rss_2.0Sciendo RSS Feed for Journal of Nematologyhttps://sciendo.com/journal/JOFNEMhttps://www.sciendo.comhttps://sciendo-parsed.s3.eu-central-1.amazonaws.com/64722261215d2f6c89dbcfbd/cover-image.jpghttps://sciendo.com/journal/JOFNEM140216https://sciendo.com/article/10.2478/jofnem-2023-0035<abstract> <title style='display:none'>Abstract</title> <p><italic>Rotylenchulus reniformis</italic> (reniform nematode, RN) is an important pathogen in cotton production. Cultural practices such as crop rotation and biofumigation—management of soil pathogens by biocidal compounds from crop residues—may help manage RN. The objective of this study was to evaluate the efficacy of winter crops for RN management through combinations of rotation and crop residue incorporation in a cotton greenhouse experiment. A total of 10 treatments were evaluated in soil inoculated with RN: three winter crops (carinata, oat, or hairy vetch) grown in rotation with no shoot organic matter (OM) incorporated (1–3), fresh shoot OM incorporated (4–6), or dry shoot OM incorporated (7–9), and a fallow control (10). Roots were re-incorporated in all treatments except fallow. Subsequently, cotton was grown. Oat and fallow were better rotation crops to lower soil RN abundances at winter crop termination than hairy vetch and carinata. After the OM incorporation treatments and cotton growth, oat was generally more effective at managing RN in cotton than carinata or hairy vetch. Within each crop, incorporation treatment generally did not affect RN management. Cotton growth was not consistently affected by the treatments.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00352023-09-13T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0037<abstract> <title style='display:none'>Abstract</title> <p>While the nematicidal effectiveness of mulching against root-knot nematodes (<italic>Meloidogyne</italic> spp.) is calculated within organic crop protection, underlying mechanisms are not yet fully explored. Laboratory experiments were set up to determine whether mulch-derived substances cause mortality directly, or repel <italic>Meloidogyne</italic> juveniles from crop rhizosphere. Mortality and area choice tests were conducted with mulch-derived extracts, supported by the measurements on tannic acid content and the pH values of extracts as supplementary examinations. In our study, leaf litter and straw extracts were generally found lethal to the juveniles, which is in line with the results from area preference tests. However, compost extract had no effect on <italic>Meloidogyne incognita</italic> juveniles. Tannic acid content showed positive correlation with mortality only in the case of straw and sycamore leaf litter extracts. Tannic acid and pH weakly correlated with repellent effect of the applied extracts generally. Our results have inspired further experiments to explore nematicidal components of leaf litters, contributing to the development of a new approach in crop protection based on the repellent effect of these materials.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00372023-09-01T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0036<abstract> <title style='display:none'>Abstract</title> <p><italic>Globodera pallida</italic>, the pale cyst nematode (PCN), is a quarantine pest of potato posing a serious threat to the Idaho potato industry. <italic>Globodera pallida</italic> 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, <italic>G. pallida</italic> can remain viable in the soil for decades. A trap crop stimulates hatch of <italic>G. pallida</italic> 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 <italic>G. pallida</italic> host status and hatching effect of each species. The species under investigation included <italic>Solanum aethiopicum</italic>, <italic>S. macrocarpon</italic>, <italic>S. quitoense</italic>, <italic>S. retroflexum</italic>, and <italic>S. douglasii</italic>. All species were determined to be nonhosts of <italic>G. pallida</italic>. The most promising trap crop candidates with a hatching stimulatory effect comparable to potato were <italic>S. quitoense</italic> and <italic>S. retroflexum.</italic> Further research is needed to assess whether these species could be effective <italic>G. pallida</italic> trap crops under Idaho field conditions.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00362023-09-01T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0030<abstract> <title style='display:none'>Abstract</title> <p>We previously reported soybean fields double-cropped with winter wheat having reduced soybean cyst nematode (SCN) (<italic>Heterodera glycines</italic>) counts compared to fallow. A follow-up metagenomics study identified several fungal and bacterial taxa enriched in wheat fields, and some were reported to parasitize SCN. Knowing that phytocompounds with potential nematicidal activity are released via wheat roots and stubble, we implemented a dichloromethane-based extraction method and a gas chromatography-mass spectrometry (GCMS) system to investigate soil chemical profiles of samples collected from these fields and review the potential nematicidal activity of compounds with higher concentration in double cropping fields. 