RESUMO
Meloidogyne naasi Franklin, 1965, the barley root-knot nematode, was originally found in field crops such as cereals, grasses, and sugar beet (Beta vulgaris L.) in England and Wales, (Franklin,1965). This nematode is one of the most significant root-knot nematodes impacting grains in European countries (Santos et al. 2020). Among root-knot nematode species, M. naasi, exhibits a distinct preference for grasses, with documented impacts on turfgrasses leading to reduced growth and vigor (Skantar et al., 2023; Cook and Yeates, 1993). In September 2022, root-knot nematode females and second-stage juveniles (J2) were recovered from roots of fowl manna grass, Glyceria striata (Lam.) Hitchc., during a nematode survey on natural vegetation at the Allegheny National Forest (41°30'13.8"N 79°09'46.2"W). Second-stage juvenile specimens were recovered from soil using sugar centrifugal flotation (Jenkins, 1964). Small galls with egg masses were dissected from fowl manna grass roots originally collected from the surveyed areas. In parallel, five plants of non-infected fowl manna grass were placed in a pot in the greenhouse using naturally nematode-infested soil collected from the same forested area. Small galls and female specimens recovered from these plants were dissected and processed for further analyses. Female and J2 were fixed in 3% formaldehyde solution and processed to glycerin (Golden, 1990; Hooper, 1970). The specimens were examined by light microscopy, morphometric measurements, and molecular markers, which included the D2-D3 region of the large ribosomal subunit 28S, and the rDNA internal transcribed spacer region (ITS). The perennial pattern of five females analyzed morphologically were consistent to the patterns observed for M. naasi. The perennial patterns had coarse ridges on the cuticle in dorsal region forming broken irregular lines around anal and phasmid area. We also noted a prominent fold that covered some of the anus and showed a curved line between vulval slit and phasmids, typical of M. naasi. The area around the vulval area had a few or no striae except for a few lines radiating from the vulval slit as in the original description. Measurements of ten J2 had a body length ranged between 380 and 410 µm, stylet 11-13 µm, tail 50-70 µm long with a hyaline tail terminus between 12-22 µm in length, 4 lines in the lateral field, a and c ratio between 29.23-35.91 and 5.79-7.9 fitting the original description by Franklin, 1965 and others populations found in the USA (Skantar et al., 2023). The matrix codes for the female specimes are A32, B324, C3, D3 and for J2's A2, B21, C123, D1, E3, F12 (Subbotin et al., 2021). The amplified DNA fragments were sequenced, resulting in an 726 bp fragment flanked by the D2-D3 primers (PP097762), while for the ITS primers an 634 bp fragment was obtained (PP092043). Both generated sequences for the specimens collected in Pennsylvania revealed >99% similarity to M. naasi sequences deposited at GenBank, and therefore, validating the morphological analyses. Based on both morphological and molecular analyses the specimens collected in the state of Pennsylvania were identified as M.naasi. To our knowledge, this is the first report of this species from this state and being associated with naturally infected fowl manna grass.
RESUMO
Barley root-knot nematode, Meloidogyne naasi Franklin, 1965, is one of the most important pest nematodes infecting monocots (Franklin, 1965). Two-inch core soil samples collected from a golf course in Ada County, Idaho were submitted for identification in November of 2019. A high number of Meloidogyne sp. juveniles were recovered from both soil samples using sieving and decantation followed by the sugar centrifugal flotation method. They were examined by light microscopy, morphometric measurements, and multiple molecular markers, including the ribosomal 28S D2-D3 and intergenic spacer 2 (IGS-2) regions, mitochondrial markers cytochrome oxidase I (COI) and the interval from COII to 16S, and the protein-coding gene Hsp90. Morphometrics as well as BlastN comparisons with other root-knot nematode sequences from GenBank were consistent with identification as M. naasi. Phylogenetic trees inferred from 28S, IGS-2, COI, or Hsp90 alignments each separated the Idaho population into a strongly supported clade with other populations of M. naasi, while the COII-16S interval could not resolve M. naasi from M. minor. This report represents the first morphological and molecular characterization of Meloidogyne naasi from turfgrass in Idaho.
