Migration of Second-stage Juveniles of as Influenced by Temperature and Host<abstract> <title style='display:none'>Abstract</title> <p>Infective second-stage juveniles (J2) of <italic>Meloidogyne</italic> spp. migrate towards host roots, which depends on several factors, including root exudates and soil temperature. Although <italic>Meloidogyne enterolobii</italic> is a highly virulent nematode that affects major agricultural crops worldwide, there is limited ecological data about it. The objective of this study was to determine the J2 migration pattern vertically in 14-cm long segmented soil columns towards tomato (<italic>Solanum lycopersicum</italic>) and marigold (<italic>Tagetes patula</italic>) roots, each grown at two soil temperatures (20 or 26ºC). Bottomless cups with tomatoes or marigolds were attached to the top of each column; cups with no plants were used as untreated controls. Juveniles (1,000/column) were injected into a hole located 1 cm from the bottom of each column. The apparatuses were placed in growth chambers at 20 or 26ºC, and J2 were allowed to migrate for 3, 6, 9, or 12 days after injection (DAI). At each harvest, J2 were extracted from each ring of the columns and counted to compare their distribution, and root systems were stained to observe root penetration. <italic>M. enterolobii</italic> migrated over 13 cm vertically 3 DAI regardless of temperature, even without plant stimuli. The vertical migration was greater at 26ºC, where 60% of active J2 were found at distances &gt;13 cm at 12 DAI. Temperature did not affect root penetration. Overall, a greater number of J2 was observed in tomato roots, and root penetration increased over time.</p> </abstract>ARTICLEtrue of n. sp. (Rhabditida, Anguinidae) from Iran based on morphological and molecular data<abstract> <title style='display:none'>Abstract</title> <p><italic>Nothotylenchus savadkoohensis</italic> n. sp. was recovered from rotten wood samples of an unidentified forest tree in the Mazandaran province and described herein. It is mainly characterized by an elongated conoid tail ending in a sharply pointed tip and four lines in the lateral field. Females of the new species have 379–662 μm long bodies with 5.8–6.9 μm long stylets ending in fine posteriorly sloping knobs, the metacorpus not valvate, the pharyngeal bulb slightly overlapping the intestine, and the vulva at 76.5–84.0% of body length. Males are also common and have 13.0–14.5 μm long spicules and bursa cloacal. By having an elongated conoid tail and four lines in the lateral field, the new species comes close to four known species, namely <italic>N. acris, N. acutus, N. antricolus</italic>, and <italic>N. truncatus</italic>. The morphological differences between the new species and the abovementioned species are discussed. The new species was sequenced for its D2–D3 segment of LSU and ITS rDNA regions. In the LSU phylogenetic tree, the currently available LSU sequences of the genus <italic>Nothotylenchus</italic> occupied distant placements from each other and the LSU sequence of the new species formed clade with a sequence assigned to <italic>Neotylenchus</italic> sp. In ITS phylogeny, the newly generated sequence of the new species formed a clade with a clade that includes sequences of <italic>Ditylenchus</italic> sp. and <italic>Neomisticius platypi</italic> and <italic>N. variabilis</italic>.</p> </abstract>ARTICLEtrue host resistance as a tool for managing in Louisiana<abstract> <title style='display:none'>Abstract</title> <p>The reniform nematode, <italic>Rotylenchulus reniformis</italic>, is a major yield-limiting pest of upland cotton (<italic>Gossypium hirsutum</italic>) in the United States that has been steadily increasing in incidence in many states. Reniform nematode-resistant cotton cultivars have recently become commercially available for cotton producers; however, few field trials have evaluated their efficacy as a nematode management tool. The aim of this study was to evaluate reniform nematode population development, plant growth, and seed cotton yield of reniform nematode-resistant cotton cultivars in two nematode-infested fields in Louisiana. Replicated small-plot field trials were conducted in St. Joseph, LA (NERS field) and Winnsboro, LA (MRRS field) during the 2022 and 2023 growing seasons. In 2022, cultivars evaluated included: (1) DP 1646 B2XF (susceptible/tolerant), (2) DP 2141NR B3XF (resistant), (3) PHY 332 W3FE (resistant), (4) PHY 411 W3FE (resistant), and (5) PHY 443 W3FE (resistant). In 2023, an additional susceptible cotton cultivar, PHY 340 W3FE, was also included. All nematode-resistant cotton cultivars evaluated provided suppression of reniform nematode population development relative to that of the susceptible cotton cultivars, with suppression of nematode soil population densities at harvest ranging from 49 – 81% relative to