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Root knot nematode (RKN), Meloidogyne incognita, is considered a major soil-borne pathogen that can cause severe yield losses for vegetables and diverse crops. Usually, reducing of M. incognita damage is mainly relies on the application of nematicides and good agricultural practices. However, the use of synthetic nematicides is restricted due to concerns about their impact on the environment and human health. As a result, the use of alternative strategies is becoming necessary to combat RKN resistance. This study evaluates the antagonistic impact of the root mutualistic fungus Piriformospora indica on M. incognita. It also assesses its influence on the nutritional status, photo-synthesis, antioxidant enzyme activity, endogenous abscisic acid (ABA) levels, and selected ABA related-responsive genes in cucumber plants. Roots of cucumber seedlings were inoculated with P. indica and the second-stage juveniles (1000 J2 per plant). The results demonstrated that P. indica significantly reduced M. incognita invasion in roots, resulting in a 24% reduction in root galling and 42.6% decline in final population. Inoculating plants with both P. indica and RKN increased performance of root fresh and dry weight, as well as improved photochemical efficiency of PSII (Fv/Fm), photosystem II efficiency (PSII), catalase (CAT), peroxidase (POD), and superoxide dis-mutase (SOD). Furthermore, P. indica colonization, either alone or in combination with M. incognita, significantly improved number of fruits per plant, average fruit weight, the plant's marketable yield, and leaf nutrient content (N, P, K and Mg), Moreover, there was an increase in IAA content combined with a decrease in ABA content in roots of dual inoculation plants, if compared to M. incognita infested plants. The highest ABA content was recorded in the root of RKN-cucumber plants. The decline in ABA content due to P. indica treatment was consistent with the modulation of ABA pathway genes, specifically PP2C, PYL1, RK2,1, and RK2,2. The mixed of P. indica and M. incognita led to a decrease in the expression of PP2C, PLY1, RK2,1, and RK2,2 in comparison to the control group. These results indicate that P. indica application could help reduce the negative effects of RKN on important crops. [ABSTRACT FROM AUTHOR]

The use of arbuscular mycorrhizal fungi (AMF) offers promising benefits to agriculture in the Amazon regions, where soils are characteristically acidic and nutrient-poor. The purpose of this research was to investigate the potential effects of two recently described species of AMF (Nanoglomus plukenetiae and Rhizoglomus variabile) native to the Peruvian Amazon for improving the plant growth of Plukenetia volubilis (inka nut or sacha inchi) and protecting the roots against soil pathogens. Two assays were simultaneously conducted under greenhouse conditions in Peru. The first focused on evaluating the biofertilizer effect of AMF inoculation, while the second examined the bioprotective effect against the root knot nematode, Meloidogyne incognita. Overall, the results showed that AMF inoculation of P. volubilis seedlings positively improved their development, particularly their biomass, height, and the leaf nutrient contents. When seedlings were exposed to M. incognita, plant growth was also noticeably higher for AMF-inoculated plants than those without AMF inoculation. Nematode reproduction was significantly suppressed by the presence of AMF, in particular R. variabile, and especially when inoculated prior to nematode exposure. The dual AMF inoculation did not necessarily lead to improved crop growth but notably improved P and K leaf contents. The findings provide strong justification for the development of products based on AMF as agro-inputs to catalyze nutrient use and uptake and protect crops against pests and diseases, especially those that are locally adapted to local crops and cropping conditions. [ABSTRACT FROM AUTHOR]

In many agroecosystems, soil suppressiveness to root knot nematodes (RKN) is of great interest in defining the biological agents controlling population density, especially with growing concerns about the environmental and human health impacts of chemicals. In this study, we evaluated the suppressiveness to Meloidogyne spp. in two land use soils: a protected argan soil from the Souss Massa National Park (SMNP), Morocco, and a conventional soil from an adjacent non-protected area. Using next-generation sequencing (NGS) technology, we characterized the fungal and bacterial communities in these soils for the first time. Nematodes belonging to different trophic guilds were also analyzed to further understand ecological factors that enable suppressive organisms to function and persist in the soil. The experiment was conducted in a greenhouse with tomato plants grown in untreated and autoclaved soils, each inoculated with 800 Meloidogyne infective juveniles (J2). We found that omnivore-predator nematode abundance, structure, and maturity indices were higher in the protected soil indicating the presence of a well-structured soil food web and a stable ecosystem. After sixty-seven days, RKN population density and gall index were reduced by 79.6 % and 81.5 % in the protected soil, respectively. 50 % autoclaved protected soil was also suppressive, but not 75 % and totally autoclaved soil. In contrast, conventional soil amplified the RKN population by 1319 %. More than 6770 bacterial and 558 fungal taxa were detected in this study, with Firmicutes, Actinobacteria, Mortierellales, Orbiliales, Agaricales, Diversisporales, and Pleosporales being consistently associated with RKN suppression. We found that fungal diversity was higher in SMNP-protected soil. In conclusion, soil protection enhances soil ecosystem resilience and that protected argan soils can serve as a valuable source of biological agents for the sustainable management of phytoparasitic nematodes.

Gene based molecular screening for disease resistance has become a prominent and widely adopted approach in contemporary tomato breeding programs, both in the public and private sectors. The effectiveness of disease-resistant molecular screening relies on the selection of suitable markers that span the entire genomic region for accurate identification of resistant alleles. In this study, various co-dominant and dominant Sequence Characterized Amplified Region (SCAR) markers were employed to screen for resistance genes associated with Tomato yellow leaf curl virus (TyLCV) Ty-1, Ty-2, Ty-3, Fusarium wilt (race-2) I-2, and Root-knot Nematode ((Meloidogyne incognita) Mi-1. The selected markers exhibited high robustness in distinguishing between resistant and susceptible lines. Co-dominant SCAR markers M2 (Ty-1 gene) and TG0302 (Ty-2 gene) efficiently identify homozygous or heterozygous alleles in Tomato yellow leaf curl virus (TyLCV) screening. The P6-25 marker for Ty-3 gene discerns Ty-3, Ty-3a, and Ty-3b alleles, enhancing allele specificity. In Fusarium wilt I-2 gene screening, I-2/5 ensures accurate identification, while in Root-knot Nematode Mi-1 gene screening, co-dominant marker Mi-23 reliably identify and distinguishes homozygous or heterozygous resistant lines without false positives for I-2 and Mi-1 genes. This streamlined marker assisted approach optimizes disease resistance screening in tomato breeding, providing valuable insights for disease resistant cultivar development.

