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Meloidogyne incognita (root-knot nematode) is one of the most destructive pests of crops worldwide. Injudicious use of synthetic nematicides has led to environmental toxicity, development of resistance, and disruption of ecological balance, necessitating the need for safer and effective alternatives. Essential oil from Mentha spicata (Spearmint) has been reported to have nematicidal activity but the activity of its polar constituents is unexplored against the nematodes, infesting agricultural crops. Six compounds, stigmasterol (1), β-sitosterol-3-O-β-D-glucoside (2), 3β,13β-dihydroxy-urs-11-en-28-oic acid (3), 5,6-dihydroxy-7,8,4′-trimethoxyflavone (4), 5,6,4′-trihydroxy-7,8,3′-trimethoxyflavone (5), and 5,6,4′-trihydroxy-7,8-dimethoxyflavone (6), were isolated from methanolic extract of Mentha spicata (spearmint) and identified by NMR (1D & 2D) spectral analysis. Compound 3 was identified for the first time from genus Mentha. In vitro nematicidal activity of pure compounds (2 and 4–6) was carried out against Meloidogyne incognita, and results showed significant mortality (LC50 values ranging between 62.64 and 74.19 ppm after 96 h). Molecular docking study revealed the favourable binding of the test compounds with acetylcholinesterase enzyme, facilitated by H-bond, electrostatic interactions, and hydrophobic interactions. The binding energy of the tested compounds with the target protein was found highest in 5 (− 10.0 kcal/mol) and 6(− 9.9 kcal/mol) followed by 2 (− 9.2 kcal/mol) and 4 (− 8.9 kcal/mol). The minimum binding energy was recorded in carbofuran (−7.5 kcal/mol), a positive control, and was also corroborated with in vitro nematicidal activity. This study showed the potent nematicidal activity of compounds (2 and 4–6), which can be further used for the development of nematicides against M. incognita in agriculture. [ABSTRACT FROM AUTHOR]

Potato cyst nematodes (PCNs) pose a great challenge for potato cultivation throughout the world. Being a rather difficult parasite due to a number of its physiological features, specifically a long-term viability of the eggs, PCN causes drastic damage to worldwide agriculture. Development of long-acting preparations deposited with nematicidal ingredients could be a novel prospective approach to PCNs management. In this study, composite granules based on polycaprolactone and montmorillonite (PCL/MMT) (100:0; 90:10; 75:25; 50:50) were studied as carriers for oxamyl nematicide. It was shown that the obtained granules are able to postpone the hydrolysis of oxamyl from 17 to 27 days and facilitate its gradual release. The maximum release of oxamyl in water was noted for PCL/MMT 50% granules and amounted to 70.3 µg/ml on day 14. Meanwhile, oxamyl release in soil had relatively the same trend for all the granules with the most release in the first 20 days. Kinetic models demonstrated that for all PCL/MMT granules the release was due to diffusion mechanism. The nematicidal effect of PCL/MMT 50% granules with oxamyl against G. rostochiensis has been demonstrated on potato variety "Krasnoyarskiy ranniy". [ABSTRACT FROM AUTHOR]

Pathogenic fungi employ numerous strategies to colonize plants, infect them, reduce crop yield and quality, and cause significant losses in agricultural production. The increasing use of chemical pesticides has led to various ecological and environmental issues, including the emergence of resistant weeds, soil compaction, and water pollution, all negatively impacting agricultural sustainability. Additionally, the extensive development of synthetic fungicides has adverse effects on animal and human health, prompting the exploration of alternative approaches and green strategies for phytopathogen control. Microorganisms living in sponges represent a promising source of novel bioactive secondary metabolites, potentially useful in developing new nematicidal and antimicrobial agents. This study focuses on extracting bioactive compounds from endosymbiotic bacteria associated with the marine sponge Hyrtios erect sp. (collected from NIOF Station, Hurghada, Red Sea, Egypt) using various organic solvents. Bacillus sp. was isolated and identified through 16 S rRNA gene sequencing. The biocidal activity of Bacillus gotheilii MSB1 extracts was screened against plant pathogenic bacteria, fungi, and nematodes. The n-butanol extract showed significant potential as a biological fungicide against Alternaria alternata and Fusarium oxysporum. Both n-hexane and ethyl acetate extracts exhibited negative impacts against the plant pathogenic bacteria Erwinia carotovora and Ralstonia solanacearum, whereas the n-butanol extract had a positive effect. Regarding nematicidal activity, ethyl acetate and n-butanol extracts demonstrated in-vitro activity against the root-knot nematode Meloidogyne incognita, which causes serious vegetable crop diseases, but the n-hexane extract showed no positive effects. The findings suggest that bioactive compounds from endosymbiotic bacteria associated with marine sponges, particularly B. gotheilii MSB1, hold significant potential as alternative biological control agents against plant pathogens. The n-butanol extract, in particular, displayed promising biocidal activities against various plant pathogenic fungi, bacteria, and nematodes. These results support further exploration and development of such bioactive compounds as sustainable, environmentally friendly alternatives to synthetic pesticides and fungicides in agricultural practices. [ABSTRACT FROM AUTHOR]