RESUMO
Specimens of a tylenchid nematode were recovered in 2019 from soil samples collected from a corn field, located in Pickens County, South Carolina, USA. A moderate number of Tylenchus sp. adults (females and males) were recovered. Extracted nematodes were examined morphologically and molecularly for species identification, which indicated that the specimens of the tylenchid adults were a new species, described herein as Tylenchus zeae n. sp. Morphological examination and the morphometric details of the specimens were very close to the original descriptions of Tylenchus sherianus and T. rex. However, females of the new species can be differentiated from these species by body shape and length, shape of excretory duct, distance between anterior end and esophageal intestinal valve, and a few other characteristics given in the diagnosis. Males of the new species can be differentiated from the two closely related species by tail, spicules, and gubernaculum length. Cryo-scanning electron microscopy confirmed head bearing five or six annules; four to six cephalic sensilla represented by small pits at the rounded corners of the labial plate; a small, round oral plate; and a large, pit-like amphidial opening confined to the labial plate and extending three to four annules beyond it. Phylogenetic analysis of 18S rRNA gene sequences placed Tylenchus zeae n. sp. in a clade with Tylenchus arcuatus and several Filenchus spp., and the mitochondrial cytochrome oxidase c subunit 1 (COI) gene region separated the new species from T. arcuatus and other tylenchid species. In the 28S tree, T. zeae n. sp. showed a high level of sequence divergence and was positioned outside of the main Tylenchus-Filenchus clade.
RESUMO
The North American beech leaf disease (BLD) nematode, Litylenchus crenatae mccannii Handoo, Li, Kantor, Bauchan, McCann, Gabriel, Yu, Reed, Koch, Martin and Burke, 2020, is recognized as a newly emergent nematode species that causes BLD in beech trees (Fagus spp.) in North America (Carta et al. 2020; Kantor et al. 2022a). Since the first report of BLD on American beech (Fagus grandifolia Ehrh) within the Lake County, located at the north-eastern corner of the state of Ohio in 2012 (Carta et al. 2020), the disease has rapidly spread to other US states and a province in Canada (Erwing et al. 2018; Carta et al 2020; Marra and LaMondia 2020; Reed et al 2020; Kantor et al. 2022b). Currently, besides Ohio, this nematode has been reported in Pennsylvania, New York, Connecticut, Massachusetts, Maine, Rhode Island, New Jersey, West Virginia, and Virginia, as well as Ontario, Canada. Different life stages of L. crenatae mccannii were isolated from symptomatic American beech leaves from an isolated natural maple-beech stand in rural Saint Clair Cty., Michigan, US; presenting typical symptoms of beech leaf disease, i.e., swelling and darkening of interveinal leaf tissues. Samples were taken to the Forest Pathology Laboratory at Michigan State University where L. crenatae mccannii presence was confirmed in the leaves after which samples were sent to the Mycology and Nematology Genetic Diversity and Biology Laboratory (USDA-ARS) in Beltsville, Maryland for official confirmation. Nematodes were identified based on morphology and sequence analysis of the internal transcribed spacer (ITS), and the D2D3 region of the 28S large subunit ribosomal DNA. To validate the morphological identification two different ribosomal DNA loci were amplified, sequenced and the phylogenetic relationships were generated. The amplification yielded fragments of 784 and 741 bp flanked by the ITS (GenBank accession no. OP689654) and D2D3 (GenBank accession no. OP689710) primers, respectively. The sequences obtained for the specimens collected in Michigan revealed 100% similarity to L. crenatae mccannii sequences obtained from specimens collected from other geographical areas in the US, and therefore validating the morphological analyses as well. The ITS sequence shared a 99.75% similarity with the subspecies L. crenatae (GenBank accession no. LC383724.1), and 90.53% similarity to L. coprosma Zhao, Davies, Alexander and Riley, 2011 (GU727548.1). While the D2D3 sequences of both L. crenatae subspecies revealed a 100% similarity (versus LC383725.1), they revealed 95.35% similarity to L. coprosma (KY679564.1). Since the first confirmed detection of BLD in June 2022 in St. Clair Cty, BLD has been reported in Oakland and Wayne Ctys (7 reports total across the three counties), suggesting BLD spread in the SE of Michigan. BLD confirmation was based on either physical symptoms (leaf banding), and/or the presence of the beech leaf nematode by morphological or molecular confirmation. The presence of the beech leaf nematode in symptomatic leaves follow the results obtained by Carta et al. (2020) after inoculation of beech seedlings with L. crenatae mccannii. Based on both morphological and molecular analyses the specimens collected in the state of Michigan were identified as L. crenatae mccannii. To our knowledge, this is the first report of this species in conjunction with symptomatic F. grandifolia leaves in this state.