51 compounds were detected during the GCMS analysis, eight with unknown identification. Several compounds, including multiple fatty acids, had larger relative peak areas when double-cropped, compared to fallow samples. This study, along with our previously published one, provided a better understanding of the mechanisms that govern the effect of wheat on SCN populations. Rather than driven by a single mechanism, the suppression of SCN in soybean fields double-cropped with winter wheat was potentially linked to enriched microbial communities, increased populations of beneficial organisms, and higher concentrations of chemicals with potential nematicidal activity. To our knowledge, this is the first study using GCMS to characterize soil chemical profiles in soybean fields double-cropped with winter wheat regarding the suppression of SCN populations.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00302023-08-29T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0033<abstract> <title style='display:none'>Abstract</title> <p>Chitosan is the second most abundant bio-polymer available in the world, second only to cellulose. It is found in crustaceous shells, e.g., those of crabs, shrimps, prawns, and fungi, as well as insect exoskeletons. The use of nanoformulations for the management of pests and diseases is receiving increased interest with the advancement of nanotechnology. Here, chitosan nanospheres were obtained from chitosan using the ionic gelation technique. The nanoformulations obtained were characterized using a particle size analyzer, Fourier transform infrared spectroscopy, and a transmission electron microscope. The efficacy of chitosan nanospheres in suppressing the root-knot nematode <italic>Meloidogyne incognita</italic> was studied. The particle size of nanospheres formulated for this study was 380.2 nm, with a polydispersity index (PI) of 0.4 and Zeta potential of 45.7 or 50.9 mV at pH 5.2. The chitosan nanospheres were spherical and the particles did not agglomerate. FTIR spectra of the chitosan nanospheres peaked at 3334 cm⁻¹, thereby indicating the stretching of the OH and NH group. In In-vitro studies, chitosan nanospheres showed significant nematicidal activity against <italic>M. incognita</italic>. Under pot culture conditions, chitosan nanospheres (1%- active compound chitosan) at 2ml/plant decreased the nematode population in roots or soil. Compared to the control, the number of galls was reduced by 83.68%, the number of egg masses by 83.85%, the number of adult females by 66.56%, and the number of second-stage juveniles by 73.20%. In a field experiment, application of chitosan nanospheres (1%) was followed by a 18.75% increase in fruit yield compared to the non-treated control.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00332023-08-24T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0034<abstract> <title style='display:none'>Abstract</title> <p>Strawberry (<italic>Fragaria</italic> × <italic>ananassa</italic>) is native to temperate regions. However, it has been produced in tropical areas, as a seasonal crop including in Florida, USA during the winter months. In March 2022, root galls resembling those induced by root-knot nematodes (<italic>Meloidogyne</italic> spp.) were observed in declining strawberry plants ‘Winterstar^TM FL 05-107’ growing in an organic-certified research site in Hillsborough County, Florida, USA. To our knowledge, <italic>M. hapla</italic> is the only root-knot species reported to infect strawberry in Florida. Preliminary molecular analyses, including newly synthesized DNA sequences (TW81/AB28 = OQ469833 - OQ469836; D2A/D3B= OQ473043 - OQ473047) using extracted nematode females from the strawberry roots, initially identified the RKN as <italic>M. javanica</italic>. Nematode species confirmation was further performed using the morphology of the female perineal patterns and isozyme analysis, mainly esterase (EST) and malate dehydrogenase (MDH), DNA sequencing, (NAD5-F/NAD5-R) and the SCAR primer set (Fjav/Rjav), species-specific for <italic>M. javanica</italic>. Isozyme analyses, EST= J3, which is specific for <italic>M. javanica</italic> and MDH=N1, as well as the morphology of female perineal patterns, agreed with data previously reported for <italic>M. javanica</italic>. A pathogenicity test on strawberry ‘Winterstar^TM FL 05-107’ transplants was performed using 10,000 eggs of the original <italic>M. javanica</italic> population, which induced galls on strawberry plants (Gall index, GI = 4.1) with egg masses clearly visible outside of the roots, producing an average of 1,344 eggs/gram of fresh root and 9,201 ± 4,206 eggs/root system. No galls or egg masses were observed on non-inoculated plants. Tomato ‘HM 1823’ was used as a control for the viability of the inoculum and showed numerous galls and egg masses (GI=5.0;).