Background: In the South of Russia, due to the large acreage of tomato crops (Solanum lycopersicum Mill.), there is an acute problem of plant protection against the obligate endoparasitic of the root system Meloidogyne hapla Chitwood 1949. The aim of this study was to assess the nematicidal activity of fungal strains isolated from the rhizosphere of tomato plants infected with root-knot nematodes (RKN) (Meloidogyne spp.). Results: After conducting route surveys, 10 soil samples were selected from the rhizosphere of tomato plants affected by RKN. Fifteen isolates of fungi belonging to different species were isolated from the soil samples. The species composition of the isolated fungal strains was determined: Metarhizium anisopliae IG01, Penicillium citrinum IG02, Trichoderma harzianum IG03, Aspergillus niger IG04, Trichoderma ghanense IG05, Trichoderma harzianum IG06, Trichoderma atroviride IG07, Aspergillus awamori IG08, Trichoderma atroviride IG09, Paramyrothecium roridum IG10, Trichoderma atroviride IG11, Trichoderma hamatum IG12, Beauveria bassiana IG13, Aspergillus ochraceus IG14, Purpureocillium lilacinum IG15. After initial screening in the laboratory, strains with the greatest nematicidal activity and safe for humans were selected: M. anisopliae ИГ01, T. harzianum IG03, T. ghanense IG05, T. atroviride IG07, T. atroviride IG09. The mortality rate of RKN when using these fungal strains varied from 79.4 ± 1.8 to 93.9 ± 3.1%. In the greenhouse, the fungal strains M. anisopliae IG01, T. harzianum IG03, T. ghanense IG05, T. atroviride IG07, T. atroviride IG09 showed high results in reducing the number of galls on the roots of tomato plants, and their biological efficacy was 71.4–83.0%. Conclusion: Work on the study of the nematicidal activity of fungi, in vitro and in vivo, allows us to conclude that strains isolated from the rhizosphere of plants can be effective in combating the north RKN (M. hapla). In the future, it is planned to establish the compatibility of M. anisopliae IG01, T. harzianum IG03, T. ghanense IG05, T. atroviride IG07, T. atroviride IG09 with each other and selecting the ratios of the studied strains to obtain mixtures to create an effective biological nematicide. [ABSTRACT FROM AUTHOR]

Sediment is the ultimate sink of environmental pollutants. A total of 128 surface sediment samples were collected from 8 rivers and 3 reservoirs in Maoming City, Guangdong Province. This study assessed the content and distribution of brominated flame retardants in sediments. The acute toxicity effects of tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDs) in sediments were evaluated using Caenorhabditis elegans as model organisms. The concentration of TBBPA in sediments ranged from not detected (ND) to 12.59 µg/kg and was mainly distributed in the central area, which was affected by the emission of TBBPA from residential and factory. The concentration of HBCDs ranged from ND to 6.31 µg/kg, and the diastereoisomer distribution was consistent, showing a trend close to the South China Sea. The composition pattern of HBCDs in the surface sediments from rivers were 41.73%–62.33%, 7.89%–25.54%, and 18.76%–40.65% for α-, β-, and γ-HBCD, respectively, and in the sediments from reservoirs were 26.15%–45.52%, 7.44%–19.23%, and 47.04%–61.89% for α-, β-, and γ-HBCD, respectively. When the sum of concentrations of TBBPA and HBCD in sediments were above high levels, reactive oxygen species in nematodes significantly increased, resulting in an oxidative stress response. Intestinal permeability was also enhanced, causing intestinal damage. In addition, in terms of this study, TBBPA had a greater impact on biotoxicity compared to HBCDs, and more attention should be paid to the toxic effects of the river ecosystem organisms in Maoming City, Guangdong Province. This study can complement the pollution database in the study area and provide basic data for pollution control. [Display omitted] [ABSTRACT FROM AUTHOR]

The root-knot nematode Meloidogyne enterolobii is a major constraint to pepper production in tropical regions. In the long-term practice of root-knot nematode management, bacterial nematicides have attracted increasing attention as effective biocontrol agents. In this study, we evaluated the efficacy of Bacillus thuringiensis strain 00-50-5 (Bt 00-50-5) against M. enterolobii through in vitro, greenhouse and field trials. The cell-free supernatant of Bt 00-50-5 exhibited potent nematicidal activity against second-stage juveniles (J2s) of M. enterolobii, with mortality rates of 98.0% and 100% after 24 h and 36 h of exposure, respectively. In addition, Bt 00-50-5 showed inhibitory effects on the hatching of M. enterolobii eggs, resulting in a remarkable 96.6% reduction in the egg hatching rate after 6 days compared to the control. The pot trials showed that both pepper root galls and egg masses were reduced, and plant growth was improved after treatment with Bt 00-50-5. The field trials showed that the gall index was significantly reduced, with a 66.3% and 68.2% reduction in disease index in 2020–2021 and 2021–2022, respectively, and pepper yield was improved, with a 96.2% and 93.1% increase in yield in 2020–2021 and 2021–2022, respectively, compared to the control. These results indicate the potential use of Bt 00-50-5 as an effective biocontrol agent against M. enterolobii. [ABSTRACT FROM AUTHOR]