RESUMO
Sauertylenchus maximus was discovered during a survey conducted at the Arlington National Cemetery, Virginia, for the type specimens of Hoplolaimus galeatus. Besides the fresh material, the fixed specimens of S. maximus were also studied by molecular and morphological means. The morphological and morphometric characteristics of the recovered fresh material were consistent with the original and other description(s) of this species. The fixed specimens used in this study were preserved in a 3% formaldehyde and 2% glycerin solution for over 20 yr. Molecular analyses of the fresh and fixed specimens were performed using internal transcribed spacer, D2-D2 expansion segments of 28S large subunits, and 18S small subunit ribosomal DNA sequences. To our knowledge, this represents the first report of S. maximus from Virginia and the first report of a successful DNA extraction from fixed nematode specimens.
RESUMO
In August of 2021, several cysts with juveniles and eggs were discovered during a vegetation survey conducted at the Arlington National Cemetery, Virginia. Eight soil samples were collected from the rhizosphere region of the common grass (Festuca arundinacea L.) and processed at the Mycology and Nematology Genetic Diversity and Biology Laboratory (MNGDBL). Cysts were light to dark brown in color, and oval to pear-shaped without bullae in young cysts but present in older cysts and with prominent vulval cone. The juveniles had slightly concave stylet knobs projecting sometimes anteriorly, tail tapering gradually to a narrowly rounded terminus, and hyaline tail terminus conspicuous at least twice the length of stylet. The molecular analysis included the analysis of three gene sequence fragments: D2-D3 of 28S rRNA, ITS rRNA, and COI. The nematode species was identified by both morphological and molecular means as Stone's cyst nematode, Punctodera stonei. Detection of P. stonei in Virginia represents a new record of this species in the United States, and a second report after Canada in North America.
RESUMO
The pin nematode, Paratylechus beltsvillensis n. sp. collected from rhizosphere soil of a Virginia pine tree (Pinus virginiana Mill) growing in Little Paint Branch Park, Beltsville, Prince George's County, Maryland, USA, is described and illustrated along with light and scanning electron photomicrographs. Females, males, and juveniles of this new species were recovered from soil samples using the sugar centrifugal flotation and Baermann funnel extraction methods. Morphologically, females are short, body length ranging from 245 to 267 µm, stylet from 70 to 75 µm long with anchor shaped knobs, vulva located at 70-73% and small vulval flap, spermatheca large, and ovoid filled with sperms. Lateral field with three incisures, of which the outer two are prominent. Tail slender, having a rounded tail terminus. Males without stylet and have a degenerated pharynx, spicules = 17-20 µm and gubernaculum = 5.0-5.5 µm. Both morphological observations and molecular analysis of ITS and partial 28S ribosomal RNA gene sequences indicated that the specimens collected from the soil at Beltsville Park from rhizosphere soil samples from Virginia pine represents a new pin nematode species.
RESUMO
In 2019, Cactodera milleri cysts were discovered from soil samples collected from a Chenopodium quinoa field, located in Mosca, Alamosa county, Colorado, USA. Approximately 200 lemon shaped cysts and several hundred juveniles were recovered from the affected quinoa plants. The same species was also identified from several counties in Minnesota from samples submitted over the years by the Minnesota Department of Agriculture as part of the Animal and Plant Health Inspection Service (APHIS) efforts to survey states for the presence of Pale Potato Cyst Nematode. The cysts and juveniles (J2) were recovered from soil samples through sieving and Baermann funnel extraction. The nematode species was identified by both morphological and molecular means as Cactodera milleri (Graney and Bird, 1990). To our knowledge this represents the first report of Cactodera milleri from Colorado and Minnesota.