</p> <p>The newly obtained DNA sequences using NAD5-F/NAD5-R (OQ474970 – OQ474972) were compared with other sequences available in the GenBank and were shown to be 100% identical to five <italic>M. javanica</italic> populations from Polk County, Florida, USA (OM418745 – OM418749) and the complete mitochondrion genome of <italic>M. javanica</italic> (NC026556). To our knowledge, this is the first report of <italic>M. javanica</italic> infecting strawberry in the United States.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00342023-08-24T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0032<abstract> <title style='display:none'>Abstract</title> <p>Most commercial flue-cured tobacco cultivars contain the <italic>Rk1</italic> resistance gene, which provides resistance to races 1 and 3 of <italic>Meloidogyne incognita</italic> and race 1 of <italic>M. arenaria</italic>. A number of cultivars now possess a second root-knot resistance gene, <italic>Rk2</italic>. High soil temperatures have been associated with a breakdown of root-knot resistance genes in a number of crops. Three greenhouse trials were performed from 2014 to 2015 investigate the effect of high soil temperature on the efficacy of <italic>Rk1</italic> and/or <italic>Rk2</italic> genes in reducing parasitism by a population of <italic>M. incognita</italic> race 3. Trials were arranged in randomized complete block design in open-top growth chambers set at 25°, 30°, and 35°C. Plants were inoculated with 3,000 eggs and data were collected 35 days post-inoculation. Galling, numbers of egg masses and eggs, and reproductive index were compared across cultivar entries. Nematode reproduction was reduced at 25°C and 30°C on entries possessing <italic>Rk1</italic> and <italic>Rk1Rk2</italic> compared to the susceptible entry and the entry possessing only <italic>Rk2</italic>. However, there were often no significant differences in reproduction at 35°C between entries with <italic>Rk1</italic> and/or <italic>Rk2</italic> compared to the susceptible control, indicating an increase of root-knot nematode parasitism on resistant entries at higher temperatures. Although seasonal differences in nematode reproduction were observed among experiments, relative differences among tobacco genotypes remained generally consistent.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00322023-08-01T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0026<abstract> <title style='display:none'>Abstract</title> <p>Soybean Cyst Nematode (SCN), <italic>Heterodera glycines</italic> Ichinohe, is the most important pathogen of soybean in the Mid-Atlantic region. In recent decades, a decline in the effectiveness of genetic resistance has been observed and additional management approaches are needed. Seed treatments are of rising interest, but no local data on product response exists for the region. In 2020–2021, two experiments were conducted to observe the effects of chemical and biological seed treatment options. In one experiment, chemical seed treatments pydiflumetofen (Saltro®) and fluopyram (ILEVO®) were screened against nontreated plain seed for SCN suppression. In a second experiment, pydiflumetofen, fluopyram and four biological nematode-protectant seed treatments with a standard base insecticide and fungicide treatment were compared to nontreated plain seed and seed with only the standard base treatment to test product efficacy against SCN. Seed treatments increased the percent emergence over plain seed. Nematode reproductive factors and female counts from roots were collected, but did not statistically differ between seed treatments or plain seed. Yield differences were observed in one of the five trials, where pydiflumetofen + base seed treatment yielded the highest (<italic>p</italic> &lt; 0.001) at 3813.1 kg/ha. Response from seed treatments varied, with no specific seed treatment consistently reducing SCN populations or increasing yield across trials. Seed treatments may have potential as an element of an integrated management approach for SCN.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00262023-08-01T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0029<abstract> <title style='display:none'>Abstract</title> <p>Three entomopathogenic nematode populations were isolated from agricultural fields in the Anantnag district of Jammu and Kashmir (India). Sequences of multiple gene regions and phenotypic features show that they are conspecific and represent a novel species. Molecular and morphological features provided evidence for placing the new species into the “<italic>Kushidai</italic>” clade. Within this clade, analysis of sequence data of the internal transcribed spacer (ITS) gene, the D2D3 region of the 28S rRNA gene, the mitochondrial cytochrome oxidase I (<italic>mtCOI</italic>) gene, and the mitochondrial 12S (<italic>mt12S</italic>) gene depicted the novel species as a distinctive entity closely related to <italic>Steinernema