Rice (Oryza sativa) is a highly significant cereal crop on a global scale. Crop plants usually respond to the biotic challenges with altered metabolic composition and physiological perturbations. We have deciphered altered metabolite composition, modulated metabolic pathways and identified metabolite biomarkers in M. graminicola-challenged susceptible rice variety HUR-917 using NMR (Nuclear magnetic resonance) mass spectrophotometry-based metabolomics. In this study, we conducted a comprehensive analysis of the metabolome of susceptible rice plants challenged with the pathogen M. graminicola to unravel complex metabolic changes, identify key biosynthetic pathways, and pinpoint metabolite biomarkers. Through statistical analysis, we identified 100 significant metabolites, with 48 upregulated and 52 downregulated metabolites at a fold change threshold of ≥ 2.0. Multivariate analyses, including Partial Least Squares Discriminant Analysis (PLS-DA) and Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA), revealed clear discrimination between control and treated samples, with high predictive ability for annotated discriminant metabolites. Pathway enrichment analysis unveiled prominent involvement of metabolic pathways such as nicotine and nicotinamide metabolism and valine, leucine, and isoleucine degradation. Furthermore, putatively annotated biomarkers identified through multivariate ROC curve analysis included metabolites like Thymol, Glycylproline, N-acetylglutamate, and Betaine, among others. These biomarkers, along with pathway enrichment results, underscored the intricate defense mechanisms employed by rice plants in response to M. graminicola infection. Notably, upregulated metabolites such as betaines, histamine, and 5-hydroxytryptophan were implicated in plant defense responses, while downregulated metabolites like thymol and N-acetylglutamate may contribute to increased susceptibility to nematode infection. Nicotinic acid downregulation is crucial in enhanced susceptibility of rice against M. graminicola. Pathway mapping highlighted the enrichment of crucial metabolic pathways involved in primary and secondary metabolism, emphasizing the shift from growth-related processes to defense-related responses like nicotine and nicotinamide metabolism under stress conditions. Overall, our findings provide valuable insights into the metabolic dynamics of rice plants during pathogen invasion, identifying potential biomarkers and elucidating key metabolic pathways involved in plant defense mechanisms. This research contributes to a deeper understanding of plant-nematode interactions and holds implications for the development of effective strategies for root knot management in rice cultivation.

Root knot nematode (RKN), Meloidogyne incognita, is considered a major soil-borne pathogen that can cause severe yield losses for vegetables and diverse crops. Usually, reducing of M. incognita damage is mainly relies on the application of nematicides and good agricultural practices. However, the use of synthetic nematicides is restricted due to concerns about their impact on the environment and human health. As a result, the use of alternative strategies is becoming necessary to combat RKN resistance. This study evaluates the antagonistic impact of the root mutualistic fungus Pirforomospora indica on M. incognita. It also assesses its influence on the nutritional status, photo-synthesis, antioxidant enzyme activity, endogenous abscisic acid (ABA) levels, and selected ABA related-responsive genes in cucumber plants. Roots of cucumber seedlings were inoculated with P. indica and the second-stage juveniles (1000 J2 per plant). The results demonstrated that P. indica significantly reduced M. incognita invasion in roots, resulting in a 24% reduction in root galling and 42.6% decline in final population. Inoculating plants with both P. indica and RKN increased performance of root fresh and dry weight, as well as improved photochemical efficiency of PSII (Fv/Fm), photosystem II efficiency (PSII), catalase (CAT), peroxidase (POD), and superoxide dis-mutase (SOD). Furthermore, P. indica colonization, either alone or in combination with M. incognita, significantly improved number of fruits per plant, average fruit weight, the plant's marketable yield, and leaf nutrient content (N, P, K and Mg), Moreover, there was an increase in IAA content combined with a decrease in ABA content in roots of dual inoculation plants, if compared to M. incognita infested plants. The highest ABA content was recorded in the root of RKN-cucumber plants. The decline in ABA content due to P. indica treatment was consistent with the modulation of ABA pathway genes, specifically PP2C, PYL1, RK2,1, and RK2,2. The mixed of P. indica and M. incognita led to a decrease in the expression of PP2C, PLY1, RK2,1, and RK2,2 in comparison to the control group. These results indicate that P. indica application could help reduce the negative effects of RKN on important crops.

ABSTRACTTo determine the prevalence of the four major soilborne pathogens of strawberry in the Santa Maria growing district in California, symptomatic plant samples (n = 100) were collected from 68 fields between May and September 2022. Samples comprised 28.3% of 2021 fall-planted strawberry fields and 14.0% of 2022 summer-planted strawberry fields in the district. Recombinase polymerase amplification was used to detect Macrophomina phaseolina, Fusarium oxysporum f. sp. fragariae, Verticillium dahliae, and Phytophthora spp. in plant crown material. Macrophomina phaseolina was most prevalent, detected in 52 samples, followed by Verticillium dahliae in 17 samples, F. oxysporum f. sp. fragariae in 16 samples, and Phytophthora spp. in 14 samples. Macrophomina phaseolina was more likely in eastern field locations (P = .0159) and in instances where strawberries were planted consecutively (P = .0100). Disease incidence was more likely to be higher in samples from organic fields than conventional fields (P = .0304) and in samples from flat-fumigated fields than fields fumigated in-line (P = .0124).