Root-knot nematodes (RKNs) are considered a limiting factor for tomato production, causing substantial economic losses. Several control measures have been used to control RKNs in infested areas, such as crop rotation or succession with non-host species, using resistant cultivars, and applying chemical and biological nematicides. Here, we examined the control effect of six microbiological products (Ag109 - Bacillus velezensis, Votivo Prime - B. firmus, Quartzo - B. subtilis and B. licheniformis, Veraneio - B. amyloliquefaciens, Nemat - Purpureocillium lilacinum, and Rizotec - Pochonia chlamydosporia) against different species of Meloidogyne in tomatoes cultivated in a greenhouse and evaluated these products under field conditions to verify their impact on rootassociated nematode populations and agronomic and physicochemical traits of fruits from grafted and non-grafted tomato plants. For the greenhouse studies, higher pathogenicity was observed for tomato with M. javanica and M. enterolobii compared to M. incognita. The microbiological nematicides were more effective in controlling M. javanica and M. enterolobii, while for M. incognita, the evaluated products were ineffective. Regarding the field studies, most of the microbiological nematicides evaluated effectively increased production per plant. However, when analyzing the Meloidogyne population in the field, applying microbiological nematicides showed no nematode control in plants without rootstock. On the other hand, in the grafted plants, the Ag109, Veraneio, Rizotec, and Nemat treatments boosted the reduction in the Meloidogyne population in the roots, with average reductions of 68.47, 57.97, 77.29, and 56.70%, respectively. These results indicate the effectiveness of integrated management of microbiological nematicides and resistant rootstock in tomato. Furthermore, combining these two control measures resulted in no change in the nutritional quality of tomato fruits. [ABSTRACT FROM AUTHOR]

Bacillus species are among the most studied and commercially exploited biocontrol agents of plant‐parasitic nematodes. These antagonists may control nematodes by producing toxic or repellent substances, inducing systemic resistance in plants and disrupting nematode chemotaxis. Understanding the mechanism of action of antagonists increases the likelihood of success for microbiological nematicides under field conditions. Therefore, the objective of this work was to elucidate the mechanisms of action of Bacillus amyloliquefaciens strain BaNCT02 against Meloidogyne incognita. We assessed the potential of this strain for forming biofilm in roots and producing volatile and non‐volatile toxic substances. BaNCT02 did not induce systemic resistance in tomato plants against M. incognita. Scanning electron microscopy and chemotaxis analyses revealed that the bacteria form a biofilm on soybean roots and 67% of second‐stage juveniles of M. incognita are repelled by common bean roots treated with the antagonist. Additionally, BaNCT02 produces substances with toxic effects against eggs and juveniles of M. incognita, including volatile organic compounds such as 2‐undecanone and 2‐heptanone, as well as non‐volatile metabolites like proteases and chitinases. The suppressive effect of these substances on hatching and mortality of juveniles varied from approximately 70% to more than 90%. We concluded that B. amyloliquefaciens BaNCT02 forms a biofilm on root surfaces and produces volatile and non‐volatile metabolites with nematicidal and repellent effects against M. incognita. [ABSTRACT FROM AUTHOR]

A crude hexane extract of seed kernel was processed into fatty acid methyl esters (FAME) using methanolic-sulfuric acid. Herbal mixtures (seed extracts of A. squamosa and essential oils of Cymbopogon nardus (citronella) and Pelargonium graveolens (geranium)) were evaluated against root knot nematode (Meloidogyne spp). The mortality of J2s of M. incognita in hexane and methanol extracts (AHE+AME) of A. squamosa with geranium oil (GO) ranged from 50.75-89.75% to 71.50-99.00% at 31.25 to 1000 μgmL-1 in 24 to 96 hours. The number of galls after CO+AHE+AME treatment was 4.0 ± 0.0 and 5.67 ± 0.58 galls/seedling and were recorded at 1000 and 500 μgmL-1 treatments on 30 days after inoculation, compared to carbofuran (3.0 ± 0.0 and 4.3 ± 0.6 galls/seedling) at 1000 and 500 μgmL-1 and velum prime (3.6 ± 0.6 and 4.6 ± 0.6 galls/seedling) at 1000 and 500 μgmL-1. The maximum shoot length of brinjal seedlings was recorded in CO+AHE+AME treatment compared to carbofuran (47.3 ± 0.6cm) and velum prime (48.7 ± 0.6 cm) at 1000 μg mL-1 in soil drenching application. Methanol and hexane extracts (AHE+AME) obtained from Annona squamosa seeds were investigated for their nematicidal properties. M. graminicola in direct-seeded rice at the nursery level and M. incognita in brinjal (eggplant) were controlled for up to sixty days when treated with these mixtures. [ABSTRACT FROM AUTHOR]

