rss_2.0Sciendo RSS Feed for Journal of Nematologyhttps://sciendo.com/journal/JOFNEMhttps://www.sciendo.comhttps://sciendo-parsed.s3.eu-central-1.amazonaws.com/65f35797812d8816c96ad496/cover-image.jpghttps://sciendo.com/journal/JOFNEM140216https://sciendo.com/article/10.2478/jofnem-2024-0038<abstract> <title style='display:none'>Abstract</title> <p>Pinewood nematodes threaten forest health and continue to interfere with international trade because they can be spread around the globe via nematode-infested wood. International Standards for Phytosanitary Measure (ISPM-15) requires that all pine wood be treated at 56°C for 30 min to ensure that all pests and pathogens are killed within sawn wood, whereas fumigation with methyl bromide is the currently approved practice and widely used in treating whole logs. A method of treatment that uses less energy and time or does not rely on environmentally damaging gases is urgently needed. Because vacuum with steam has shown promise in treating several different commodities, the purpose of this study was to use it to eradicate pinewood nematodes in whole logs. Three protocols were applied: 1) 48°C for 15 min., 2) 56°C for 30 min., and 3) 60°C for 60 min. The third protocol reduced the population to statistically zero; however, some samples contained at least 1 survivor. Unfortunately, these surviving nematodes increased in number one month after treatment, and one year later, they continued to reproduce in the wood. Therefore, this protocol needs to be further refined to remove pinewood nematodes completely. Explanation of the survival of individual nematodes within whole logs remains a matter for conjecture: 1) certain portions of the wood were somehow insulated from the heat and did not achieve the lethal temperature, and 2) survival stages may be able to survive temperatures that are deadly to the normal life stages.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00382024-10-05T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0032<abstract> <title style='display:none'>Abstract</title> <p>Based on molecular markers, mating experiments, morphological observations and ecological data, two <italic>Pristionchus</italic> species (Nematoda: Diplogastridae) new to science are described. Both were collected from different Scarabaeoid beetles in South Korea, have a gonochoristic mode of reproduction and fall into a sub-clade of the <italic>pacificus</italic> clade. <italic>Pristionchus coreanus</italic> n. sp. does not show a eurystomatous morph under laboratory conditions and might therefore be suitable for the study of gain and loss of polymorphism. <italic>Pristionchus hangukensis</italic> n. sp. is phylogenetically close to Chinese and Japanese species and helps to separate an Asian clade from an American clade.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00322024-10-04T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0028<abstract> <title style='display:none'>Abstract</title> <p><italic>Mesodorylaimus pini</italic> n. sp., a new species isolated from the bark and cambium layer of a dead black pine tree is characterized herein using integrative taxonomy, considering both morphological and molecular phylogenetic analyses of the 18S- and 28S-rRNA genes. <italic>Mesodorylaimus pini</italic> n. sp. is characterized by having a medium-sized body 1.50–1.89 mm long; lip region angular and offset by a depression; a relatively long odontostyle (17.0–19.0 μm); vulval opening a transverse slit, positioned slightly posteriorly; <italic>pars refringens vaginae</italic> with two elongated drop-shaped to spindle-shaped sclerotizations; an intestine-prerectum junction with a long anteriorly directed conical or tongue-like projection; a relatively long female tail (115–187 μm); spicules 48.0–57.0 μm long; and regularly spaced 7–8 ventromedian supplements. It is closest to <italic>M. subtilis</italic>, especially in having similar body length and number of ventromedian supplements but can be differentiated from <italic>M. subtilis</italic> by the longer odontostyle, tongue-like projection, and longer spicules. The phylogenies based on the 18S- and 28S-rRNA sequences showed a well-supported sister relation of <italic>M. pini</italic> n. sp. with <italic>M. subtilis, M. japonicus, M. bastiani, M. pseudobastiani, Calcaridorylaimus castaneae, C. heynsi</italic>, and other member species of the group.