Carrots are highly susceptible to root-knot nematodes (RKN) which reduce their marketability due to deformation of roots. Hence, there is a need to identify resistant sources against RKN to accelerate resistance breeding programmes in carrot. In the current study, forty-eight carrot accessions were screened by artificial inoculation of nematodes to locate the lines resistant to Meloidogyne incognita. Among all, Acc- 88 was found to be immune to M. incognita followed by Acc-72, Acc-145 and KSP-123 which showed a moderately resistant reaction. Acc -113B was highly susceptible while the other 44 lines showed a susceptible reaction towards M. incognita. The accessions were validated for the Mj gene using linked molecular markers conferring resistance to RKN. The immune line, Acc-88 amplified at 266 bp proving the presence of resistance allele and Acc-113B generated the product size of the susceptible allele revealing a polymorphic difference with the ESSR0110 marker. The Mj resistance locus carrying Acc-88 has the potential to introgress RKN resistance in susceptible varieties of carrot. The validated ESSR0110 co-dominant molecular marker is promising because it could effectively distinguish resistant and susceptible individuals, thus helps the breeder to develop stable source resistance to root knot nematode. This finding is the first report on identification of immune linse and linked molecular marker in tropical carrot against M. incognita. [ABSTRACT FROM AUTHOR]

In this study, the effect of combination of three commercial bionematicides, Burkholderia rinojensis A396 strain (Majestene®), Paecilomyces lilacinus 251 strain (Bio nematon®) and Quillaja saponaria (QL-Agri®), with chitosan on gall and egg masses formed by root knot nematode Meloidogyne incognita was investigated on tomato under controlled conditions. The study was carried out in plastic pots with 9 applications of bionematicides alone and together with chitosan. A thousand Meloidogyne incognita second stage juvenile (L2)/1ml was used as nematode inoculum and the recommended doses of bionematicide applications to the field (Majestene® 0.4 ml/l, Bio nematon® 5 ml/l, Velum Prime® 0.16 ml/L, QL-Agri® 0.8 ml/L) with nematode inoculation were applied to the potting soil. Chitosan application was made 5 ml of 1% liquid suspension required for each potting soil. After sixty days, the roots were evaluated according to the index value of 1-9 gall and egg mass. The gall and egg mass index were found to be 4.2 and 3.8, respectively in only chitosan application. While the gall index changed between 3.0-4.8 in only bionematicide applications, it changed between 2.6-3.8 in combination with chitosan. As a result, the application of bionematicides together with chitosan significantly reduced the number of galls and egg masses in the roots of tomato and increased the success in the control against M. incognita. [ABSTRACT FROM AUTHOR]

India is the largest producer and exporter of basmati rice. This crop is affected by many fungal, bacterial, viral and nematode diseases. Among the nematodes, rice root-knot nematode (Meloidogyne graminicola) is considered as a major threat to the basmati rice. A pot study was undertaken to evaluate 33 promising basmati and 20 non-basmati rice varieties against the root-knot nematode. The result revealed that the varieties showed varied response to root-knot nematode. Out of 33 basmati varieties that were screened against rice root-knot nematode, minimum 27.83 galls per plant were observed in Unnat Pusa Basmati and Kasturi Basmati followed by 28.00 galls per plant in Malviya Basmati, 28.67 galls per plant in CSR 30, these four varieties showed moderately susceptible reaction against root-knot nematode and out of 20 non-basmati varieties maximum of 34.33 galls per plant were observed in Pusa Sugandh-3 followed by 33.00 galls per plant in NAHA, 32.67 galls per plant in Jamuna 804, 31.33 galls per plant in Crossa, 30.83 galls per plant in Sambha 5204 and 30.33 galls per plant in PR-420 which showed susceptible reaction against rice root-knot nematode. [ABSTRACT FROM AUTHOR]

Background: Root knot disease caused by the nematode Meloidogyne incognita (Kofoid and White) Chit wood is a serious problem in mulberry and causes severe damage to growth and development of plants. Root knot nematode alter or depletes nutritional values of mulberry leaves and adversely affects to the silkworm health in turn decreases cocoon quality and quantity. The anatomical changes in the roots due to nematode infestation affects the cocoon crop negatively, because mulberry leaves main food source for silkworm Bombyx mori L. ultimately leads to economic loss in silk industry. Methods: Hence the present study has been taken up to understand the histopathological changes that occur in the roots of mulberry V1 variety plants infested with nematode Meloidogyne incognita studied under the Scanning Electron Microscope (SEM) with an interval of 15 and 60 days after nematode inoculation. Result: After fifteen days the root samples have shown thick starchy grains were accumulated in the parenchymatous cells and intracellular movement of juveniles. Sixty days after the infested root samples had shown a number of large sized galls or knots. Ultra-structural observation of the root gall cross sections under scanning electron microscope revealed that serious anatomical changes occur in the infested mulberry root tissues. [ABSTRACT FROM AUTHOR]