Root-knot nematodes pose a persistent threat to various economically important crops in Thailand, with limited available management strategies for farmers. This study aimed to assess the efficacy of aqueous (AE), methanolic (ME), ethanolic (EE), ethyl acetate (EAE), and chloroform (CE) crude extracts derived from green chiretta in controlling Meloidogyne enterolobii and M. incognita under laboratory conditions. The results demonstrated significant inhibitory effects of all crude extracts, except for CE, against both nematode species. Notably, AE (10 and 20 mg/mL), ME (20 mg/mL), and EE (20 mg/mL) treatments exhibited maximum inhibition of hatching, leading to a considerable reduction in nematode hatch rates by 87.5 - 96.8 % for M. enterolobii and 88.5 - 96.5 % for M. incognita, compared with distilled water (DW). In terms of second-stage juveniles (J2s) mortality, AE (10 and 20 mg/mL), ME (20 mg/mL), and EAE (20 mg/mL) demonstrated the highest nematicidal activity, resulting in mortality rates of 94.2 - 100 % for M. enterolobii and 92.2 - 99.2 % for M. incognita. Chemotaxis assays revealed a repellent effect of all extracts on both nematode species, except for the ethyl acetate extract (EAE), which attracted M. incognita J2s without affecting M. enterolobii J2s. The observed efficacy was attributed to the higher concentrations of bioactive compounds, including flavonoids, phenolics, and terpenoids, in the extracts compared to CE. Based on these in vitro findings, it is suggested that AE, ME, EE, and EAE of green chiretta exhibit significant nematicidal activity against M. enterolobii and M. incognita. Further evaluation under greenhouse and field conditions is warranted to ascertain the practical applicability and effectiveness of these extracts in a real-world agricultural setting. [ABSTRACT FROM AUTHOR]

The search for natural product-based biopesticides from endophytic fungi is an effective tool to find new solutions. In this study, we studied a pre-selected fungal endophyte, isolate YCC4, from the paleoendemism Persea indica, along with compounds present in the extract and the identification of the insect antifeedant and nematicidal ones. The endophyte YCC4 was identified as Phyllosticta sp. by molecular analysis. The insect antifeedant activity was tested by choice bioassays against Spodoptera littoralis, Myzus persicae, and Rhopalosiphum padi, and the in vitro and in vivo mortality was tested against the root-knot nematode Meloidogyne javanica. Since the extract was an effective insect antifeedant, a strong nematicidal, and lacked phytotoxicity on tomato plants, a comprehensive chemical study was carried out. Two new metabolites, metguignardic acid (4) and (-)-epi-guignardone I (14), were identified along the known dioxolanones guignardic acid (1), ethyl guignardate (3), guignardianones A (5), C (2), D (7), and E (6), phenguignardic acid methyl ester (8), the meroterpenes guignardone A (9) and B (10), guignarenone B (11) and C (12), (-)-guignardone I (13), and phyllomeroterpenoid B (15). Among these compounds, 1 and 4 were effective antifeedants against S. littoralis and M. persicae, while 2 was only active on the aphid M. persicae. The nematicidal compounds were 4, 7, and 8. This is the first report on the insect antifeedant or nematicidal effects of these dioxolanone-type compounds. Since the insect antifeedant and nematicidal activity of the Phyllosticta sp. extract depend on the presence of dioxolanone components, future fermentation optimizations are needed to promote the biosynthesis of these compounds instead of meroterpenes. [ABSTRACT FROM AUTHOR]

Pine wilt disease, caused by Bursaphelenchus xylophilus (Steiner & Buhrer, 1934) Nickle 1981, poses a significant threat to the safety of pine forests in the world. Currently, the available nematicides for controlling this disease are limited. Finding new nematicides is crucial for the effective prevention and control of pine wilt disease. In this study, we discovered that tetramycin B3, derived from Streptomyces ahygroscopicus, demonstrated a promising effect on pine wilt disease. The LC50 values of tetramycin B3 at 24, 48, and 72 h were 26.49, 23.37, and 12.79 μg/mL, respectively. Tetramycin B3 significantly inhibited the feeding and growth rate of B. xylophilus at low concentrations while also increasing ROS (reactive oxygen species) production and lipid accumulation. Furthermore, tetramycin B3 markedly inhibited the activity of detoxifying and protective enzymes. Transcriptome and metabolome analyses indicated that tetramycin B3 significantly affected the expression of genes related to lysosomes, autophagy, and lipid metabolism in B. xylophilus. Additionally, tetramycin B3 delayed the onset of pine wilt disease. Transcriptome results showed that tetramycin B3 significantly influenced the expression of genes related to defense responses in pine trees and induced pine trees to produce disease-resistant mechanisms. Future research will focus on further elucidating the mechanism of action of tetramycin B3 against B. xylophilus and verifying the gene functions identified through transcriptome screening. [ABSTRACT FROM AUTHOR]