akhursti</italic>, <italic>S. kushidai</italic>, and <italic>S. populi</italic>. Phylogenetic analyses also show that the new species is a sister species to <italic>S. akhursti</italic>, and these two species are closely related to <italic>S. kushidai</italic> and <italic>S. populi</italic>. Additionally, the new species does not mate or produce fertile progeny with any of the closely related species, reinforcing its uniqueness from a biological species concept standpoint. The new species is further characterized by the third-stage infective juveniles with almost straight bodies (0.7–0.8 mm length), poorly developed stoma and pharynx, and conoid-elongate tail (49–66 µm) with hyaline posterior part. Adult females are characterized by short and conoid tails bearing a short mucron in the first generation and long conoid tails with thin mucron in the second generation. Adult males have ventrally curved spicules in both generations. Moreover, the first-generation male has rounded manubrium, fusiform gubernaculum, conoid and slightly ventrally curved tails with minute mucron, and the second generation has rhomboid manubrium anteriorly ventrad bent, and tails with long and robust mucron. The morphological, morphometrical, molecular, and phylogenetic analyses support the new species status of this nematode, which is hereby described as <italic>Steinernema anantnagense</italic> n. sp. The bacterial symbiont associated with <italic>S. anantnagense</italic> n. sp. represents a novel species, closely related to <italic>Xenorhabdus japonica</italic>. These findings shed light on the diversity of entomopathogenic nematodes and their symbiotic bacteria, providing valuable information for future studies in this field.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00292023-07-13T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0018<abstract> <title style='display:none'>Abstract</title> <p>The subtropical climate of Florida allows for a wide range of crops to be grown. With the classification of hemp (<italic>Cannabis sativa</italic> L., &lt;0.3% delta-9-tetrahydrocannabinol) as an agricultural commodity, hemp has become a potential alternative crop in Florida. Hemp cultivars of different geographies (Europe, China, and North America), and uses (fiber, oil and CBD), were evaluated in three field experiments. The field experiments evaluated a total of 26 cultivars and were conducted for two consecutive seasons at three different locations (soil types) in North (sandy loam), Central (fine sand), and South Florida (gravelly loam). Nematode soil populations were measured at the end of each season. A diverse population of plant-parasitic nematodes was found, with reniform nematodes (RN, <italic>Rotylenchulus reniformis</italic>) the dominant species in North and South Florida (up to 27.5 nematodes/cc soil), and RKN (<italic>Meloidogne javanica</italic>) the main species in central Florida (up to 4.7 nematodes/cc soil). Other nematodes that were commonly found in south Florida (and to a lesser extent north Florida) were spiral (<italic>Helicotylenchus</italic> spp.), stunt (<italic>Tylenchorhynchus</italic> spp.) and ring nematodes (Criconemoids), while in central Florida, stubby root (<italic>Nanidorus minor</italic>) and sting nematodes (<italic>Belonolaimus longicaduatus</italic>) were found. No significant difference among hemp cultivars was noted at any of the locations. RKN were found in all three regions and soils, while RN were only found in North and South Florida. This is the first report on plant-parasitic nematodes associated with hemp in Florida fields. Natural nematode populations varied greatly, depending on where in Florida hemp was grown. Growers who wish to include hemp in their crop rotation need to be aware of potential pest pressure from nematodes. More research is needed to determine to what extent nematodes, especially RKN and RN, can reduce hemp growth and yield.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00182023-07-06T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0028<abstract> <title style='display:none'>Abstract</title> <p><italic>Belonolaimus longicaudatus</italic> (sting nematode) is an important pest in Florida potato production and is managed primarily by fumigation using 1,3-dichloropropene (1,3-D). Other effective nematicides are needed for more flexibility in managing this pest. The objective of this study was to evaluate fluensulfone, metam potassium, and mixtures of the two products, relative to 1,3-D and untreated control, for efficacy at managing sting nematode, and for non-target effects on free-living nematodes in potato. To test this objective, a small-plot field experiment was conducted in northeast Florida in 2020 and repeated in 2021. Metam potassium fumigation (390 kg a.i./treated ha)—with or without fluensulfone—managed sting nematode soil abundances but was phytotoxic to potato. Strategies that mitigate metam potassium phytotoxicity, such as reduced application rates, are needed before efficacy of metam potassium in this system can be determined. As a preplant soil spray, fluensulfone alone (403 g a.i./treated ha) did not manage sting nematode abundances and had an inconsistent effect on yield. Fumigation with 1,3-D (88.3 kg a.i./treated ha) was the only treatment that consistently managed sting nematode and increased potato yield. Nematicides did not consistently affect free-living nematodes.