Background: Plant parasitic nematodes (PPNs) are considered major agriculture pests, causing significant damage to crops by directly targeting the plant root system to prevent water and nutrient uptake. One of its major species, Meloidogyne incognita, is considered a serious threat to agriculture crop production worldwide. The current study was intended to evaluate the potential of Nanoparticles synthesized from Salix alba bark extract as nematicidal agent. Methods: Phytochemical analyses of Salix alba bark extract were conducted, and nanoparticles of the same extract were synthesized and characterized using UV-vis spectroscopy, XRD (X-Ray Diffraction), SEM (Scanning Electron Microscopy) and EDX (Energy Dispersive X-ray Spectroscopy) techniques. Results: The qualitative phytochemical analysis of Salix alba bark extract revealed the presence of phenolics, flavonoids, reducing sugars, and saponins. When applied on juveniles of the plant parasitic nematode Meloidogyne incognita, the nanoparticles demonstrated a dose and time-dependent impact. After 24 hours, the highest concentration (1000 µg/ml) of nanoparticles exhibited the greatest mortality, reaching 82.2%, while the lowest concentration resulted in a mortality rate of 34.5%. Similarly, at the 48-hour mark, the highest mortality (92.2%) was observed with 1000 µg/ml of nanoparticles, whereas the lowest concentration yielded a mortality rate of 54.5%. Extending the observation period to 72 hours, the mortality rate peaked at 98.33% with the highest nanoparticle concentration (1000 µg/ml), and the lowest mortality rate was recorded at the lowest dose, amounting to 72.5%. These results underscore the dose and time-dependent efficacy of Salix alba barkderived nanoparticles against Meloidogyne incognita. Conclusion: Our findings suggest that zinc oxide nanoparticles synthesized from Salix alba bark can be an effective agent against plant parasitic nematode Meloidogyne incognita. Further experiments are recommended to study the impact of these nanoparticles on other biotic stresses. [ABSTRACT FROM AUTHOR]

The use of arbuscular mycorrhizal fungi (AMF) offers promising benefits to agriculture in the Amazon regions, where soils are characteristically acidic and nutrient-poor. The purpose of this research was to investigate the potential effects of two recently described species of AMF (Nanoglomus plukenetiae and Rhizoglomus variabile) native to the Peruvian Amazon for improving the plant growth of Plukenetia volubilis (inka nut or sacha inchi) and protecting the roots against soil pathogens. Two assays were simultaneously conducted under greenhouse conditions in Peru. The first focused on evaluating the biofertilizer effect of AMF inoculation, while the second examined the bioprotective effect against the root knot nematode, Meloidogyne incognita. Overall, the results showed that AMF inoculation of P. volubilis seedlings positively improved their development, particularly their biomass, height, and the leaf nutrient contents. When seedlings were exposed to M. incognita, plant growth was also noticeably higher for AMF-inoculated plants than those without AMF inoculation. Nematode reproduction was significantly suppressed by the presence of AMF, in particular R. variabile, and especially when inoculated prior to nematode exposure. The dual AMF inoculation did not necessarily lead to improved crop growth but notably improved P and K leaf contents. The findings provide strong justification for the development of products based on AMF as agro-inputs to catalyze nutrient use and uptake and protect crops against pests and diseases, especially those that are locally adapted to local crops and cropping conditions.

Copyright of COMU Journal of Agriculture Faculty / ÇOMÜ Ziraat Fakültesi Dergisi is the property of Canakkale Onsekiz Mart University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Present investigation was planned to check the impact of bio (Cure, Azadirachtin) and synthetic (Cartap, Virtako) chemicals individually and concomitantly with fertilizers on the development of root knot nematode, Meloidogyne incognita and the growth of tomato (Solanum lycopersicum) plants. Tomato seedlings were transplanted in sterilized soil amended with Cartap, Virtako, Cure and Azadirachtin at their recommended doses and inoculated with 500 freshly hatched juveniles (J2s) of M. incognita. Data were recorded after 7, 14, 21 and 28 days to check the invasion and development stages. All the treatments significantly reduced invasion and subsequent development of M. incognita in roots. Different application methods regarding protective and curative were used to test the efficacy of Cartap, Virtako, Cure and Azadirachtin. Results revealed that Protective application of bio and synthetic chemicals was more effective at nematode suppression rather than being curative. Then the impact of bio and synthetic chemicals were tested in combination with NPK on nematode reproduction. Following treatments i.e. Virtako + NPK, Cartap + NPK, Cure + NPK, Azadirachtin + NPK, control (N) and control (H) with ten replications were applied in pots containing tomato seedlings. Inoculation of 2000 freshly hatched J2s of M. incognita was done. Results revealed that combined effect was more pronounced in reducing nematode reproduction and improving plant growth. Maximum number of J2s was recorded in nematode control (1241.0) while a dynamic decline was observed in Cartap+NPK, Virtako+NPK, Cure+NPK and Azadirachtin+NPK (144.4, 162.2, 198.1, 216.6) respectively. Combined application of selected chemicals with fertilizers not only reduced nematode reproduction but also improved plant growth. So, the integrated use of chemicals with fertilizers could be a successful tool in management strategies of root knot nematode. [ABSTRACT FROM AUTHOR]

Root-knot nematode (RKN) is a major factor that limits the growth and productivity of important Cucumis crops, such as cucumber and melon, which lack RKN-resistance genes in their genome. Cucumis metuliferus is a wild Cucumis species that displays a high degree of RKN-resistance. WRKY transcription factors were involved in plant response to biotic stresses. However, little is known on the function of WRKY genes in response to RKN infection in Cucumis crops. In this study, Cucumis metuliferus 60 WRKY genes (CmWRKY) were identified in the C. metuliferus genome, and their conserved domains were classified into three main groups based on multiple sequence alignment and phylogenetic analysis. Synteny analysis indicated that the WRKY genes were highly conserved in Cucumis crops. Transcriptome data from of C. metuliferus roots inoculated with RKN revealed that 16 CmWRKY genes showed differential expression, of which 13 genes were upregulated and three genes were downregulated, indicating that these CmWRKY genes are important to C. metuliferus response to RKN infection. Two differentially expression CmWRKY genes (CmWRKY10 and CmWRKY28) were selected for further functional analysis. Both CmWRKY genes were localized in nucleus, indicating they may play roles in transcriptional regulation. This study provides a foundation for further research on the function of CmWRKY genes in RKN stress resistance and elucidation of the regulatory mechanism. [ABSTRACT FROM AUTHOR]

