Explore the vast range of titles available.

Lance nematodes (Hoplolaimus spp.) feed on the roots of a wide range of plants, some of which are agronomic crops. Morphometric values of amphimictic lance nematode species overlap considerably, and useful morphological characters for their discrimination require high magnification and significant diagnostic time. Given their morphological similarity, these Hoplolaimus species provide an interesting model to investigate hidden diversity in crop agroecosystems. In this scenario, H. galeatus may have been over‐reported and the related species that are morphologically similar could be more widespread in the United States that has been recognized thus far. The main objectives of this study were to delimit Hoplolaimus galeatus and morphologically similar species using morphology, phylogeny, and a barcoding approach, and to estimate the genetic diversity and population structure of the species found. Molecular analyses were performed using sequences of the cytochrome c oxidase subunit 1 (Cox1) and the internal transcribed spacer (ITS1) on 23 populations. Four morphospecies were identified: H. galeatus, H. magnistylus, H. concaudajuvencus, and H. stephanus, along with a currently undescribed species. Pronounced genetic structure correlated with geographic origin was found for all species, except for H. galeatus. Hoplolaimus galeatus also exhibited low genetic diversity and the shortest genetic distances among populations. In contrast, H. stephanus, the species with the fewest reports from agricultural soils, was the most common and diverse species found. Results of this project may lead to better delimitation of lance nematode species in the United States by contributing to the understanding the diversity within this group. The main objectives of this study were to delimit Hoplolaimus galeatus and morphologically similar species by using morphology, phylogeny and a barcoding approach, and to estimate the genetic diversity and population structure of the species found. Four morphospecies were identified: H. galeatus, H. magnistylus, H. concaudajuvencus, and H. stephanus along with a currently undescribed species. Pronounced genetic structure correlated with geographical origin was found for all species, except for H. galeatus. H. stephanus, the species with the fewest reports from agricultural soils, was the most common and diverse species found.

Nematode infections cause severe damage to crops like eggplants. Information on the effects of nematodes on scarlet eggplant is rare. This study investigated the effect of soil amendments on soil nematodes population densities under garden eggplants. The completely randomized block design with replicated treatments was utilized. The trials were conducted in a field infested with four nematode species: Meloidogyne, Hoplolaimus, Helicotylenchus, and Pratylenchus. Number of nematodes per plot were extracted, plant height was measured with tape, and number of leaves were counted. Biochar (10 tons ha-1 (100%)) excelled in the control of these nematodes, followed by cow dung (100%) and Bauhinia purpurea (100%), then cow dung (5 tons ha-1 (50%)), and Bauhinia sp. (50%). Hoplolaimus sp. multiplied or survived most, particularly on biochar (50%) followed by Pratylenchus sp. on Bauhinia sp. (50%). All treatments had similar nematode populations. At 3 weeks after transplanting (WAT), cow dung 50%, Bauhinia sp. 100%, and Bauhinia sp. 50% induced the production of taller plants than the control. At 5 WAT, cow dung 50% was the best material for producing taller plants followed by Bauhinia sp. 100% and Bauhinia sp. 50% then biochar (50 and 100%). At 3 WAT, all organic control agents performed better than control, except for biochar. At 4 WAT, all the organic control agents except biochar 50% performed better than control. Finally, at 5 WAT best control material was cow dung 100% followed by Bauhinia sp. (100%), Bauhinia sp. (50%), biochar (100%), and cow dung (50%). These amendments are all recommended.

Lance nematodes (Hoplolaimus spp.) feed on the roots of various plants, including key horticultural products. An investigation of the genetic diversity and structure of six Hoplolaimus species, utilizing the cytochrome c oxidase I (COI) of the mtDNA gene, was based on 174 sequences available on the NCBI. Based on the COI of mtDNA, the haplotype analysis revealed 44 haplotypes. Nucleotide diversity was low among all species of Hoplolaimus, except for H. magnistylus (π = 0.04915) and H. stephanus (π = 0.06746). In contrast, haplotype diversity (Hd) was high, especially for H. stephanus (Hd = 0.89) and H. pararobustus (Hd = 0.90). Phylogenetic analysis grouped the various populations into eight clades, and the result showed that H. magnistylus was placed in three different clades, which showed high variability in haplotype supported by the haplotype network. Neutrality tests and mismatch distribution based on the mtDNA supported the hypothesis of a constant population with no expansion in Hoplolaimus, except for H. concaudajuvencus (Tajima (D) = −0.84971) and H. columbus (Tajima (D) = −0.87674). In conclusion, genetic analysis showed a neutral evolution amongst the Hoplolaimus species. The result of the present study provides a better insight into the Hoplolaimus species toward species delimitation and managing this plant-parasitic nematode in various crops.

