is a free-living nematode that shares many features with , 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 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 PS1843 genome and the genome of the 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.

Based on molecular markers, mating experiments, morphological observations and ecological data, two 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 clade. 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. n. sp. is phylogenetically close to Chinese and Japanese species and helps to separate an Asian clade from an American clade.

Root-knot nematodes were discovered in severely declining creeping bentgrass putting greens at a golf course in Indian Wells, Riverside County, California. The exhibited disease symptoms included chlorosis, stunted growth, and dieback. Based on morphological examination and measurements of J2 females and males, it was suggested that the causal pathogen was . This identification was confirmed by analysis of the D2-D3 expansion segments of 28S rRNA and gene sequences. The host status of 28 plant species was evaluated in greenhouse trials. All tested monocots, except rye and species, were found to be hosts, while no reproduction occurred on dicots. Temperature-tank experiments helped determine that the life cycle of was completed between 17-35 °C, with a base temperature of 8.3 °C and a required heat sum of 493 degree-days (DD). In greenhouse trials in pasteurized soil and near-ideal growing conditions, did not cause significant growth reduction of creeping bentgrass cv. Penn A-4, even at very high J2 inoculation densities. It is highly probable that other biotic and abiotic factors contributed to the observed putting green damage.

A new species of the genus isolated from the bark of a dead red pine tree was characterized using morphometric data and molecular DNA barcodes. n. sp. was characterized by its medium sized body 2.50 to 2.98 mm long; lip region truncate, angular and offset by a depression; odontostyle 23.5 to 27.0 μm long; basal shield of pharynx present; vulval opening wide and longitudinal, positioned slightly anteriorly (V = 42.5-47.7); several advulval papillae; female tail long and filiform (324.0-435.0 μm long, c' = 10.1-14.2); a clearly visible copulatory hump; spicules 60.0 to 70.5 μm long; 12 to 15 (mostly 12-14) large contiguous ventromedian supplements, and male tail conoid to broadly rounded. The new species was morphologically compared with , and . The phylogenetic relationships among species were reconstructed using 18S- and 28S-rRNA gene sequences. The phylogenies showed well-supported sister relations of n. sp. with and . In addition, the ITS-rRNA gene sequences of n. sp. were supplied, representing the first characterization of the gene for the genus.

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.

Root-knot nematodes (RKNs) are the most destructive nematode species in main pistachio cultivation areas of Iran, and adversely affect crop quality and yield. So far, and have been reported infecting pistachio. In this study, four populations of were found infecting pistachio in Kerman and Khorasan Razavi provinces. The morphology and morphometrics of the recovered populations closely match the data given for other populations of the species. Molecular characterization of the recovered populations was performed by sequencing three genomic and mitochondrial regions, including D2-D3 of LSU rDNA, and mtDNA. The D2-D3 sequences had more than 99% identity with many sequences of tropical species. The sequences had more than 99% identity with sequences of , and . The sequences had 99.81% identity with some sequences of . The D2-D3 and sequences of did not form independent clades in corresponding Bayesian trees, but sequences formed a monophyletic group in corresponding phylogeny. Based on this study, is present in Iran's pistachio gardens, necessitating appropriate management measures.

Cretan dittany ( L.) is an aromatic and medicinal plant, local endemic of the island of Crete, Greece, occurring naturally to high rocky mountain habitats. Due to its commercial interest, cultivation of this plant has been recently expanded. Since natural infestations by spp. in field cultivated plants have not been found, its response to infection by , , , and was investigated in pot experiments. In all experiments, roots of dittany plants exhibited neither galls nor egg masses in contrast to the roots of tomato plants used as controls. Therefore, Cretan dittany appears to be resistant to the five species tested.