The essential oil (EO) from the aerial parts of Mentha longifolia was obtained by hydro- [distillation method and its chemical composition was determined using GC-MS. This oil was rich in oxygenated monoterpenes (64.91 %) and sesquiterpenes hydrocarbons (1.62 %). Piperitenone oxide (62.91 %) was identified as major compound along with limonene; germacrene-D; 1, 8-cineole; piperitenone; linalool propanoate and p-mentha-1, 8-diene-2-one. Piperitenone oxide (PO) was purified from the oil using column chromatography and identified by1D and 2D NMR and GC-MS. Its EO and PO were evaluated at different concentrations (31.25 to 1000 ppm) for their nematicidal activity against M. incognita in lab conditions. These effectively killed the nematodes with LC50/96h values of 92.74 and 34.15 ppm, respectively. In pot study, they were applied to tomato plants as bare root dipping and soil drenching at 1000 and 2000 ppm under polyhouse condition. PO showed promising nematicidal activity and suppressed nematode infestation and multiplication (9.5 galls/root and 11 egg masses/root) on tomato roots compared to EO (13 galls/root and 15.5 egg masses/root) as a soil dresser at 2000 ppm with increased plant biomass and Fluopyrum 400 SC @ 500 g a.i. ha-1 (6.5 galls/root and 5.2 egg masses/root). Piperitenone oxide showed potent nematicidal activity against M. incognita for the first time and could be used as an alternate to synthetic nematicide against M. incognita. [ABSTRACT FROM AUTHOR]

Tobacco (Nicotiana tabacum L.) is one of the major nonfood crops in the Southern of Brazil. During 2019/2020 and 2020/2021 crop seasons, Root Knot Nematodes obtained from tobacco with conspicuous roots galls showed uncommon Esterase (Est Hi3) phenotypes. Morphological and biochemical assays performed a posteriori confirmed the etiologic agent of the disease is Meloidogyne hispanica with reproduction factor of 1302 ± 663,62. To our best knowledge, this is the first report of M. hispanica parasitizing tobacco in Brazil. Possible impacts in tobacco yield as well as for another plant species used in intercropping schedules must be studied in the future. Further research can be carried out to search for efficient management measures and resistant genotypes. [ABSTRACT FROM AUTHOR]

The research was carried out on a soft brown soil without carbonate at the Protected Cultivation Unit "Campo Antena" of the Socialist State Enterprise "América Libre", Santiago de Cuba, Cuba, from November 2019 to February 2020. The objective was to determine the effect of three strains of arbuscular mycorrhizal fungi (AMF) and magnetically treated water (MTW) with a stationary magnetic field on populations of Meloidogyne incognita (Kofoid and White) Chitwood and cucumber (Cucumis sativus L.) yield. AMF inoculation was carried out at planting in a proportion of 10 % of the weight of the inoculum with respect to the weight of seeds. The experimental design was completely randomized blocks, with 12 treatments and four replicates, with a control without AMF inoculation, a treatment without AMF inoculation and irrigation with MTW with magnetic induction (MI) of 0.05 - 0.07 T, a treatment without inoculation of AMF and MTW with MI of 0.10 - 0.12 T, inoculation with Rhizophagus irregularis, inoculation with Fummeliformis mosseae, inoculation with Glomus cubense and 6 treatments with inoculation of each of these AMF strains with irrigation with MTW with the two MIs under study. The variables analyzed were galling index (GI); root colonization percentage; plant height; fruit length, diameter, average weight and yield, starting from a natural infestation with a GI of 1. The data obtained were processed in the statistical package R Commander by means of a simple analysis of variance. The Tukey test for p≤ 0.05 was applied to estimate the significant differences between treatments. The results showed how effective were the treatments for the yield of cucumber, with outstanding results of the treatment with G. cubense and ATM with induction of 0.05 - 0.07 T, which reached 46.1 t.ha-1, giving the plants a greater protection against the attack of nematodes, with a final GI of 1.5. [ABSTRACT FROM AUTHOR]

The objective of the work was to evaluate the combined effect of five biochars and Trichoderma asperellum Samuels, Lieckfeldt & Nirenberg, on stimulation of tomato seedlings and their action on Meloidogyne incognita (Kofoid and White) Chitwood under semi-controlled conditions. The biochars were produced using Kon-Tiki technology. The substrates, containing: red ferralitic soil: organic fertilizer (cow manure): biochar at a 2:1:1 (w/w/w) ratio, were prepared independently. For the trial, 60-cell rooting ball trays, with 65 g of substrate each, were used. At sowing, the biochars were inoculated with a suspension of T. asperellum (Ta.13) (1x107 conidia.ml-1) at a rate of 5 ml per cell. Uninoculated controls were included for each biochar. The trays were randomly distributed. After 30 days, the following parameters were evaluated: length of plant aerial part and root, number of leaves, stem diameter, fresh weight of aerial part and root; the presence of Trichoderma in soil and root was also examined. For the study under semi-controlled conditions, five seedlings were transplanted with selected biochar+Trichoderma), and the corresponding controls, into pots containing five kg of sterile substrate (soil: cow manure, 1:1 w/w) previously inoculated with 500 juveniles (J2) from a pure population of M. incognita and left for 60 days. Finally, the above mentioned parameters and the galling index were evaluated. The mixture of rice biochar and Trichoderma was an optimal substrate with positive effects on the agronomic parameters of tomato seedlings. Compared with the control, it showed a significant reduction of the galling index in pots. [ABSTRACT FROM AUTHOR]