BACKGROUND: Although microencapsulation technology is an effective pesticide formulation method, the correlation between the release properties of microcapsules and pesticide concentrations in soil and their efficacy has not been thoroughly investigated. Here, the effects of the release properties of the nematicide Fosthiazate (FTZ) from microcapsules on their efficacy against the nematode Meloidogyne incognita were examined using experimental and mathematical approaches. RESULTS: Gradual release of FTZ from both polyurea microcapsules (PU‐MC) and melamine‐formaldehyde microcapsules (MF‐MC) was observed over 30 days in the release test, and each release curve was completely distinct. In the biological test, the efficacy of both microcapsules against M. incognita 42 days after the application was 8–15% higher than that of the non‐encapsulated FTZ at a concentration of 2.0 mg FTZ kg−1 soil. Soil degradation experiments suggested that the microcapsules worked effectively to protect the FTZ from degradation, which resulted in higher efficacy at a later stage. A simulation study to predict the concentration of FTZ outside the microcapsule found that the timing of supplying FTZ was important and suggested that the mixture of non‐encapsulated FTZ (non‐MC) and MF‐MC showed enhanced efficiency for the entire cultivation period in the biological test; the efficacy against nematodes was also confirmed by the measurement of nematode density using the Bearman funnel method. CONCLUSION: The release properties of FTZ from microcapsules are critical for their effective application against M. incognita, and the established simulation study is a useful step in designing suitable release properties under complex soil conditions. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Objective. This study was performed to expose nematodes of the Anisakidae family to different aqueous extracts and identify those extracts with nematicidal capacity. Material and methods. The concentrations of bioactive compounds in the aqueous extracts of epazote (Dysphania ambrosioides), onion (Allium cepa), siempre viva (Kalanchoe pinnata), and xoconostle (Opuntia oligacantha) were identified. Live parasites of the Anisakidae family were obtained from Lisa fish (Mugilidae) and exposed to different concentrations of these extracts. Results. K. pinnata and O. oligacantha exhibited higher concentrations of bioactive compounds, including polyphenols, flavonoids, and tannins, as well as greater antioxidant activity in DPPH and ABTS assays. The parasite mortality rate was 100% at 48 hours with a concentration of 855 mg/mL of K. pinnata. For O. oligacantha, the pulp and whole fruit extracts caused 66% mortality at 72 hours. The main histopathological changes induced by K. pinnata were muscle vacuoles. In O. oligacantha, the whole fruit caused degeneration and vacuolization of the intestinal epithelium, while the seed extract caused edema, intestinal degeneration, and vacuolization. Conclusions. These results suggest that aqueous extracts of K. pinnata and O. oligacantha are effective nematicidal agents against nematodes of the Anisakidae family. [ABSTRACT FROM AUTHOR]

Southern root-knot nematodes are among the most pernicious phytoparasites; they are responsible for substantial yield losses in agricultural crops worldwide. The limited availability of nematicides for the prevention and control of plant-parasitic nematodes necessitates the urgent development of novel nematicides. Natural products have always been a key source for the discovery of pesticides. Waltherione A, an alkaloid, exhibits potent nematocidal activity. In this study, we designed and synthesized a series of quinoline and quinolone derivatives from Waltherione A, leveraging a strategy of structural simplification. Bioassays have revealed that the quinoline derivatives exhibit better activity than quinolone derivatives in terms of both nematocidal and fungicidal activities. Notably, compound D1 demonstrated strong nematocidal activity, with a 72 h LC50 of 23.06 μg/mL, and it effectively controlled the infection of root-knot nematodes on cucumbers. The structure–activity relationship suggests that the quinoline moiety is essential for the nematocidal efficacy of Waltherione A. Additionally, compound D1 exhibited broad-spectrum fungicidal activity, with an EC50 of 2.98 μg/mL against Botrytis cinerea. At a concentration of 200 μg/mL, it significantly inhibited the occurrence of B. cinerea on tomato fruits, with an inhibitory effect of 96.65%, which is slightly better than the positive control (90.30%). [ABSTRACT FROM AUTHOR]