n. sp. was recovered and cultured from soils collected under (pencil-bush) in the Namib Desert of Namibia, one of the driest terrestrial habitats on Earth. It is described here based on morphometrics, scanning electron micrographs, light images, line drawings, and molecular data. The new species is distinguished by having a conspicuous posterior deirid, a hook-shaped stegostomal dorsal tooth, and anterior deirids and excretory pore aligned at mid-bulb. It was morphologically compared to eleven well-described species in the genus with which it shared similar labial structure (six distinct rounded lips, and low lip segments separated in pairs), conoid tail, and/or a lateral field with three incisures, including , , , , and . Bayesian phylogenetic analyses using SSU and LSU rDNA each placed n. sp. within clades of species, although the two trees resolved its relationship to previously described species differently. Furthermore, our analyses showed the genus is not monophyletic. In a laboratory experiment, n. sp. survived exposure to 0% relative humidity for 24 h, demonstrating the anhydrobiotic ability of this species that contributes to its survival in the Namib Desert.

California is the primary US producer of processing tomatoes. After decades-long excellent protection against the common tropical spp. , , and (root-knot nematode: RKN) by -resistant tomato cultivars, resistance-breaking RKN populations are spreading throughout the San Joaquin Valley. For some time, nematicidal crop management tools have diminished under CA State regulatory pressure. In recent years, new non-volatile compounds have been developed with novel modes of action. In this project with susceptible processing tomato grown on an -infested site, the efficacy of three fluorinated nematicides was evaluated in 10 field trials from 2011 to 2021. Seven trials included fluensulfone, six included fluazaindolizine, and five included fluopyram. On average, tomato root-galling (0 - 10 scale) at harvest was reduced by 3.2, 2.3, and 2.5 by fluazaindolizine, fluensulfone, and fluopyram, respectively, compared to the untreated control. These reductions in root-galling corresponded with estimated yield gains of approximately 21%, 14%, and 15%, respectively, over the untreated control. The reproduction of RKN during the tomato crop was not affected by the nematicides. The tested compounds have a very low acute mammalian toxicity and are more target-specific than previous generations of nematicides. However, there is considerable concern about the persistence of synthetic per- and polyfluoroalkyl substances (PFAS) in the environment, including pharmaceuticals and pesticides containing fluorine with the C-F3 functional group.

Crop rotation has been a commercial practice for managing the sugarbeet cyst nematode (, SBCN) since the 1950s. Research conducted in southern California established that SBCN populations decline at the rate of 49% to 80% per year, leading to estimates that three- to four-year rotations to nonhost crops would be sufficient to reduce SBCN densities to nondamaging levels. Following grower reports that much longer rotations were needed in central California, trials were conducted to establish the rate of decline of SBCN in the San Joaquin Valley. Ten commercial fields with a history of SBCN infestation were sampled periodically for up to 6.3 years. In each field, 10 circular subplots located 30.5 meters apart (each with a 6-m radius) were established with reference to a permanent landmark. On each sampling date, 12 subsamples from each subplot were taken randomly from the top 0 cm to 30 cm of soil and composited into a single sample. Standard techniques were utilized to extract and count cysts and eggs from soil samples. Average yearly rates of population decline in the sampled fields ranged from 11.4% to 25.8%. This finding has implications for SBCN management in California sugarbeets grown for biofuel, as the lower decline rates indicate that longer nonhost rotation periods than previously anticipated may be necessary.

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. 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; 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 , especially in having similar body length and number of ventromedian supplements but can be differentiated from 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 n. sp. with , and other member species of the group.

, 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. 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. induces hatching but limits reproduction and can be used as an alternative control measure. However, as 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 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.

The ring nematode, , has become recognized as a widespread pest of sweet cherry trees in the Okanagan Valley of British Columbia (BC). Understanding the cumulative impacts of on tree health, interpreting diagnostic sample data, and predicting the impacts of climate change on population densities all depend on knowledge of the temporal dynamics of populations and their linkage with soil temperature and moisture regimes. The objective of this study was to measure population densities of on a monthly basis over five years, in relation to soil temperature and moisture regimes, in a 16-year-old irrigated sweet cherry orchard. We tested the following hypotheses: (i) population densities would start low each spring and increase continuously with soil degree-day heat accumulation during each growing season, and (ii) year-to-year variation in population growth during the growing season would be correlated with year-to-year variation in soil degree-day heat accumulation. The data did not support these hypotheses and indicated that although there were significant differences in population densities among sample dates, there were no regular seasonal cycles of population growth and decline. We suggest that in mature cherry orchards, density-dependent processes mask the influences of annual changes in soil temperature and moisture on population processes. The data indicate that for diagnostic sampling purposes, all seasons would be equally representative of population densities in irrigated orchards in BC. Furthermore, the lack of any strong linkage between soil temperature regimes and within- or across-year population dynamics indicate that modeling efforts based solely on abiotic drivers of temperature and moisture would not likely represent changes in population dynamics of that will actually occur with climate change.