To determine the prevalence of the four major soilborne pathogens of strawberry in the Santa Maria growing district in California, symptomatic plant samples (n = 100) were collected from 68 fields between May and September 2022. Samples comprised 28.3% of 2021 fall-planted strawberry fields and 14.0% of 2022 summer-planted strawberry fields in the district. Recombinase polymerase amplification was used to detect Macrophomina phaseolina, Fusarium oxysporum f. sp. fragariae, Verticillium dahliae, and Phytophthora spp. in plant crown material. Macrophomina phaseolina was most prevalent, detected in 52 samples, followed by Verticillium dahliae in 17 samples, F. oxysporum f. sp. fragariae in 16 samples, and Phytophthora spp. in 14 samples. Macrophomina phaseolina was more likely in eastern field locations (P =.0159) and in instances where strawberries were planted consecutively (P =.0100). Disease incidence was more likely to be higher in samples from organic fields than conventional fields (P =.0304) and in samples from flat-fumigated fields than fields fumigated in-line (P =.0124). [ABSTRACT FROM AUTHOR]

Copyright of Arab Journal of Plant Protection is the property of Arab Society for Plant Protection and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background Essential oils from aerial parts of Achillea wilhelmsii, Tanacetum polycephalum and Teucrium polium were isolated by using Clevenger-type apparatus and tested at different concentrations for their nematicidal activity against the second stage juvenile (J2) of Meloidogyne incognita in vitro condition. The chemical components of the essential oils and seed extracts of each plant (0.2 g) were extracted with maceration with methanol/acetic acid mixture (85:15, v/v). Analysis was done by Gas Chromatography, GC-Mass Spectrometry) and HPLC. Identified chemical components were tested after this on J2 of M. incognitain. Nuclear magnetic resonance spectroscopy was done to investigate the properties of organic molecules by drawing their spectrum using Broker AVANCE AQS-300 MHz. Results Significant difference was achieved on nematicidal activity of essential oils based on the plant species and oil concentrations. GC and GC–MS led to identification of 41, 39 and 45 major compounds from T. polium, T. polycephalum and A. wilhelmsii oils, respectively. A number of 10 components with different ranges of percentage were recorded in all of the tested plants oils. Use of HPLC resulted in identification of 4, 3 and 2 chemical compounds in the extracts of A. wilhelmsii, T. polycephalum and T. polium, respectively. The nematicidal activity of commercial polyphenols at the concentration of 1100 ppm showed 58.3, 48.9, 28.2 and 26.8 percentages J2 mortalities by catechin, coumarin, gallic acid and chlorogenic, respectively. Nematotoxicity test of commercial terpenoids showed the highest J2 mortalities (more than 80%), in concentrations of 100 and 200 ppm limonene, β-pinene and α-pinene. However, it was less than 30% of J2 mortality caused by terpinen-4-ol, α-terpineol and linalool. Conclusions Compounds such as Limonene, β-pinene and α-pinene were detected in all of the tested plants, A. wilhelmsii, T. polycephalum and T. polium, having an effective nematicidal action versus terpinen-4-ol, α-terpineol and linalool.

Root knot nematode (Meloidogyne incognita) cause major damage to the fruit crops, vegetable crops and field crops. Infected plants showed declined symptoms and poor fruit yield also displayed stunting and yellowing symptoms. In order to choose appropriate management control techniques, nematode diagnosis and specimen identification must be accurate, quick and precise. The population of the nematode obtained from the experimental field of Post Graduate Institute, Mahatma Phule Krishi Vidyapeeth, Rahuri were assessed for their host-race status by the differential host test which relies on the combination of resistant and susceptible reactions of six differential hosts to the nematode population. Result revealed that the nematode population infected tobacco (NC 95), pepper (California Wonder), watermelon (Charleston grey), tomato (Rutgers) and unable to reproduce on cotton (Deltapine-16) and peanut (Florunner) which indicated presence of race 2 of Meloidogyne incognita. [ABSTRACT FROM AUTHOR]

Copyright of Mustafa Kemal University Journal of Agricultural Sciences / Mustafa Kemal Üniversitesi Tarım Bilimleri Dergisi is the property of Mustafa Kemal University, Faculty of Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The ongoing prominence of tomato (Solanum lycopersicum L.) as a vegetable and salad product is evident in the considerable body of studies on virtually all areas of the crop. However, various biological stressors are substantially hindering tomato productivity, presenting a major obstacle to forecasting future expectations of something like the developing world. Root-knot nematodes (RKN) are a significant threat to agricultural productivity among many biotic challenges. Beyond inflicting physical harm, it contributes as an exacerbating agent for the introduction of bacterial and fungal pathogens, compounding the situation and attributed to the creation of disease structures. Current management methods are insufficient to completely regulate RKN. Although the management of this nematode pest is primarily using chemical nematicides, however, phase out of the synthetic chemicals due to its harmful potential danger on living creatures as well as the environment, this same problem of root-knot nematodes intensified and become a significant impediment for the successful cultivation of vegetable crops in an open field as well as protected cultivation. In the present review paper, and efforts have been made to clarify the plethora of integrated approaches including genetics-based techniques for the control of root-knot nematodes in tomatoes. [ABSTRACT FROM AUTHOR]

In this study, the interaction of Bacillus subtils, B. cereus, and Pseudomonas fluorescens CHA0 with the bacteriovorus nematode Caenorhabditis elegans was investigated in in-vitro condition. Possibilities of the survival and reproduction, the attraction and feeding of C. elegans on the bacteria, and the effect of volatile compounds and antibiotics of the bacteria on C. elegans were examined. The efficiency of the bacteria on controlling Meloidogyne javanica was studied by evaluating the number of galls and egg masses per plant, gall-diameter per plant, and the number of eggs per egg mass. Then, the most effective bacterium was used for the induction of plant defence responses. The results showed that C. elegans is not able to survive and reproduce on the colony of B. cereus and P. fluorescens CHA0. Although, in the normal condition, C. elegans did not feed on B. cereus, when the nematode was left hungry it started to eat the bacterium which, however, caused its death. Volatile compounds and antibiotics of B. cereus and P. fluorescens CHA0 caused 100% C. elegans larval mortality after 24 or 48 hours. All three bacteria caused a significant reduction (p<0.05) in all indicators of M. javanica pathogenicity while the highest efficacy in controlling the nematode was observed for P. fluorescens CHA0. Biochemical analyses showed that inoculating plants with P. fluorescens CHA0 and/or M. javanica caused a significant increase (p<0.05) of catalase in the plants. [ABSTRACT FROM AUTHOR]