Fluopyram, a pyridyl ethyl benzamide broad-spectrum fungicide and nematicide, used for the management of plant parasitic nematodes and soil-borne fungi, is recommended for use in crops like tomato, potato and tobacco. Fluopyram being a pesticide used for drenching soil, there is every possibility of it getting leached down with water, ultimately leading to contamination of waterbodies. An experiment was conducted to study the downward movement of fluopyram in laterite and red loam soils in Kerala, India. Fluopyram and fluopyram benzamide, each at150 µg, were loaded separately on top of the respective soil column and were eluted separately with 20, 40, 80 and 160 mL each of water equivalent to 50, 100, 200 and 400 mm rainfall. It was observed that 76.84% and 74.85% of fluopyram and 73.48% and 64.24% of fluopyram benzamide were confined to the top 0–10 cm soil with application of 20 mL water in laterite and red loam soil, respectively. More than 50% of fluopyram and fluopyram benzamide were detected in the top 0–10 cm layer of soil with the application of 40 and 80 mL water. With the application of 160 mL water, considerable reduction in the concentration of both compounds was observed and the residues moved beyond 30 cm. Leaching of residues was more in laterite soil than in red loam soil, and they are in direct relation to the volume of water applied and the residues moved beyond 30 cm depth with 160 mL water. [ABSTRACT FROM AUTHOR]

Building upon prior research demonstrating the excellent antifungal and nematicidal efficacy of Annona squamosa Lin. seed extracts, this study extends its scope to investigate similar properties in seed extracts from two other Annonaceae species: Annona muricata Lin. and Annona glabra Lin. The focus is on assessing their effectiveness against tomato late blight (TLB) and wheat leaf rust (WLR) diseases, as well as their broader antifungal activity against Colletotrichum sp. and Fusarium sp. The A. glabra seed extract exerted a superior control efficacy against TLB (85 % at 62.5 μg/mL) and WLR (75 % at 125 μg/mL) in vivo. The two Annonaceous extracts also exhibited in vitro antifungal inhibition against Colletotrichum sp. and Fusarium sp., as well as toxicology against pine wilt nematodes and Artemia salina. Besides, they showed phytotoxicity against Raphanus sativus seed germination. Squamocin G, a potent bioactive acetogenin, was isolated from A. glabara, which was found to occur at high contents in the following ascending order in A. glabra, A. muricata and A. squamosa dichloromethane extracts. To investigate the antifungal mechanism, molecular docking and molecular dynamic of squamocin G ligand were also performed for the first time at the active site of succinate dehydrogenase and β‐tubulin. [ABSTRACT FROM AUTHOR]

Plant parasitic nematodes (PPNs) pose a significant threat to global crop productivity, causing an estimated annual loss of US $157 billion in the agriculture industry. While synthetic chemical nematicides can effectively control PPNs, their overuse has detrimental effects on human health and the environment. Biocontrol agents (BCAs), such as bacteria and fungi in the rhizosphere, are safe and promising alternatives for PPNs control. These BCAs interact with plant roots and produce extracellular enzymes, secondary metabolites, toxins, and volatile organic compounds (VOCs) to suppress nematodes. Plant root exudates also play a crucial role in attracting beneficial microbes toward infested roots. The complex interaction between plants and microbes in the rhizosphere against PPNs is mostly untapped which opens new avenues for discovering novel nematicides through multi-omics techniques. Advanced omics approaches, including metagenomics, transcriptomics, proteomics, and metabolomics, have led to the discovery of nematicidal compounds. This review summarizes the status of bacterial and fungal biocontrol strategies and their mechanisms for PPNs control. The importance of omics-based approaches for the exploration of novel nematicides and future directions in the biocontrol of PPNs are also addressed. The review highlighted the potential significance of multi-omics techniques in biocontrol of PPNs to ensure sustainable agriculture. [ABSTRACT FROM AUTHOR]

The sustainable management of large amounts of fly ash (FA) is a concern for researchers, and we aim to determine the FA application in plant development and nematicidal activity in the current study. A pot study is therefore performed to assess the effects of adding different, FA-concentrations to soil (w/w) on the infection of chickpea plants with the root-knot nematode Meloidogyne incognita. Sequence characteristic amplified region (SCAR) and internal transcribed spacer (ITS) region-based-markers were used to molecularly confirm M. incognita. With better plant growth and chickpea yield performance, FA enhanced the nutritious components of the soil. When compared with untreated, uninoculated control (UUC) plants, the inoculation of M. incognita dramatically reduced chickpea plant growth, yield biomass, and metabolism. The findings showed that the potential of FA to lessen the root-knot nematode illness in respect of galls, egg-masses, and reproductive attributes may be used to explain the mitigating effect of FA. Fascinatingly, compared with the untreated, inoculated control (UIC) plants, the FA treatment, primarily at 20%, considerably (p ≤ 0.05) boosted plant growth, yield biomass, and pigment content. Additionally, when the amounts of FA rose, the activity of antioxidants like superoxide dismutase-SOD, catalase-CAT, and peroxidase-POX as well as osmo-protectants like proline gradually increased. Therefore, our findings imply that 20% FA can be successfully applied as a potential strategy to increase biomass yield and plant growth while simultaneously reducing M. incognita infection in chickpea plants. [ABSTRACT FROM AUTHOR]