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00282024-09-30T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0036ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00362024-09-11T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0063<abstract> <title style='display:none'>Abstract</title> <p><italic>Pristionchus pacificus</italic> is a free-living nematode that shares many features with <italic>Caenorhabditis elegans</italic>, such as its short generation time and hermaphroditism, but also exhibits novel traits, i.e., a mouth-form dimorphism that enables predation. The availability of various genetic tools and genomic resources make it a powerful model organism for comparative studies. Here, we present an updated genome of the <italic>P. pacificus</italic> strain PS1843 (Washington) that is most widely used for genetic analysis. Assembly of PacBio reads together with reference-guided scaffolding resulted in a chromosome-scale genome spanning 171Mb for the PS1843 strain. Whole genome alignments between the <italic>P. pacificus</italic> PS1843 genome and the genome of the <italic>P. pacificus</italic> reference strain PS312 (California) revealed megabase-sized regions on chromosomes III, IV, and X that explain the majority of genome size difference between both strains. The improved PS1843 genome will be useful for future forward genetic studies and evolutionary genomic comparisons at the intra-species level.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00632024-09-11T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0029<abstract> <title style='display:none'>Abstract</title> <p>The hop cyst nematode, <italic>Heterodera humuli</italic>, is the most common plant-parasitic nematode associated with hop worldwide. This study reports the draft genome of <italic>H. humuli</italic> generated on the PacBio Sequel IIe System with the ultra-low DNA input HiFi sequencing method, and the corresponding genome annotation. This genome resource will help further studies on <italic>H. humuli</italic> and other cyst nematodes.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00292024-08-28T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0033<abstract> <title style='display:none'>Abstract</title> <p>Sweetpotato is an important crop whose roots are consumed by people worldwide. <italic>Meloidogyne enterolobii</italic> stands out as a highly deleterious variant among the species of root-knot nematode that causes significant damage in sweetpotato. In the present study, the activity of four nematicides against <italic>M. enterolobii</italic> was assessed both <italic>in vitro</italic> and in growth cabinet experiments. After 48 hours of exposure, fluopyram and cyclobutrifluram had a greater negative effect on the motility of <italic>M. enterolobii</italic> second-stage juveniles (J2s) compared to fluensulfone and hymexazol, with respective median effective concentration (EC₅₀) values of 0.204, 0.423, 22.335 and 216.622 mg L⁻¹. When <italic>M. enterolobii</italic> eggs were incubated for 72 hours at the highest concentration of each nematicides, the inhibitory hatching effect of cyclobutrifluram (2.5 mg L⁻¹), fluopyram (1.25 mg L⁻¹) and fluensulfone (80 mg L⁻¹) surpassed 85%, whereas hymexazol (640 mg L⁻¹) was only 67%. Similar results were observed in growth cabinet experiments as well. The disease index (DI) and gall index (GI) were significantly decreased by all four nematicides compared to the control. However, the application of hymexazol did not yield a statistically significant difference in the egg masses index compared to the control, a finding which may be attributed to its potentially limited penetrability through the eggshell barrier. Overall, this study has demonstrated that all four nematicides effectively suppress <italic>M. enterolobii</italic> in sweetpotato, and this is the first report on the nematicidal activity of cyclobutrifluram and hymexazol against <italic>M. enterolobii</italic>.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00332024-08-24T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0026<abstract> <title style='display:none'>Abstract</title> <p>Turfgrass is a crop used extensively in athletic fields and golf courses in Maryland. A soil sample collected in July 2023 from an athletic field in Baltimore County, Maryland, part of a turfgrass nematode survey, contained <italic>Belonolaimus longicaudatus</italic>. In the southeastern United States, <italic>B. longicaudatus</italic> is an economically important pathogen of warm season turfgrass. The density was four individuals/100 cm³ of soil, and no visual symptoms were observed in the bermudagrass field. Morphological features and morphometrics of males and females were consistent with <italic>B. longicaudatus</italic> and placed the Maryland population in a subclade that was geographically represented by populations from north and west Florida, Texas, and South Carolina. Sequencing of the internal transcribed spacer region ITS1 and ITS2 and 28S large ribosomal subunit D2-23 expansion region confirmed the species' identity. Phylogenetic trees and parsimony network analysis placed the Maryland isolate in a large grouping of <italic>B. longicaudatus</italic> populations including those from Alabama, Delaware, Florida, Indiana, Mississippi, South Carolina, and Texas. To our knowledge, this is the first report of <italic>B. longicaudatus</italic> in Maryland.