Background: Essential oils from aerial parts of Achillea wilhelmsii, Tanacetum polycephalum and Teucrium polium were isolated by using Clevenger-type apparatus and tested at different concentrations for their nematicidal activity against the second stage juvenile (J2) of Meloidogyne incognita in vitro condition. The chemical components of the essential oils and seed extracts of each plant (0.2 g) were extracted with maceration with methanol/acetic acid mixture (85:15, v/v). Analysis was done by Gas Chromatography, GC-Mass Spectrometry) and HPLC. Identified chemical components were tested after this on J2 of M. incognitain. Nuclear magnetic resonance spectroscopy was done to investigate the properties of organic molecules by drawing their spectrum using Broker AVANCE AQS-300 MHz. Results: Significant difference was achieved on nematicidal activity of essential oils based on the plant species and oil concentrations. GC and GC-MS led to identification of 41, 39 and 45 major compounds from T. polium, T. polycephalum and A. wilhelmsii oils, respectively. A number of 10 components with different ranges of percentage were recorded in all of the tested plants oils. Use of HPLC resulted in identification of 4, 3 and 2 chemical compounds in the extracts of A. wilhelmsii, T. polycephalum and T. polium, respectively. The nematicidal activity of commercial polyphenols at the concentration of 1100 ppm showed 58.3, 48.9, 28.2 and 26.8 percentages J2 mortalities by catechin, coumarin, gallic acid and chlorogenic, respectively. Nematotoxicity test of commercial terpenoids showed the highest J2 mortalities (more than 80%), in concentrations of 100 and 200 ppm limonene, β-pinene and α-pinene. However, it was less than 30% of J2 mortality caused by terpinen-4-ol, a-terpineol and linalool. Conclusions: Compounds such as Limonene, β-pinene and α-pinene were detected in all of the tested plants, A. wilhelmsii, T. polycephalum and T. polium, having an effective nematicidal action versus terpinen-4-ol, α-terpineol and linalool. [ABSTRACT FROM AUTHOR]

Root knot nematode (Meloidogyne incognita) cause major damage to the fruit crops, vegetable crops and field crops. Infected plants showed declined symptoms and poor fruit yield also displayed stunting and yellowing symptoms. In order to choose appropriate management control techniques, nematode diagnosis and specimen identification must be accurate, quick and precise. The population of the nematode obtained from the experimental field of Post Graduate Institute, Mahatma Phule Krishi Vidyapeeth, Rahuri were assessed for their host-race status by the differential host test which relies on the combination of resistant and susceptible reactions of six differential hosts to the nematode population. Result revealed that the nematode population infected tobacco (NC 95), pepper (California Wonder), watermelon (Charleston grey), tomato (Rutgers) and unable to reproduce on cotton (Deltapine- 16) and peanut (Florunner) which indicated presence of race 2 of Meloidogyne incognita.

The movement of plant-parasitic nematodes in soil is influenced by the soil environment and the microorganisms present in it, and soil conditions affect disease incidence. The objective of this study was to investigate the movement of second-stage juveniles of the root-knot nematode Meloidogyne incognita 18 weeks after incubation with vermicompost under constant saturation flow 24 and 72 hours after the nematodes were added to the soil in a horizontal pipe. The experiment was conducted as a factorial experiment with a completely randomized design in three replicates. The nematodes were extracted by the tray method and then counted. The results showed that 24 hours after the nematodes were injected into the control soil, the highest nematode population was observed at the injection site and the nematodes moved more toward the water flow. 72 hours after injection, a higher percentage of them moved and the nematode population decreased at the injection site (1.52%). Also, in the soil treated with vermicompost for 18 weeks, nematodes moved both in and against the direction of water flow 24 hours after injection and were distributed at all points of the pipe. The highest rate of nematode movement was observed at point (-4) at 14%. At 72 hours after injection, the nematodes were also very evenly distributed in the pipe and the number of nematodes that entered the wastewater was higher. [ABSTRACT FROM AUTHOR]

The effect of two isolates of fungi (Glomus mosseae - Trichoderma harzianum); two isolates of bacteria (Azotobacter chroococcum - Pseudomonas fluorescens), and two nematodes (Steinernema feltiae- Diplogaster lheritieri) was evaluated against root knot nematode, Meloidogyne incognita infecting tomato plants under greenhouse conditions. The experiment was conducted in plastic pots (25 cm) at the Research Station of the Faculty of Agriculture in Shebin El-kom, El-Menoufia Governorate. Statistical analysis of the obtained results recorded that predatory nematode, D. lheritieri gave the highest reduction percentage (84.0%) in M. incognita juveniles, as well as it reduced root gall index (60.0%) and mature females (72.3%), compared to the nematicide oxamyl that gave 84.2 & 80.0 %, respectively. Triple treatment of D. lheritieri + A. chroococcum + G. mosseae was superior recording only 184.7 J2 / 100 cm3 soil with a reduction percentage of 88.5 % compared to the rest of bio-agents. From the obtained results, it can be recommended to use such treatment which achieved the highest decrease percentages of soil nematodes, number of females and root knot galls compared to oxamyl. [ABSTRACT FROM AUTHOR]