• MgONPs were synthesized through green approach using trichoderma fungus. • Myco-synthesized NPs exhibited strong nematicidal activity. • Soil application of NPs improved plant growth under nematode infection. • Soil application of NPs reduced nematode population and development. Meloidogyne incognita is believed to be the most devastating pest causing severe damage to crops, and hence, innovative and effective means of controlling the nematode is the need of the day. The focus of the current study is to devise an effective and innovative myco-fabrication of MgO nanoparticles (NPs) along with melatonin for efficient management of M. incognita infecting tomatoes. Fungal extracts were used to synthesize the myco-fabricated NPs through a green synthesis pathway and were verified using different spectroscopic means. The nanoparticles exhibited appreciable nematicidal potential, such as drastic egg hatch inhibition and juvenile mortality under in vitro assays. Evaluation of NPs and melatonin in planta, alone or combined form, was investigated on tomato plants already inoculated with M. incognita. The alterations in the nematode population on roots of plants as well as in soil, growth parameters, and biochemical attributes of plants were recorded. A significant reduction in nematode population was revealed on the application of melatonin and myco-fabricated nanoparticles, hence exhibiting an improvement in the plant's biochemical (glutathione, phenolic, flavonoid, and antioxidant enzymes) and growth parameters. A synergistic impact was shown on the combined application of the treatments. Furthermore, an enhancement in the expression as well as activities of antioxidant enzymes was also observed. Increased resistance of plants against nematodes resulted in connection with the improved antioxidant status of plants due to this combined treatment. The significantly improved growth of plants under M. incognita stress conditions reveals the potential of the proposed treatments having synergistic interaction to manage phyto-parasitic nematodes effectively. This presents innovative means of agricultural biotechnologies that have the potential to contribute to the efficient management of nematodes infecting plants. [ABSTRACT FROM AUTHOR]

Summary: Brassica plants naturally produce glucosinolates as secondary metabolites hydrolysed to biocidal isothiocyanates (ITCs). As such, they have the potential for nematode management through a strategy known as biofumigation. Pratylenchus penetrans causes significant yield losses in many important crops. Understanding the relative impact of different ITCs on the motility and mortality of this nematode species could provide some insights into the selection of relevant brassica biofumigants. The effects of 3.125, 6.25, 12.5, 25, and 50 μ g ml−1 of pure Allyl, 2-Phenylethyl and Benzyl ITCs on the motility and mortality of P. penetrans were evaluated in laboratory in vitro assays. Motility was assessed after incubating the nematodes in ITCs for 24, 48 and 72 h with distilled water as a negative control. Motile and non-motile nematodes were counted. After motility assessment at 72 h, nematodes were rinsed and incubated in water for 48 h, after which live and dead nematodes were counted. Nematodes were considered dead if they remained non-motile after probing with a picking needle. Nematode motility and mortality were significantly affected by the type of ITC, concentration and time of exposure. The number of non-motile nematodes increased with increasing concentration and time of exposure across all tested ITCs. The ED50 values (concentration required to cause 50% non-motility) of Allyl, 2-Phenylethyl and Benzyl were 37.4, 12.8 and 8.6 μ g ml−1 after 24 h exposure. The ITC with potentially the greatest nematicidal effect was Benzyl (LD50 = 3.2 μ g ml−1), followed by 2-Phenylethyl (LD50 = 5.2 μ g ml−1), and Allyl (LD50 = 9.9 μ g ml−1). The LD50 of all ITCs were not different from the ED50 after 72 h, meaning the effects of ITCs could be considered irreversible. This study suggests that brassica biofumigants that produce Benzyl, Allyl and 2-Phenylethyl ITCs are promising candidates for biofumigation of P. penetrans. [ABSTRACT FROM AUTHOR]

Climatic changes and global warming affect the growth, development, and productivity of crops. In this review, we highlight the possible benefits of using innovative breeding techniques like clustered regularly interspaced short palindromic repeats (CRISPRs), exogenous phytohormone-like strigolactones (SLs), nanomaterials (NMs), and beneficial microbial endophytes to address the challenges in sustainable cultivation of horticultural crops. These applications are evaluated by examining how they affect different metabolic, morphological, and biochemical parameters in diverse crops. Endophytes are symbiotic microorganisms and can be used as nematicides for improving crop yield. With an emphasis on quality control, we examined the impacts of applying NMs, a novel family of phytohormones called SLs, and microbial endophytes on horticultural commodities. Furthermore, we reviewed the benefits of CRISPR for the editing of plant genomes, as well as how it affects gene expression and transcription factors to increase crop tolerance and yield. These innovations hold the potential to improve crop yield, quality, and resilience by acting as safe, natural components in biofertilizers and plant protection solutions. Gradually adopting these methods could decrease reliance on agrochemicals, thereby reducing their negative effects on biodiversity, soil fertility, and human health. [ABSTRACT FROM AUTHOR]