DP 1646 B2XF. The resistant cultivar PHY 411 W3FE provided the most consistent suppression of reniform nematode population development, reducing reniform nematode soil population densities at harvest in both field locations and both trial years. In contrast, DP 2141NR B3XF only reduced soil population densities at harvest in the NERS field in 2023. Despite relatively consistent nematode suppression and improvements in plant vigor ratings and canopy coverage associated with the resistant cotton cultivars, a yield increase was only observed with PHY 332 W3FE and PHY 411 W3FE planted at the NERS field in 2023. Despite strong resistance to reniform nematode in the evaluated cotton cultivars, nematode soil population densities still increased during the growing season in plots planted with resistant cotton cultivars, emphasizing the need for additional management tactics to use alongside host resistance. This study indicates that new reniform nematode-resistant cotton cultivars show promising potential to reduce nematode population development during the growing season in Louisiana.</p> </abstract>ARTICLEtrue of Ferrari (Coleoptera: Curculionidae: Scolytinae) parasitized by the nematode Poinar (Tylenchida: Allantonematidae) to different colors of light<abstract> <title style='display:none'>Abstract</title> <p><italic>Metaparasitylenchus hypothenemi</italic> is a nematode that naturally parasitizes <italic>Hypothenemus hampei</italic> in a coffee-producing region in Chiapas, Mexico. This study investigated changes in the attraction of parasitized borers to light. We compared the attraction of adult <italic>H. hampei</italic> females (parasitized and uninfected) to 14 different light wavelengths (350–670 nm) with a control (570 nm, yellow) under laboratory conditions. The response ranges of non-parasitized and parasitized borers were 370–650 nm and 340–650 nm, respectively. The attraction curve showed a similar shape in both borer groups (parasitized and non-parasitized), but a wide wavelength range (380–590 nm) attracted more parasitized than non-parasitized borers. The maximum response of the uninfected borers occurred at 520 nm (green), while parasitized borers exhibited three response peaks (380 nm, violet; 460 nm, blue; 520 nm, green). Parasitized borers were significantly more attracted to green light (520 nm) than to the control. The altered attraction to light in borers parasitized by <italic>M. hypothenemi</italic> is discussed from the perspective of possible host manipulation and the natural prevalence of this parasite.</p> </abstract>ARTICLEtrue of pest nematodes associated with soybean () in Wisconsin from 1998 to 2021<abstract> <title style='display:none'>Abstract</title> <p>The prevalence of <italic>Heterodera glycines</italic> and other cyst and vermiform genera was determined from 8,009 soil samples over two decades. Prevalence of cyst nematodes for farms increased from 16% in 1998 to 1999, reaching a peak of 40%, with marked differences among Wisconsin’s nine agricultural districts in how much the odds of a positive test increased. Estimates at the sample scale also increased over time but peaked at 29%. Assay of all nematodes beginning in 2012 showed <italic>Pratylenchus</italic>, <italic>Helicotylenchus</italic>, and <italic>Xiphinema</italic> to be more prevalent in Wisconsin soybean fields than cyst nematodes. Prevalence estimates for <italic>Pratylenchus</italic> and <italic>Helicotylenchus</italic> for soybean and rotation crops ranged from 76 to 89% and 58 to 83%, respectively. Species identification of <italic>Pratylenchus</italic> from a subset of the samples revealed six species. The majority of cyst-positive samples were infested with <italic>Pratylenchus</italic>, and count data showed that the number of cyst eggs and juveniles per 100 cm<sup>3</sup> soil was 60% lower in samples positive for <italic>Pratylenchus</italic>. The influence was reciprocal, as <italic>Pratylenchus</italic> population densities were 41% lower in samples positive for cyst nematodes, suggesting a competitive interaction. The Wisconsin soybean nematode testing program provides a useful model for estimating nematode prevalence using citizen-based surveys.</p> </abstract>ARTICLEtrue and description of the European dagger nematode on peach ( L.) in Canada<abstract> <title style='display:none'>Abstract</title> <p>The study reports the detection of <italic>Xiphinema diversicaudatum</italic> in a peach field in Ontario, Canada. Comprehensive population characterization involved morphological and molecular analyses using 18S and 28S rDNA sequences. Morphological and molecular analysis demonstrated a close relationship between the Ontario population and those from Central Europe. This is the first report of <italic>X. diversicaudatum</italic> from peaches (<italic>Prunus persica</italic>) in Canada and in North America.