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00282023-07-06T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0021<abstract> <title style='display:none'>Abstract</title> <p><italic>Meloidogyne enterolobii</italic> [the guava root-knot nematode (RKN)] is an emerging plant-parasitic nematode that poses a threat to Upland cotton (<italic>Gossypium hirsutum</italic>) production in the southeastern United States. Like other RKN spp., <italic>M. enterolobii</italic> has a wide host range and proven ability to overcome resistance sources that have helped protect crops from other <italic>Meloidogyne</italic> spp., including the southern RKN (<italic>Meloidogyne incognita</italic>). In this study we evaluated the virulence of two North Carolina <italic>M. enterolobii</italic> isolates on Upland cotton germplasm lines having resistance quantitative trait loci (QTL) to RKN (M240 RNR, MRk-Rn-1) and/or reniform nematode (<italic>Rotylenchulus reniformis</italic>) (M713 Ren1, MRk-Rn-1) in comparison to their susceptible recurrent parents (DPL61, SG747). Multiple assays using eggs or J2 as inoculum demonstrated that both isolates reproduced equally well on all germplasm lines, producing reproductive factor (RF) values ≥ 6 on the otherwise nematode-resistant lines. Measurements of seedling growth in control and inoculated containers suggested that existing nematode-resistance QTL may offer a level of tolerance to <italic>M. enterolobii</italic> infection that should be further explored in greenhouse and field environments. <italic>Meloidogyne enterolobii</italic> infection of SG747 and MRk-Rn-1 showed nearly identical stages of symptom and nematode development over a time-course of 24 days. These data demonstrate that existing RKN and RN resistance QTL available in elite cotton varieties to producers are most likely insufficient in preventing yield loss due to <italic>M. enterolobii</italic> and that future research should focus on (i) understanding the <italic>M. enterolobii</italic>–cotton interaction at the molecular level, and (ii) screening novel germplasm collections to identify resistance loci.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00212023-06-23T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0015<abstract> <title style='display:none'>Abstract</title> <p>Plant-parasitic nematodes (PPNs) can cause substantial economic yield losses to many agronomic crops in the United States. A regional-scale survey was completed across 20 counties to determine PPNs prevalence in Michigan corn and how factors such as soil type, tillage, irrigation, and cropping systems influence their distribution. Ten different major genera of PPNs were identified in Michigan corn fields: <italic>Longidorus</italic> (needle), <italic>Helicotylenchus</italic> (spiral), <italic>Pratylenchus</italic> (lesion), <italic>Meloidogyne</italic> (root-knot), <italic>Heterodera</italic> (cyst), <italic>Hoplolaimus</italic> (lance), <italic>Tylenchorhynchus</italic> or <italic>Merlinius</italic> (stunt), <italic>Paratylenchus</italic> (pin), <italic>Criconemella</italic> (ring), and <italic>Xiphinema</italic> (dagger). No significant differences among different categories of tillage for lesion, stunt, or needle nematode prevalence was detected. Lesion nematodes were most prevalent in muck soil, while stunt nematode prevalence was significantly affected by the soil type. Needle nematodes were least abundant in irrigated soils and in contrast, stunt nematodes were higher in non-irrigated soils. Spiral nematodes were the most common PPNs in Michigan corn in all cropping systems. These findings will be helpful in planning future nematode studies in Michigan and in developing and evaluating corn nematode management strategies.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00152023-05-02T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0027<abstract> <title style='display:none'>Abstract</title> <p>Chickpea (<italic>Cicer arietinum</italic> L.) is classed among the most important leguminous crops of high economic value in Ethiopia. Two plant-parasitic nematode species, <italic>Pratylenchus delattrei</italic> and <italic>Quinisulcius capitatus</italic>, were recovered from chickpea-growing areas in Ethiopia and characterized using molecular and morphological data, including the first scanning electron microscopy data for <italic>P. delattrei</italic>. New sequences of D2-D3 of 28S, ITS rDNA and mtDNA <italic>COI</italic> genes have been obtained from these species, providing the first <italic>COI</italic> sequences for <italic>P. delattrei</italic> and <italic>Q. capitatus,</italic> with both species being found for the first time on chickpea in Ethiopia. Furthermore, <italic>Pratylenchus delattrei</italic> was recovered in Ethiopia for the first time. The information obtained about these nematodes will be crucial to developing effective nematode management plans for future chickpea production.