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00262024-08-24T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0025<abstract> <title style='display:none'>Abstract</title> <p>Six distinct COI mitochondrial Haplotype Groups (HG) are morphologically, ecologically, and genetically characterized from the aquatic nematode family Tobrilidae. Collection locations included the extreme habitats of the Alkaline Lakes in the western Nebraska Sandhills and the contaminated stream, Johnson Creek, bordering the AltEn 2021 catastrophic pesticide release near the village of Mead in eastern Nebraska. Maximum likelihood and genetic distance metrics supported the genetic integrity of the haplotype groups. Discriminant function analysis of COI haplotype group datasets of combined morphological characters and soil chemistry attributes for both male and female Tobrilidae were classified correctly in all but one case. Scanning electron microscopy revealed new details about amphid apertures, male supplements, and spicules. Partial 18S gene phylogeny suggests that the genus <italic>Semitobrilus</italic> may not be a member of the subfamily Neotobrilinae, and three specimens in the 226 tobrilid dataset provide evidence of incongruence between COI and 18S derived phylogenies. Given the strong signal provided by the environmental chemistry data, tobrilid mitochondrial haplotypes may well have value as environmental indicators.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00252024-08-24T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0030<abstract> <title style='display:none'>Abstract</title> <p>Mexico is the 8^th largest producer of tomatoes. <italic>Meloidogyne enterolobii</italic> is reported in Sinaloa, affecting tomato cultivars with genetic resistance to <italic>Meloidogyne</italic> spp. We aimed to evaluate field applications of fluopyram, fluensulfone, and fluazaindolizine treatments for managing <italic>M. enterolobii</italic> on tomatoes. Experiments were set on raised beds in a shade house. Nematicides were applied via drip irrigation. Under fluopyram treatment, <italic>M. enterolobii</italic> did not reduce the number of extra-large-size fruits. The number of large-size fruits with fluopyram and fluazaindolizine plus fluopyram treatments was also unaffected by <italic>M. enterolobii</italic>. Yield from the treatments fluopyram, fluazaindolizine plus fluopyram, and fluensulfone plus fluopyram was similar to the control treatment without <italic>M. enterolobii</italic>. Finally, fluazaindolizine plus fluopyram, fluopyram, and fluensulfone plus fluopyram treatments showed the highest reduction of root galling. We conclude that the fluopyram was more effective as an individual treatment. Pre-plant applications of fluensulfone and fluazaindolizine reduced the damage to the plant and the loss of yield; however, the complementary application of fluorinated nematicides improved the management of <italic>M. enterolobii</italic> in the tomato crop.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00302024-08-16T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0027<abstract> <title style='display:none'>Abstract</title> <p><italic>Globodera pallida</italic>, the pale cyst nematode, is a quarantined potato pest first found in Idaho in 2006. The containment and eradication of this economically devastating pest has been the focus of control since its discovery. <italic>Globodera pallida</italic> survives for 30+ years in soil and can cause up to 80% yield loss in susceptible potato varieties. Soil fumigants have been key to eradication efforts but many have been banned. Therefore, new control methods are needed. <italic>Solanum sisymbriifolium</italic> induces hatching but limits <italic>G. pallida</italic> reproduction and can be used as an alternative control measure. However, as <italic>S. sisymbriifolium</italic> has little economic value as a crop and its seeds are largely unavailable, it has not been widely adopted by potato producers. There is evidence that this plant kills the nematode by producing toxins, although this is poorly understood. Liquid–liquid extraction of <italic>S. sisymbriifolium</italic> leaf and stem tissues by hexane and 1-butanol reduced hatch by 49.5%, and 68.3%, respectively, compared with the potato root diffusate control. Many chemicals may be responsible for this toxic effect, including steroidal glycoalkaloids produced by plants in the Solanaceae family. The discovery of novel chemistries for nematicide development would be valuable for potato cyst nematode control.