We sampled 127 turfgrass soil samples from 33 golf courses in NC, EC, and SC for plant-parasitic nematodes (PPNs). PPNs were extracted from soil samples using the shallow dish method and were identified at the genus or species levels with a combination of morphological and molecular methods. The results revealed 41 species of nematode belonging to 20 genera and 10 families. Nine genera are new records of PPNs associated with turfgrass in China. The PPNs show strong geographical distributions. Of the 20 genera, Helicotylenchus, Paratrichodorus, Hoplolaimus, Meloidogyne, Hemicriconemoides, and Mesocriconema showed higher infestation and frequency, and most of these genera had numbers in soil samples above established damage thresholds. Four golf courses had soil samples with PPNs > 30%, indicating the potential for nematode damage. The biodiversity indices H’, SR, J’, λ, and H2 showed significant differences among different regions and turfgrass species; H’, SR, J’, and H2 were significantly higher in EC than in NC and SC, while λ was lowest in EC. Creeping bentgrass had the highest H’, SR, J’, and H2 and the lowest λ in comparison with seashore paspalum and hybrid bermudagrass. These findings provide baseline information on the occurrence of turfgrass-associated PPNs in China, and have important implications for the effective management of PPNs causing damage on turfgrass.

In Wonji‐Shoa Sugar Estate (WSSE), sugarcane (Saccharum spp. hybrid) yields have declined by about 48% over the last 70 years. One of the causes for the decline is assumed to be the long‐term monoculture production system that results in the buildup of plant parasitic nematodes (PPNs). Therefore, the population and diversity of PPNs were investigated by conducting soil sampling using a biosequential method (simultaneous sampling of the soils of adjacent cultivated land [CL] and uncultivated land [UL]) and a chronosequential method (taking soil samples at different times from the same site). The samples were subjected to analysis using standard procedures to determine the change in the population, and identify the genera of PPNs. Additionally, a pot experiment that involved fumigation was conducted on top soils sampled from the CL and UL of the plantation. The results revealed that about 10 genera of PPNs (Meloidogyne, Helicotylenchus, Hoplolaimus, Rotylenchulus, Hemicycliophora, Discriconemella, Xhiphinema, Pratylenchus, Tylenchorhynchus, and Scutellonema) were detected, of which the first four were newly identified. The population density and the number of genera of PPNs found in the CL were 36‐fold and 4.5‐fold higher than those found in the UL, respectively. Furthermore, fumigation reduced the population of the PPNs by 61% and increased production of cane biomass by 63%. It is concluded that the soils of the WSSE are infested by PPNs, which consequently have detrimental effects on sugarcane growth. While amending soil fertility is crucial, reversing the decline in sugarcane yields also necessitates implementing an integrated soil management system that includes PPNs. Core Ideas Ten plant parasitic nematodes (PPNs) were identified in the study area. The two most destructive PPNs of sugarcane, that is, Pratylenchus and Melodogyne, were among the identified ones. The population and the diversity of PPNs were increased with time. Long‐term monoculture system was the major reason for the build of PPNs. The buildup of the PPNs contributed to the yield decline encountered by Wonji‐Shoa Sugarcane Plantation.

is a plant-parasite nematode with a broad range of hosts. This nematode is known to damage cotton, corn, and soybean crops. is also an economically important pest of turfgrasses. Despite its economical importance, no genomic resources exist for this parasite. Using 300 bp paired-end short read sequencing, this study estimated genome size, analyzed a nearly complete mitochondrial chromosome, and explored nuclear repetitive elements, including microsatellites, in for the first time. The phylogenetic placement of in the superfamily Tylenchoidea was also examined. The average haploid genome size estimated using a k-mer approach was 517.69 Mbp. The partially assembled mitochondrial genome of is 16,578 bp in length and comprised of 11 protein-coding genes, two ribosomal RNA genes, and 16 transfer RNA genes. A maximum likelihood phylogenetic analysis confirmed the monophyly of the genus and the superfamily Tylenchoidea. Repetitive elements constituted  50% of the nuclear genome while half of the genome represented single- or low-copy sequences. A large portion of repetitive sequences could not be assigned to known repeat element families. Considering only annotated repetitive elements, the most ubiquitous belonged to Class II- Subclass 2-Maverick elements, Class I-LTR-Ty-3/Bel-Pao elements, and satellites. 45S ribosomal DNA was also abundant and a total of 36 SSRs were identified.This study developed genomic resources for the plant-parasitic nematode that will contribute to the better understanding of meta-population connectivity and putative genomic mechanisms involved in the exploitation of the broad range of host plants used by .