</p> </abstract>ARTICLEtrue Draft Transcriptome Announcement of<abstract> <title style='display:none'>Abstract</title> <p><italic>Anguina tritici</italic>, the wheat seed gall nematode, causes the ‘ear-cockle’ or seed gall disease of wheat (<italic>Triticum sp.</italic>), leading to an extensive decline of yield (30–70%) in underdeveloped wheat cultivating countries of the world. The nematode is known to survive in anhydrobiotic conditions for up to 32 years. Here, we present the first transcriptome assembly of <italic>A. tritici</italic>, which will be a valuable resource for understanding the genes responsible for nematode survival and above-ground plant parasitism. The final 133.2 Mb assembly consists of 105606 open reading frames (including isoforms) with the following BUSCO scores against Nematoda database: 80.3% complete (16.4% single copy and 63.9% duplicated), 2.1% fragmented, and 17.6% missing.</p> </abstract>ARTICLEtrue distribution of plant-parasitic nematodes on bentgrass golf greens in Missouri and Indiana<abstract> <title style='display:none'>Abstract</title> <p>Control of plant-parasitic nematodes (PPNs) on golf putting greens with nematicides is dependent on the seasonal occurrence and depth distribution of target PPN populations. This study aimed to determine if plant-parasitic nematode populations on golf course putting greens in Missouri and Indiana peaked at a targetable depth at a specific time in the year, focusing primarily on lance (<italic>Hoplolaimus</italic> spp.) and root-knot (<italic>Meloidogyne</italic> spp.) nematodes. To elucidate species diversity in the region, rDNA from a subset of lance and root-knot nematodes was sequenced and analyzed, with additional micromorphology of a lance nematode assessed in scanning electron micrographs (SEM). Soil samples were taken to a depth of 25 cm and stratified into 5 cm increments during April, June, August and October at seven sites across Missouri, three in the Kansas City metro of Kansas in 2021 and in ten sites across Indiana in 2022. Samples were stratified in five-centimeter increments and aggregated for a total of 100 cm<sup>3</sup> of soil at each depth for each sampling. Samples were processed using a semi-automatic elutriator followed by the sucrose-flotation method, and populations were counted using a hemocytometer and recorded. For molecular characterization, rDNA was extracted and analyzed from 31 individual lance nematodes from one site in Missouri and eight sites in Indiana, and 13 root-knot nematodes from nine sites across Indiana. A significant interaction occurred between sampling month and depth for lance and ring nematodes Missouri/KS, with both PPN populations peaking at the 0–5 cm depth during October, which is well after most targeted nematicide applications are applied. Ring nematodes in Indiana did not follow this trend and were most abundant in August at a depth of 0–5 cm. No significant interaction between depth and month occurred for lance or root-knot nematodes in Indiana, or root-knot nematodes in Missouri/KS. <italic>Hoplolaimus stephanus</italic> and <italic>H. magnistylus</italic> were the lance species identified on golf greens, and <italic>Meloidogyne naasi</italic>, <italic>M. graminicola</italic> and <italic>M. marylandi</italic> were the root-knot species identified. Scanning-electron micrographs confirmed morphological characteristics unique to <italic>H. stephanus</italic>.</p> </abstract>ARTICLEtrue status of melon, carrot, and -susceptible and -resistant cotton, cowpea, pepper, and tomato for from California<abstract> <title style='display:none'>Abstract</title> <p>The host status of carrot, melon, and susceptible and resistant cultivars of tomato, cotton, cowpea, and pepper for a California isolate of the peach root-knot nematode <italic>Meloidogyne floridensis</italic> was determined in greenhouse pot experiments. It was compared to a race 3 isolate of <italic>M. incognita</italic>. Melon was an excellent host for both isolates and roots were heavily galled after the 8-week trial. Carrot was a host for <italic>M. incognita</italic>, but a poor host for <italic>M. floridensis</italic>, although both isolates caused similar levels of galling. Susceptible cotton was a good host for <italic>M. incognita</italic> race 3, but a poor host for <italic>M. floridensis</italic>. Susceptible tomato, cowpea, and pepper were good hosts for both isolates. The <italic>M. incognita</italic> resistance in tomato and pepper was broken by <italic>M. floridensis</italic>. Resistant cowpea was a maintenance host as population levels of <italic>M. floridensis</italic> remained virtually unchanged over the trial period. We conclude that <italic>M. floridensis</italic> poses a risk to some important vegetable crops in California, as it reproduces on most vegetable crops, including some cultivars that are resistant to <italic>M. incognita</italic>. On susceptible crops, the reproduction of <italic>M. floridensis</italic> was always significantly less than that of <italic>M. incognita</italic>, and we hypothesize that in mixed species field populations, <italic>M. incognita</italic> will outcompete <italic>M. floridensis</italic>. This study demonstrates that efforts to limit the spread and prevent further introductions of <italic>M. floridensis</italic> in California are important to maintain the effectiveness of plant resistance as a nematode management strategy in vegetable crops.