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00272024-08-08T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0031<abstract> <title style='display:none'>Abstract</title> <p><italic>Metaparasitylenchus hypothenemi</italic> is an endoparasitic nematode of the coffee berry borer <italic>Hypothenemus hampei</italic>. The nematode has only been recorded across a limited geographical range in coffee-growing areas of southeastern Mexico. Because of its confined geographical distribution, the effect of altitude, temperature, and mean annual precipitation on <italic>M. hypothenemi's</italic> presence/absence in the Soconusco region of Mexico was investigated. The geographical distribution of this parasite was predicted based on current data, using geographical information systems (GIS), the MaxEnt algorithm, and historical data to improve the prediction accuracy for other Neotropical regions. In Soconusco, the presence of this parasite is directly related to annual precipitation, especially in the areas with the highest annual rainfall (4000 – 4700 mm/year). Four species distribution models were generated for the Neotropical region with environmental variables for sites with parasite presence data, predicting a range of possible distribution with a high probability of occurrence in southeastern Mexico and southwestern Guatemala and a low probability in areas of Central and South America. Characterization of the abiotic habitat conditions suitable for <italic>M. hypothenemi</italic> development allows us to predict its distribution in the Neotropics and contributes to our understanding of its ecological relationship with environmental variables.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00312024-08-06T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0023<abstract> <title style='display:none'>Abstract</title> <p>Recombinase polymerase amplification (RPA) is an isothermal <italic>in vitro</italic> nucleic acid amplification technique that has been adopted for simple, robust, rapid, reliable diagnostics of nematodes. In this study, the real-time RPA assay and RPA assay combined with lateral flow dipsticks (LF-RPA) have been developed targeting the ITS rRNA gene of the British root-knot nematode, <italic>Meloidogyne artiellia</italic>. The assay provided specific and rapid detection of this root-knot nematode species from crude nematode extracts without a DNA extraction step with a sensitivity of 0.125 second-stage juvenile (J2) specimen per a reaction tube for real-time RPA during 11 min and a sensitivity of 0.5 J2 specimens per a reaction tube for LF-RPA during 25 min. The RPA assays were validated with a wide range of non-target root-knot nematodes. The LF-RPA assay has great potential for nematode diagnostics in the laboratory having minimal available equipment.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00232024-07-05T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0021<abstract> <title style='display:none'>Abstract</title> <p>From 2016 to 2021, nematode surveys in Florida strawberry fields revealed several species of foliar nematodes (<italic>Aphelenchoides</italic> spp.). <italic>Aphelenchoides besseyi sensu stricto</italic> was detected only in 2016 and 2017 on photosynthetic strawberry leaves/buds, but other not well characterized populations of <italic>Aphelenchoides</italic> sp. were found on declining/dessicated leaves. Morphological analyses showed that these samples of <italic>Aphelenchoides</italic> sp. consisted of <italic>A. bicaudatus</italic>, a species detected in Florida for the first time, and <italic>A. rutgersi</italic>, a species previously reported in Florida from the citrus rhizosphere. These two species differed from <italic>A. besseyi</italic> in the shape of their tail terminus: bifurcate in <italic>A. bicaudatus</italic>; mucronate with a ventral thin mucro in <italic>A. rutgersi</italic>; and stellate in <italic>A. besseyi</italic>. One population each of these species was used for morphological and molecular analyses after being reared on <italic>Monilinia fructicola</italic>. Body and tail length differences were observed among Florida <italic>A. bicaudatus</italic> and other populations from the Far East and South Africa. Phylogenetic analyses of the rRNA gene sequences showed that Florida <italic>A. bicaudatus</italic> grouped with those of species from South Korea, Taiwan, and the Netherlands and several other populations listed as <italic>Aphelenchoides</italic> sp. from