[ Objective ] The correlation between the occurrence and harm of buckwheat root knot nematode and the previous crops and Tartary buckwheat yield in Southwest China was studied, which could provide a theoretical basis for the rational distribution of Tanary buckwheat production and the green prevention and control of root knot nematode in this area. [ Method ] Tanary buckwheat was used as experimental material, and field investigation and artificial inoculation experiment were used to analyze the correlation between root knot nematode damage and previous crops and yield of Tanary buckwheaL [ Result] The results showed that when the previous crop was tobacco, the occurrence and harm of buckwheat root knot nematode was the most serious, and the incidence rate was 60. 47% and the disease index was 23. 25. The second was cabbage, the incidence rate was 11. 95% and the disease index was 3. 31. when previous crops was maize,potato, maize and potato interplanting, rapeseed and pepper, respectively the root knot nematode was less harmful, the incidence rate was less than 5 % and the disease index was less than 1. 00. No harm of root knot nematode was found in Maca and fallow land. The linear correlation equations of disease grade and disease index of root knot nematode to yield of Tanary Buckwheat were y = - 0. 4175x + 3. 086, R² = 0. 1473, y = - 4. 604x + 600. 35, R² = 0. 1652, respectively. The a values of the two equations were - 0. 4175 and - 4. 604, the R² values were 0. 1473 and 0. 1652, respectively. [ Conclusion ] The occurrence and harm of buckwheat root knnematode were closely related to the previous crops. Among them, the root knot nematode was the most harmful when planting Tartary buckwheat after tobacco, and there was no root knot nematode disease in Maka and leisure land Although the effect of root knot nematode disease on the yield of Tartary buckwheat was negatively correlated, the correlation was low. [ABSTRACT FROM AUTHOR]

In the last two decades many developments have been occurred which triggered the prospects and opportunities for the biological control of plant-parasitic nematodes. Due to health and environmental concerns several chemical nematicides have been withdrawn from the market and revealed interest in the development of alternative methods of control, including the use of biocontrol agents. In the present study biocontrol potential of the parasitic fungus Paecilomyces lilacinus isolated from four different agro climatic zones of India was evaluated for the management of root-knot nematode Meloidogyne incognita under laboratory and field conditions. Many isolates were collected from the rhizosphere of root-knot nematode affected vegetables fields during year 2003 - 2005 and four different isolates representing the best among the collected isolates from each zone was tested in vitro for their larvicidal, ovicidal and egg-parasitizing capacity against M. incognita. Fungal isolates were grown in Potato dextrose broth and filtered to remove fungal biomass. Toxins responsible for the nematicidal action was extracted from culture filtrate and tested for their potentiality. Methanol extracted toxins were found to be more lethal in comparison to the other organic solvents. In field experiments, various developed formulations of P. lilacinus were found effective and significantly suppressed the root-knot nematode. These tests revealed variability in their potentiality and activity against root knot nematode. Identified isolates of P. lilacinus were found capable to produce bioactive nematicidal compounds against root-knot nematode M. incognita. [ABSTRACT FROM AUTHOR]

Summary: Phytohormones may affect plant–nematode interactions directly as chemo‐attractants or ‐repellents, or indirectly through the root‐associated microbiome or through host defense mechanisms. However, the exact roles of phytohormones in these complex plant–soil–nematode interactions are not well understood.We used Arabidopsis thaliana mutants impaired in phytohormone synthesis or sensitivity to elucidate their role in root–nematode interactions. As root‐associated microorganisms may modulate these interactions, we explored correlations between the relative abundances of root‐associated nematodes, and bacteria and fungi using amplicon sequencing.We found distinct shifts in relative abundances of a range of nematode taxa in the A. thaliana phytohormone mutants. The root knot nematode Meloidogyne hapla, a sedentary endoparasitic species that is in intimate contact with the host, was highly enriched in JA‐, SA‐ and SL‐impaired lines, and in an ET‐insensitive line. Positive or negative correlations between specific microbial and nematode taxa were observed, but, as the inference of causal relationships between microbiome responses and effects on nematode communities is premature, this should be studied in detail in future studies.In conclusion, genetic derailment of hormonal balances generally rendered plants vulnerable to endoparasitic nematode attack. Furthermore, preliminary data suggest that this effect may be partially modulated by the associated microbiome. [ABSTRACT FROM AUTHOR]

The root-knot nematode (RKN; Meloidogyne incognita) and reniform nematode (RN; Rotylenchulus reniformis) reduce Upland cotton (Gossypium hirsutum) yields nearly 5% annually throughout the United States. Recent work has proved successful in transferring the chromosome 11 (Chr11) and 14 RKN resistance QTL and the chromosome 21 Renbarb2 RN resistance QTL into elite Upland cultivars. The deployment of a limited number of resistance QTL risks the creation of virulent nematode populations; therefore, we set out to phenotypically and genotypically re-evaluate wild G. hirsutum and G. barbadense accessions that had previously been labeled as resistant to RKN and/or RN. Twenty-six (26) G. hirsutum accessions were evaluated for RKN resistance and were genotyped using SSR and SNP markers that corresponded to the Chr11 and Chr14 QTL. Accessions showed a range of RKN resistance phenotypes as measured by eggs g−1 root, gall score, and reproductive factor; however, genotypic analyses revealed that all resistant accessions carried either the Chr11 or Chr14 resistance QTL. For RN resistance, G. hirsutum and G. barbadense accessions were investigated. Genotyping of sixteen (16) G. barbadense accessions with the SSR marker BNL3279 that is linked to the Renbarb2 QTL revealed that resistance in these accessions was due to an allele of Renbarb2. Twenty-one (21) G. hirsutum accessions were evaluated for RN resistance as measured by eggs g−1 root, vermiform nematodes g−1 soil, and reproductive factor. None of the G. hirsutum accessions showed a consistent resistant phenotype across multiple experiments. Our findings emphasize the importance of screening new genetically diverse cotton populations in order to find novel sources of RKN and RN resistance. [ABSTRACT FROM AUTHOR]