RESUMO
A high number of second stage juveniles of the root-knot nematode were recovered from soil samples collected from a corn field, located in Pickens County, South Carolina, USA in 2019. Extracted nematodes were examined morphologically and molecularly for species identification which indicated that the specimens of root knot juveniles were Meloidogyne hispanica. The morphological examination and morphometric details from second-stage juveniles were consistent with the original description and redescriptions of this species. The ITS rRNA, D2-D3 expansion segments of 28S rRNA, intergenic COII-16S region, nad5 and COI gene sequences were obtained from the South Carolina population of M. hispanica. Phylogenetic analysis of the intergenic COII-16S region of mtDNA gene sequence alignment using statistical parsimony showed that the South Carolina population clustered with Meloidogyne hispanica from Portugal and Australia. To our best knowledge, this finding represents the first report of Meloidogyne hispanica in the USA and North America.
RESUMO
Cactodera torreyanae Cid del Prado Vera & Subbotin, 2014 cysts were discovered during a Pale Potato Cyst Nematode (PCN) survey conducted by Minnesota Department of Agriculture as part of the Animal and Plant Health Inspection Service (APHIS) efforts to survey states for the presence of PCN. The soil samples were collected from a potato field, located in Karlstad, Kittson County, Minnesota, USA. Two out of 175 vials submitted for identification to the Mycology and Nematology Genetic Diversity and Biology Laboratory (MNGDBL) contained few cysts and juveniles of C. torreyanae. Cysts were dark brown in color, lemon-shaped to elongated with distinct vulval cone. Vulva with denticles present around fenestra, cyst length to width ratio between 1.6 and 2.3 and anus distinct. The juveniles had rounded stylet knobs, some sloping slightly posteriorly. The molecular analysis included sequence and phylogenetic analysis of ITS rRNA, D2-D3 expansion segments of 28S rRNA and COI of mtDNA genes. The nematode species was identified by both morphological and molecular means as Cactodera torreyanae. To the best of our knowledge this represents the first report of Cactodera torreyanae from the United States and first report of this cyst nematode species from potato fields. Definite host plant for this nematode remains unknown.
RESUMO
Chia (Salvia hispanica L.) seeds are used for food, drinks, oil, and animal feed, and all plant parts are employed in traditional medicine. The growing demand for the seed has created a need for improved disease management. Plant-parasitic nematodes have been found on other Salvia spp., but none have been reported from S. hispanica. Chia has also not been tested for production of compounds active against these nematodes. Therefore, aqueous extracts from shoots and roots of six chia lines, Brad's Organic, Cono, E2, G3, G5, and W13.1, were tested in laboratory assays. Some concentrations of all extracts were nematotoxic, killing about one-third of Meloidogyne incognita (Kofoid & White) Chitwood second-stage juveniles (J2s) in shoot extracts and up to nearly half of J2s in root extracts. Hatch was generally not affected by the extracts. In greenhouse trials, all six chia lines were hosts of M. incognita. Chia line G3 had approximately two times or more eggs per gram of root than Brad's Organic or Cono. When cucumber seedlings were transplanted into soil amended with chopped chia shoots (2.3 or 2.5% weight of fresh shoots/weight of dry soil), galling and egg production on cucumber roots were not suppressed. To our knowledge, this is the first report that chia is a host to M. incognita (or any phytoparasitic nematode) and that chia shoots and roots produce compounds active against a nematode.
Assuntos
Cucumis sativus , Tylenchida , Tylenchoidea , Animais , Extratos Vegetais/farmacologia , SementesRESUMO
In this study, molecular characterization of Paratylenchus nanus collected from the type locality in Four Mile Run, Fall Church, Virginia using COI, D2-D3 of 28 S rRNA and ITS rRNA gene sequences was provided. We molecularly also characterized, Paratylenchus specimens collected from grasses in Devils Lake, Ramsey County, North Dakota indicated as the type locality in the original description of P. nanus by Cobb (1923). These nematodes were identified as representatives of the species P. projectus. Populations of P. nanus belonging to the molecular types A and B, and previously designated by Van den Berg et al. (2014) should be now identified as P. nanus and P. projectus, respectively.