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00272023-06-11T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0024<abstract> <title style='display:none'>Abstract</title> <p>A three-year rotation of cotton (<italic>Gossypium hirsutum</italic>) cultivars either resistant (R) or susceptible (S) to <italic>Rotylenchulus reniformis</italic> and fallow (F) was examined for effect on cotton yield and nematode density. In year 1, 2, and 3, the resistant cultivar (DP 2143NR B3XF) yielded 78, 77, and 113% higher than the susceptible cultivar (DP 2044 B3XF). Fallow in year 1 followed by S in year 2 (F1S2) improved yield in year 2 by 24% compared with S1S2, but not as much as R1S2 (41% yield increase over S1S2). One year of fallow followed by R (F1R2) had lower yield in year 2 (11% reduction) than R1R2. The highest yield after three years of these rotations occurred with R1R2R3, followed by R1S2R3 (17% less yield) and F1F2S3 (35% less yield). <italic>Rotylenchulus reniformis</italic> density in soil averaged 57, 65, and 70% lower (year 1, 2, 3, respectively) in R1R2R3 compared with S1S2S3. In years 1 and 2, LOG₁₀ transformed nematode density (LREN) was lower in F1, and F1F2, than for all other combinations. In year 3, the lowest LREN were associated with R1R2R3, F1S2F3, and F1F2S3. The highest LREN were associated with F1R2S3, F1S2S3, S1S2S3, R1R2S3, and R1S2S3. The combination of higher yield and lower nematode density will be a strong incentive for producers to use the <italic>R. reniformis</italic> resistant cultivars continuously.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00242023-06-06T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0020<abstract> <title style='display:none'>Abstract</title> <p>Root-knot nematodes (RKN) cause considerable economic losses to kiwifruit production annually. Screening of resistant cultivars has been one of the long-standing methods to manage root-knot nematodes. Here, the reaction of the four most common commercial cultivars of kiwifruit, namely, <italic>Actinidia chinensis</italic> var. <italic>deliciosa</italic> cv. Hayward, <italic>A. chinensis</italic> var. <italic>deliciosa</italic> cv. Abbott, <italic>A. chinensis</italic> var. <italic>deliciosa</italic> cv. Bruno, and <italic>A. chinensis</italic> var. <italic>chinensis</italic> cv. Haegeum (commonly known as ‘Golden’ kiwifruit) to infection by the RKN, <italic>Meloidogyne incognita</italic>, was evaluated. Among examined cultivars ‘Golden’ was the most susceptible, having on average 52.8 galls, 56.1 egg masses per gram of root, and 642 J2 population per 200 gram of soil. ‘Bruno’ showed the highest resistance, with 3.3 galls, 4.1 egg masses per gram of root, and 79 J2 in 200 g of soil. Then, two potential biological control agents, namely <italic>Priestia megaterium</italic> 31.en and <italic>Agrobacterium tumefaciens</italic> 19.en were used on ‘Hayward’ seedlings against <italic>M. incognita</italic> and showed a significant reduction in the number of galls and egg masses on roots, juvenile population in the soil, and increased the growth parameters of the plants compared to non-treated seedlings. We demonstrated that integrated management using resistant cultivars and biological control can provide a safe and economic method to control RKN, and these resistant cultivars can be used in breeding programs.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00202023-06-05T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0016<abstract> <title style='display:none'>Abstract</title> <p>In 2019–2022, declining symptoms were observed in two commercial strawberry farms in Hillsborough County, Florida. The fields in the two farms consisted of raised beds covered by plastic mulch. Both were fumigated with a mixture of 1,3-dichloropropene (40%) + chloropicrin (60%) before planting. Samples collected from large patches with declining plants were infested with stubby-root nematodes. No sting and root-knot nematode species were detected. The results of morphological and molecular analyses indicated that the stubby-root nematode populations were representative of the species <italic>Nanidorus minor</italic>. The two cultivars ‘Florida Brilliance’ and ‘Florida Sensation’ in the two fields included plants with stubby root symptoms showing a reduction in the size of the root system and arrested growth and elongation of the feeder roots on the first strawberry crop. The nematode population densities in the two fields increased at the end of strawberry season and averaged 66 and 96 specimens in 200 cm³ soil. In one of the fields, a second strawberry crop was established as in the previous year using the same practices (fumigation and raised beds covered with plastic). However, in this field the population of <italic>N. minor</italic> declined and did not reach damaging levels at the end of the season on the second strawberry crop. The factors causing the decline of the nematode population were not elucidated. This is the first report of a direct damaging effect of <italic>N. minor</italic> to strawberry.