Brazil, Costa Rica, and Japan, which were considered as representatives of <italic>A. bicaudatus</italic> in this study. Similarly, sequences of Florida <italic>A. rutgersi</italic> grouped with those from environmental samples in Japan and North Carolina, which were listed as <italic>Aphelenchoides</italic> sp. and were considered as representatives of <italic>A. rutgersi</italic> in this study. Photosynthetic strawberry leaf samples were free from both <italic>A. bicaudatus</italic> and <italic>A. rutgersi</italic>, indicating that these two species did not damage strawberry. They were associated with desiccated leaves and/or propagative stolons, usually infected by fungi, confirming that they are mycetophagous under field conditions in this study. Results of soybean leaf inoculation on moist filter paper containing <italic>A. bicaudatus</italic> specimens showed that this species could become phytophagous under artificial conditions. Nematodes penetrated the leaf epidermis and migrated into the mesophyll causing leaf tissue discoloration/necrosis, which remained localized within the infested area. Soybean leaf damage was almost negligible, and no nematode reproduction was observed in the inoculated soybean areas.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00212024-07-05T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0024<abstract> <title style='display:none'>Abstract</title> <p>Oregon leads the United States in nursery production of shade trees and is third in deciduous and broadleaf evergreen shrub production. Plant-parasitic nematodes have been implicated in problems with the growth of plants in nurseries and are also of phytosanitary risk. A greenhouse experiment was conducted to evaluate the host status of four trees (<italic>Quercus alba, Quercus garryana, Acer campestre, Thuja occidentalis</italic>) and two shrubs <italic>(Buxus sempervirens</italic>, <italic>Rhododendron catawbiense</italic>) to <italic>Meloidogyne incognita, Meloidogyne hapla</italic>, and <italic>Pratylenchus neglectus</italic>. Each plant/nematode treatment was replicated five times, and the experiment was conducted twice. Plants were inoculated with 3,000 eggs of <italic>M. incognita</italic> or <italic>M. hapla</italic> and 2,500 individuals of <italic>P. neglectus</italic> two weeks after planting. After three months, the plants were harvested, and the total density of nematodes in soil and roots for <italic>P. neglectus</italic> and the total density of second-stage juveniles (J2) in soil and eggs on roots for <italic>M. hapla</italic> and <italic>M. incognita</italic> were determined. The final nematode population (Pf) and reproductive factor (RF = Pf/initial population density) were calculated. For <italic>M. incognita</italic> and <italic>M. hapla</italic>, all of the ornamental trees and shrubs would be considered as fair to good hosts with RF values &gt; 1. <italic>Meloidogyne incognita</italic> had the highest Pf (5,234 total J2 and eggs/pot) and RF value (28.4) on <italic>A. campestre</italic>. For <italic>P. neglectus</italic>, all of the ornamental trees and shrubs were fair to good hosts, except for <italic>B. sempervirens</italic>. <italic>Buxus sermpervirens</italic> was not a host for <italic>P. neglectus,</italic> with an RF value of almost 0. This is the first report of <italic>Q. alba, Q. garryana</italic>, and <italic>A. campestre</italic> as hosts for <italic>M. incognita, M. hapla</italic>, and <italic>P. penetrans</italic>. This is also the first report of <italic>T. occidentalis</italic> and <italic>R. catawbiense</italic> as hosts for <italic>P. penetrans</italic> and the non-host status of <italic>B. sermpervirens</italic> for <italic>P. penetrans</italic>.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00242024-06-28T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0019<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>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00192024-06-09T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0022<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>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00222024-05-25T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0016<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>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00162024-05-10T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0020<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>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00202024-05-10T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2024-0018<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>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2024-00182024-05-08T00:00:00.000+00:00en-us-1