RESUMO
In the summer of 2016, a field of corn (Zea mays) in Spencer County, Indiana was observed with heavily stunted plants, and from the affected roots a large number of cysts were recovered. Soil samples were submitted to one of us (JF), who extracted the nematode cysts and sent them to the USDA-ARS, Mycology and Nematology Genetic Diversity and Biology Laboratory (MNGDBL), Beltsville, MD for morphological and molecular identification. Cysts and the recovered second-stage juveniles (J2) that were examined morphologically conformed to the measurements of Vittatidera zeaphila, the goose cyst nematode originally described from Tennessee, USA in 2010. The molecular analysis of J2 showed the sample from Spencer County matched exactly with V. zeaphila according to ribosomal DNA markers ITS, 28S, and 18S, and with mitochondrial cytochrome oxidase I (COI). The nuclear marker heat shock protein 90 (Hsp90) was also analyzed for the first time from the Indiana population of V. zeaphila. Similarities to existing cyst nematode sequences are reported herein. Geographically, although the county is across the Ohio River from Kentucky, the previously reported Hickman County, Kentucky location and Indiana detection are approximately 200 miles apart. To the best of our knowledge, this is the first report of V. zeaphila in Indiana.In the summer of 2016, a field of corn (Zea mays) in Spencer County, Indiana was observed with heavily stunted plants, and from the affected roots a large number of cysts were recovered. Soil samples were submitted to one of us (JF), who extracted the nematode cysts and sent them to the USDA-ARS, Mycology and Nematology Genetic Diversity and Biology Laboratory (MNGDBL), Beltsville, MD for morphological and molecular identification. Cysts and the recovered second-stage juveniles (J2) that were examined morphologically conformed to the measurements of Vittatidera zeaphila, the goose cyst nematode originally described from Tennessee, USA in 2010. The molecular analysis of J2 showed the sample from Spencer County matched exactly with V. zeaphila according to ribosomal DNA markers ITS, 28S, and 18S, and with mitochondrial cytochrome oxidase I (COI). The nuclear marker heat shock protein 90 (Hsp90) was also analyzed for the first time from the Indiana population of V. zeaphila. Similarities to existing cyst nematode sequences are reported herein. Geographically, although the county is across the Ohio River from Kentucky, the previously reported Hickman County, Kentucky location and Indiana detection are approximately 200 miles apart. To the best of our knowledge, this is the first report of V. zeaphila in Indiana.
RESUMO
Root-lesion nematodes (Pratylenchus spp.) are among the most important nematode pests on grapevine along with root-knot, dagger, and ring nematodes. In 2019, two samples of both soil and roots were collected from a vineyard in Delano, Kern County, California and submitted to the United States Department of Agriculture, ARS, Mycology and Nematology Genetic Diversity and Biology Laboratory, Beltsville, MD, for identification purposes. Females and juveniles of Pratylenchus sp. were recovered from the root and soil samples using the sugar centrifugal flotation and Baermann funnel extraction methods. Both morphological observations and molecular analysis of internal transcribed spacer (ITS), 28S large subunit ribosomal DNA, and mitochondrial cytochrome oxidase (COI) sequences indicated that the specimens recovered from the soil and roots were Pratylenchus hippeastri. To the best of the authors' knowledge, this is the first report of P. hippeastri from California including the first record of this species on grapevine and the second state record in North America. Damages caused by nematodes cannot be over-emphasized, although economic importance of P. hippeastri has never been established. Hence, there is an urgent need to investigate the economic impact of this nematode in vineyards in California State in order to develop sustainable management strategies.Root-lesion nematodes (Pratylenchus spp.) are among the most important nematode pests on grapevine along with root-knot, dagger, and ring nematodes. In 2019, two samples of both soil and roots were collected from a vineyard in Delano, Kern County, California and submitted to the United States Department of Agriculture, ARS, Mycology and Nematology Genetic Diversity and Biology Laboratory, Beltsville, MD, for identification purposes. Females and juveniles of Pratylenchus sp. were recovered from the root and soil samples using the sugar centrifugal flotation and Baermann funnel extraction methods. Both morphological observations and molecular analysis of internal transcribed spacer (ITS), 28S large subunit ribosomal DNA, and mitochondrial cytochrome oxidase (COI) sequences indicated that the specimens recovered from the soil and roots were Pratylenchus hippeastri. To the best of the authors' knowledge, this is the first report of P. hippeastri from California including the first record of this species on grapevine and the second state record in North America. Damages caused by nematodes cannot be over-emphasized, although economic importance of P. hippeastri has never been established. Hence, there is an urgent need to investigate the economic impact of this nematode in vineyards in California State in order to develop sustainable management strategies.