</p> </abstract>ARTICLEtrue Whole Genome Assembly and Annotation of<abstract> <title style='display:none'>Abstract</title> <p><italic>Parelaphostrongylus tenuis</italic> causes ungulate morbidity and mortality in eastern and central North America, but no reference genome sequence exists to facilitate research. Here, we present a <italic>P. tenuis</italic> genome assembly and annotation, generated with PacBio and Illumina technologies. The assembly is 491 Mbp, with 7285 scaffolds and 185 kb N50.</p> </abstract>ARTICLEtrue Movement in Entomopathogenic Nematodes: Aggregation Levels Vary Based on Context<abstract> <title style='display:none'>Abstract</title> <p>Maintenance of an aggregated population structure implies within-species communication. In mixed-species environments, species-specific aggregations may reduce interspecific competition and promote coexistence. We studied whether movement and aggregation behavior of three entomopathogenic nematode species changed when isolated, as compared to mixed-species arenas. Movement and aggregation of <italic>Steinernema carpocapsae</italic>, <italic>S. feltiae</italic> and <italic>S. glaseri</italic> were assessed in sand. Each species demonstrated significant aggregation when alone. Mixed-species trials involved adding two species of nematodes, either combined in the center of the arena or at separate corners. While individual species became less aggregated than in single-species conditions when co-applied in the same location, they became more aggregated when applied in separate corners. This increased aggregation in separate-corner trials occurred even though the nematodes moved just as far when mixed together as they did when alone. These findings suggest that maintenance of multiple species within the same habitat is driven, at least in part, by species-specific signals that promote conspecific aggregation, and when the species are mixed (as occurs in some commercial formulations involving multiple EPN species), these signaling mechanisms are muddled.</p> </abstract>ARTICLEtrue analysis of soil nematode biodiversity from five different fruit orchards in Osmaneli district, Bilecik, Türkiye<abstract> <title style='display:none'>Abstract</title> <p>Nematode population densities were determined in 60 soil and root samples collected from 6 fruit orchards in the Bilecik province (western Turkey), between April 2022 and June 2022. The total number of identified nematodes have reached up to 2418 individuals (number of female: 1036; male: 154; and juvenile: 1228). They belong to 54 species, 54 genera, 33 families and 11 orders. Plant parasitic nematodes that were detected mostly are listed as follows: <italic>Helicotylenchus</italic> (6,12 %), <italic>Pratylenchus</italic> (5,74 %), <italic>Paratylenchus</italic> (4.83 %), <italic>Xiphinema</italic> (3,06 %), <italic>Tylenchorhynchus</italic> (2,19 %), <italic>Malenchus</italic> (1.94 %) and <italic>Tylenchus</italic> (1.19 %). According to the maturity index analysis, mean values showed the highest maturity level at peach trees (MI value: 3,52), followed by; walnut trees (MI value: 2.49), cherry trees (MI value: 2.15), nectarine trees (MI value: 1.86), plum trees (MI value: 1.57), and olive trees (MI value: 1.42). Mostly the diverse group in terms of species richness was within the order Dorylaimida. The nematodes associated with peach and walnut trees here showed the most stable environments in terms of soil nematode community structure.</p> </abstract>ARTICLEtrue report of on hemp () in Oregon<abstract> <title style='display:none'>Abstract</title> <p>Hemp is a crop that has gained interest in Washington and Oregon. As with other crops, hemp production faces challenges due to biotic factors, including plant-parasitic nematodes. During a survey for plant-parasitic nematodes associated with hemp, <italic>Meloidogyne</italic> sp. was found in a composite root sample collected in Oregon. Morphological characterization of second-stage juveniles identified the nematode as <italic>Meloidogyne hapla</italic>. Molecular identification confirmed the population as <italic>M. hapla</italic>. To our knowledge, this is the first report of <italic>M. hapla</italic> on hemp in the Pacific Northwest of the United States.</p> </abstract>ARTICLEtrue