Mexico is the 8 largest producer of tomatoes. is reported in Sinaloa, affecting tomato cultivars with genetic resistance to spp. We aimed to evaluate field applications of fluopyram, fluensulfone, and fluazaindolizine treatments for managing on tomatoes. Experiments were set on raised beds in a shade house. Nematicides were applied via drip irrigation. Under fluopyram treatment, 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 . Yield from the treatments fluopyram, fluazaindolizine plus fluopyram, and fluensulfone plus fluopyram was similar to the control treatment without . 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 in the tomato crop.

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 () and two shrubs , ) to , and . Each plant/nematode treatment was replicated five times, and the experiment was conducted twice. Plants were inoculated with 3,000 eggs of or and 2,500 individuals of two weeks after planting. After three months, the plants were harvested, and the total density of nematodes in soil and roots for and the total density of second-stage juveniles (J2) in soil and eggs on roots for and were determined. The final nematode population (Pf) and reproductive factor (RF = Pf/initial population density) were calculated. For and , all of the ornamental trees and shrubs would be considered as fair to good hosts with RF values > 1. had the highest Pf (5,234 total J2 and eggs/pot) and RF value (28.4) on . For , all of the ornamental trees and shrubs were fair to good hosts, except for . was not a host for with an RF value of almost 0. This is the first report of , and as hosts for , and . This is also the first report of and as hosts for and the non-host status of for .

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 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.

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 . In the southeastern United States, is an economically important pathogen of warm season turfgrass. The density was four individuals/100 cm of soil, and no visual symptoms were observed in the bermudagrass field. Morphological features and morphometrics of males and females were consistent with 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 populations including those from Alabama, Delaware, Florida, Indiana, Mississippi, South Carolina, and Texas. To our knowledge, this is the first report of in Maryland.

Sweetpotato is an important crop whose roots are consumed by people worldwide. 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 was assessed both and in growth cabinet experiments. After 48 hours of exposure, fluopyram and cyclobutrifluram had a greater negative effect on the motility of second-stage juveniles (J2s) compared to fluensulfone and hymexazol, with respective median effective concentration (EC) values of 0.204, 0.423, 22.335 and 216.622 mg L. When eggs were incubated for 72 hours at the highest concentration of each nematicides, the inhibitory hatching effect of cyclobutrifluram (2.5 mg L), fluopyram (1.25 mg L) and fluensulfone (80 mg L) surpassed 85%, whereas hymexazol (640 mg L) 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 in sweetpotato, and this is the first report on the nematicidal activity of cyclobutrifluram and hymexazol against .

The hop cyst nematode, , is the most common plant-parasitic nematode associated with hop worldwide. This study reports the draft genome of 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 and other cyst nematodes.

, the pale cyst nematode (PCN), is a quarantine pest of potato posing a serious threat to the Idaho potato industry. only hatches in the presence of a hatching stimulus produced by a host plant or closely related species. In the absence of this hatching stimulus, can remain viable in the soil for decades. A trap crop stimulates hatch of but is a nonhost, which means the nematode cannot develop or reproduce. This study evaluated the trap crop potential of several solanaceous species by determining host status and hatching effect of each species. The species under investigation included , , , , and . All species were determined to be nonhosts of . The most promising trap crop candidates with a hatching stimulatory effect comparable to potato were and Further research is needed to assess whether these species could be effective trap crops under Idaho field conditions.