RESUMO
In the spring of 2019, a cyst nematode was discovered from soil samples collected from an alfalfa field in Millard County, Utah. The soil samples were submitted to one of us (SH), who extracted the nematode cysts and sent them to the USDA-ARS, Mycology and Nematology Genetic Diversity and Biology Laboratory (MNGDBL), Beltsville, MD for morphological and molecular identification. Cysts and living nematode juveniles (J2) recovered from the cysts were examined morphologically and molecularly for species identification which indicated that the specimens were Heterodera medicaginis. This represents the first record of H. medicaginis in Utah and the second report of this nematode in North America.In the spring of 2019, a cyst nematode was discovered from soil samples collected from an alfalfa field in Millard County, Utah. The soil samples were submitted to one of us (SH), who extracted the nematode cysts and sent them to the USDA-ARS, Mycology and Nematology Genetic Diversity and Biology Laboratory (MNGDBL), Beltsville, MD for morphological and molecular identification. Cysts and living nematode juveniles (J2) recovered from the cysts were examined morphologically and molecularly for species identification which indicated that the specimens were Heterodera medicaginis. This represents the first record of H. medicaginis in Utah and the second report of this nematode in North America.
RESUMO
Festulolium hybrids are forage grasses used worldwide in temperate climates. They are associated with the fungal endophyte Epichloë uncinata, which aids in nutrient uptake, drought tolerance, and production of metabolites that protect against parasites and herbivores. Epichloë uncinata produces loline alkaloids, which can deter insect pests. Festulolium has not been widely studied for susceptibility to plant-parasitic nematodes, so Festulolium lines, with and without fungal endophytes, were tested in the greenhouse for host status to the root-knot nematode Meloidogyne incognita. All were poor hosts, regardless of line or endophyte status. Pepper seedlings planted into soil following removal of the Festulolium plants were infected by nematodes, likely because of surviving nematodes from the original inoculation combined with some reproduction on Festulolium. Lolines were found in shoots and roots of all endophyte-associated lines, and some types of lolines in roots increased after nematode infection. Methanolic extracts from roots and shoots of a tested Festulolium line did not inhibit egg hatch, but killed nearly a third of second-stage juveniles whether an endophyte was present or not. Further studies would indicate whether these Festulolium lines aid in suppressing field populations of M. incognita.Festulolium hybrids are forage grasses used worldwide in temperate climates. They are associated with the fungal endophyte Epichloë uncinata, which aids in nutrient uptake, drought tolerance, and production of metabolites that protect against parasites and herbivores. Epichloë uncinata produces loline alkaloids, which can deter insect pests. Festulolium has not been widely studied for susceptibility to plant-parasitic nematodes, so Festulolium lines, with and without fungal endophytes, were tested in the greenhouse for host status to the root-knot nematode Meloidogyne incognita. All were poor hosts, regardless of line or endophyte status. Pepper seedlings planted into soil following removal of the Festulolium plants were infected by nematodes, likely because of surviving nematodes from the original inoculation combined with some reproduction on Festulolium. Lolines were found in shoots and roots of all endophyte-associated lines, and some types of lolines in roots increased after nematode infection. Methanolic extracts from roots and shoots of a tested Festulolium line did not inhibit egg hatch, but killed nearly a third of second-stage juveniles whether an endophyte was present or not. Further studies would indicate whether these Festulolium lines aid in suppressing field populations of M. incognita.