Background The plant-parasitic nematode Hoplolaimus columbus is a pathogen that uses a wide range of hosts and causes substantial yield loss in agricultural fields in North America. This study describes, for the first time, the complete mitochondrial genome of H. columbus from South Carolina, USA. Methods The mitogenome of H. columbus was assembled from Illumina 300 bp pair-end reads. It was annotated and compared to other published mitogenomes of plant-parasitic nematodes in the superfamily Tylenchoidea. The phylogenetic relationships between H. columbus and other 6 genera of plant-parasitic nematodes were examined using protein-coding genes (PCGs). Results The mitogenome of H. columbus is a circular AT-rich DNA molecule 25,228 bp in length. The annotation result comprises 12 PCGs, 2 ribosomal RNA genes, and 19 transfer RNA genes. No atp8 gene was found in the mitogenome of H. columbus but long non-coding regions were observed in agreement to that reported for other plant-parasitic nematodes. The mitogenomic phylogeny of plant-parasitic nematodes in the superfamily Tylenchoidea agreed with previous molecular phylogenies. Mitochondrial gene synteny in H. columbus was unique but similar to that reported for other closely related species. Conclusions The mitogenome of H. columbus is unique within the superfamily Tylenchoidea but exhibits similarities in both gene content and synteny to other closely related nematodes. Among others, this new resource will facilitate population genomic studies in lance nematodes from North America and beyond.

The EFSA Panel on Plant Health performed a pest categorisation of Hoplolaimus galeatus (Nematoda: Hoplolaimidae) for the EU. H. galeatus belongs to the order Rhabditida, subfamily Hoplolaiminae. This nematode is not reported from the EU and is not included in the EU Commission Implementing Regulation 2019/2072. It is widely distributed in the USA and is also reported from South America, Africa, Asia and Australia. The identity of H. galeatus is clearly defined and methods for its identification are available. H. galeatus is polyphagous and natural hosts include barley, wheat, rye, red and white clover, alfalfa, cabbage, pine, spruce, oak, apple, grapevine, as well as various ornamental plants and turf grasses. These hosts are grown over vast areas of the EU. The climate of the EU is suitable for the establishment of H. galeatus. Pathways of entry are host plants for planting except seeds, but also soil as a contaminant. Soil import to the EU is prohibited and special requirements apply to import of machinery for agricultural/forestry purposes from third countries. Impact of the nematode is best known for North American plant species. The nematode has been reported to damage cotton, maize, soybean, pine, oak and turfgrass. Many of the hosts represent a considerable economic and environmental value to the EU. Therefore, the Panel concludes that H. galeatus satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

A quantitative PCR procedure targeting the Heterodera glycines ortholog of the Caenorhabditis elegans uncoordinated-78 gene was developed. The procedure estimated the quantity of H. glycines from metagenomic DNA samples isolated directly from field soil under agronomic production. The estimation of H. glycines quantity was determined in soil samples having other soil dwelling plant parasitic nematodes including Hoplolaimus, predatory nematodes including Mononchus, free-living nematodes and biomass. The methodology provides a framework for molecular diagnostics of nematodes from metagenomic DNA isolated directly from field soil.

Plant parasitic nematode population densities were determined from 325 root and soil samples collected from vegetable growing areas in Pakistan. Yield losses associated with nematode presence were quantified on 19 vegetable crops during 2007 and 2009. The most abundant plant-parasitic nematodes detected, in order of decreasing frequency of infestation (percentage of samples), were Meloidogyne incognita (90%), Pratylenchus penetrans (30.2%), Tylenehorhynchus clarus (29%), Hoplolaimus columbus (15%), Paratrichodorus minor (7.5%), Xiphinema americanum (7.1 %), M. javanica (7%), Belonolaimus longicaudatus (5.6%), Longidorus africanus (5%), and Helicotylenchus dihystera (3.2%). We observed ca 23% yield losses ranged from 2% for cabbage to 45% for squash, which is 35%, 80%, and 46% higher compared to developed countries, USA, and India, respectively. The main reason for more losses in Pakistan might be related to incognizant growers about the presence or nematodes and the damage they cause. Another reason might be non-availability of resistant crop cultivars and nematicides. Another possibility is that on small-sized farms with varied cropping histories and inattention to the pest-host-status one result appears to be a larger list of available nematode species, compared to farming practices in USA where only one or two nematode species become dominant. This study provides important information for extension specialists and creates awareness among growers about these hidden crop enemies. It also suggests the need for improved management measures to avoid crop losses.