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00162023-06-05T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0025<abstract> <title style='display:none'>Abstract</title> <p><italic>Meloidogyne enterolobii</italic> is a highly aggressive quarantine pathogen which threatens the multibillion-dollar tobacco industry and is not manageable with the currently available management methods in tobacco. There is currently no known host plant resistance in tobacco and previous studies have shown that the lower level of the currently recommended rate of non-fumigant nematicides does not provide satisfactory management of <italic>M. enterolobii</italic>. The current study was conducted with the hypothesis that <italic>M. enterolobii</italic> can be better managed using a single soil application of the maximum allowed rate of non-fumigant nematicides. Treatments involved three non-fumigant chemical nematicides (oxamyl, fluopyram, and fluensulfone), a biological nematicide derived from Burkholderia, and a non-treated control. Fluensulfone significantly suppressed the nematode reproduction relative to the control, the suppression being 71% for eggs and 86% for the second stage juveniles (J2). Fluopyram also suppressed nematode reproduction, although this was statistically insignificant, with the suppression being 26% and 37% for eggs and J2, respectively. Oxamyl significantly suppressed J2 (80%), but not eggs (50%) in relation to the control. The most significant reduction of disease severity was achieved by the application of fluensulfone (64%), followed by oxamyl (54%) and fluopyram (48%). Except for fluensulfone, which significantly reduced the root biomass, none of the nematicides significantly impacted root and shoot biomass. The biological nematicide did not significantly affect nematode reproduction, pathogenicity, or disease severity. The results from the current study suggest that while the non-fumigant nematicides provided a good level of the nematode suppression, more research is needed to improve the efficacy of non-fumigant nematicides through employing better application methods or finding better chemistries.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00252023-06-05T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0022<abstract> <title style='display:none'>Abstract</title> <p>A new species of the genus <italic>Talanema</italic>, recovered from the northwest of Iran, was described based on morphological, morphometric, and molecular data. <italic>Talanema</italic> eshtiaghii sp. n. was characterized by its 1.45–1.68 mm long body, lip region offset by constriction and 13–15 μm wide, odontostyle 15–18 μm long, double guiding ring, neck 312–362 μm long, pharyngeal expansion occupying 41–43% of the total neck length, uterus tripartite, and 111–189 μm long or 2.1–3.2 body diameters, vulva transverse (V = 55–58), tail similar in both sexes, conical with a dorsal concavity (30–44 μm, c = 33–56, c’ = 1.0–1.6), spicules 49–56 μm long, and 14–18 shortly spaced ventromedian supplements in front of the level of the anterior end of spicules, with distinct hiatus. It was compared to four closely similar species, with emphasis on the most relevant traits to distinguish them. Molecular phylogenetic studies using partial sequence of the 28S rDNA (D2–D3 segment) revealed that the new species forms a clade with other currently sequenced representatives of <italic>Talanema</italic>, tentatively supporting the monophyly of this genus.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00222023-06-05T00:00:00.000+00:00https://sciendo.com/article/10.2478/jofnem-2023-0023<abstract> <title style='display:none'>Abstract</title> <p>Tomato plants are susceptible to significant yield losses when infested by the northern root-knot nematode, <italic>Meloidogyne hapla.</italic> While there are many options for conventional chemical management, few of these options offer effective control for organic growers or those who seek to adopt more environmentally considerate strategies. In this study, we showed that a new, biologically based product (referred to as “MN21.2”) has potential for controlling populations of the northern root-knot nematode, <italic>Meloidogyne hapla</italic>, as a pest of susceptible tomato (cv. Rutgers) in a greenhouse trial. This is significant because if this product’s efficacy is supported under field conditions, it may provide organic tomato growers with a valuable tool for fighting the plant-parasitic nematode pest, <italic>M. hapla.</italic></p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/jofnem-2023-00232023-05-26T00:00:00.000+00:00en-us-1