RESUMO
In April 2018, a cyst nematode was discovered from soil samples collected from a cactus garden collection in Meridian, Ada County, Idaho, USA. The cactus garden collection field reported was observed with localized areas of heavily stunted plants. Roots from affected plants displayed moderate numbers of nematode cysts. Living nematode juveniles (J2) recovered from the cysts were examined morphologically and molecularly for species identification which indicated that the specimens were Cactodera cacti. This is the first report of the cactus cyst nematode, C. cacti in Idaho.In April 2018, a cyst nematode was discovered from soil samples collected from a cactus garden collection in Meridian, Ada County, Idaho, USA. The cactus garden collection field reported was observed with localized areas of heavily stunted plants. Roots from affected plants displayed moderate numbers of nematode cysts. Living nematode juveniles (J2) recovered from the cysts were examined morphologically and molecularly for species identification which indicated that the specimens were Cactodera cacti. This is the first report of the cactus cyst nematode, C. cacti in Idaho.
RESUMO
The United States Department of Agriculture Nematode Collection (USDANC) is one of the largest and most valuable in existence and includes millions of specimens housed in over 39,800 permanent slides and 9,300 vials. This collection preserves type specimens of nematodes to serve as a reference for identifications and future taxonomic revisions. Also, the collection provides useful information on nematode hosts, occurrence, and distribution. The present list includes type specimens added to the USDANC since 1998. Since that time, the collection has expanded, with 474 type species mounted and preserved on 2,564 glass slides and 180 vials. We encourage nematologists throughout the world to deposit type specimens in the USDANC for use by future generations.
RESUMO
Citrullus amarus ( CA ) (previously known as Citrullus lanatus var. citroides ) accessions collected in southern Africa are known to have resistance to root-knot nematodes (RKN) and are suitable rootstocks for grafted watermelon. The objective of this study was to conduct a comparative metabolomics analysis and identify unique metabolites in roots of CA accessions versus roots of watermelon cultivars ( Citrullus lanatus (Thunb.) Matsum. and Nakai var. lanatus; CL ). Nuclear magnetic resonance (NMR) technology and principal component analysis (PCA) were used to analyze and compare metabolic profiles of seven CA accessions resistant to RKN along with two RKN-susceptible watermelon cultivars (Charleston Gray and Crimson Sweet). Calculation of the Mahalanobis distance revealed that the CA United States Plant Introduction (PI) 189225 (Line number 1832) and PI 482324 (1849) have the most distinct metabolic profiles compared with the watermelon cultivars Charleston Gray and Crimson Sweet, respectively. Several amino acids identified in the CA accessions were reported in previous studies to have a nematicidal effect. The results in this study indicate that roots of watermelon accessions collected in the wild are rich in metabolic compounds. These metabolic compounds may have been diminished in watermelon cultivars as a consequence of many years of cultivation and selection for desirable fruit qualities.
RESUMO
Biosecurity in agriculture is essential for preventing the introduction and spread of plant-parasitic nematodes (PPNs) which threaten global food security by reducing crop yields and facilitating disease spread. These risks are exacerbated by increased global trade and climate change, which may alter PPN distribution and activity, increasing their impact on agricultural systems. Addressing these challenges is vital to maintaining the integrity of the food supply chain. This review highlights significant advancements in managing PPN-related biosecurity risks within the food supply chain, particularly considering climate change's evolving influence. It discusses the PPN modes of transmission, factors increasing the risk of infestation, the impact of PPNs on food safety and security, and traditional and emerging approaches for detecting and managing these pests. Literature suggests that implementing advanced biosecurity measures could decrease PPN infestation rates by up to 70%, substantially reducing crop yield losses and bolstering food security. Notably, the adoption of modern detection and management techniques, (molecular diagnostics and integrated pest management) and emerging geospatial surveillance and analysis systems (spectral imaging, change-detection analysis) has shown greater effectiveness than traditional methods. These innovations offer promising avenues for enhancing crop health and securing the food supply chain against environmental shifts. The integration of these strategies is crucial, demonstrating the potential to transform biosecurity practices and sustain agricultural productivity in the face of changing climatic conditions. This analysis emphasizes the importance of adopting advanced measures to protect crop health and ensure food supply chain resilience, providing valuable insights for stakeholders across the agricultural sector.