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Plant-parasitic nematodes are a major problem for horticultural production, causing significant economic losses. Chemical nematicides are a common nematode control strategy but can negatively impact the environment and human health. In this review, we provide an overview of the use of fungi for the biological control of plant-parasitic nematodes in horticultural crops. Fungal bio-control represents an alternative, environmentally friendly strategy for managing nematodes. The use of fungi for the bio-control of nematodes has gained increasing attention due to the potential benefits of selectivity, sustainability, and long-term control. Here, we discuss the different types of fungi used for nematode management, the mechanisms of their action, the advantages and limitations of using fungi for bio-control, and the factors affecting their efficacy. Additionally, we provide several case studies of fungal bio-control against root-knot, cyst, and lesion nematodes in horticultural crops. The review concludes with a discussion of future directions and research recommendations for implementing fungal bio-control in horticultural crops. [ABSTRACT FROM AUTHOR]

Background and aims: Root-knot nematodes (RKN; Meloidogyne spp.) are among the highly prevalent and significantly detrimental pathogens that cause severe economic and yield losses in crops. Currently, control of RKN primarily relies on the application of chemical nematicides but it has environmental and public health concerns, which open new doors for alternative methods in the form of biological control. Methods: In this study, we investigated the nematicidal and attractive activities of an endophytic strain WF01 against Meloidogyne incognita in concentration-dependent experiments. The active nematicidal metabolite was extracted in the WF01 crude extract through the Sephadex column, and its structure was identified by nuclear magnetic resonance and mass spectrometry data. Results: The strain WF01 was identified as Aspergillus tubingensis based on morphological and molecular characteristics. The nematicidal and attractive metabolite of A. tubingensis WF01 was identified as oxalic acid (OA), which showed solid nematicidal activity against M. incognita, having LC50 of 27.48 μg ml–1. The Nsy-1 of AWC and Odr-7 of AWA were the primary neuron genes for Caenorhabditis elegans to detect OA. Under greenhouse, WF01 broth and 200 μg ml–1 OA could effectively suppress the disease caused by M. incognita on tomatoes respectively with control efficiency (CE) of 62.5% and 70.83%, and promote plant growth. In the field, WF01-WP and 8% OA-WP formulations showed moderate CEs of 51.25%–61.47% against RKN in tomato and tobacco. The combined application of WF01 and OA resulted in excellent CEs of 66.83% and 69.34% toward RKN in tomato and tobacco, respectively. Furthermore, the application of WF01 broth or OA significantly suppressed the infection of J2s in tomatoes by upregulating the expression levels of the genes (PAL, C4H, HCT, and F5H) related to lignin synthesis, and strengthened root lignification. Conclusion: Altogether, our results demonstrated that A. tubingensis WF01 exhibited multiple weapons to control RKN mediated by producing OA to lure and kill RKN in a concentration-dependent manner and strengthen root lignification. This fungus could serve as an environmental bio-nematicide for managing the diseases caused by RKN. [ABSTRACT FROM AUTHOR]

Considering the stricter European regulations for chemical pesticides (e.g. abolishment of the use of chemical soil fumigation products, such as methyl bromide), the need for more sustainable plant protection products is strongly increasing. In this research, Product X, an innovative mixture of bio-nematicidal compounds was developed and evaluated for efficacy. Product X showed a direct nematicidal effect against the root-knot nematode Meloidogyne incognita. In pot trials with tomato plants infected with M. incognita, Product X treatment lead to a significant reduction in nematode-induced gall formation. mRNA-sequencing indicated alterations in phytohormone levels and ROSmetabolism in tomato roots upon treatment with Product X, which was subsequently biochemically validated. Increased levels of abscisic acid and peroxidase activity seem to be the main factors in the response of tomato plants to Product X. Long-term administration of Product X did not yield negative effects on tomato growth or yield. In conclusion, Product X provides a new interesting mix of bio-active compounds in the combat against rootknot nematodes. [ABSTRACT FROM AUTHOR]

Root-knot nematodes (RKNs) are a vital pest that causes significant yield losses and economic damage to potato plants. The use of chemical pesticides to control these nematodes has led to environmental concerns and the development of resistance in the nematode populations. Endophytic fungi offer an eco-friendly alternative to control these pests and produce secondary metabolites that have nematicidal activity against RKNs. The objective of this study is to assess the efficacy of Aspergillus flavus (ON146363), an entophyte fungus isolated from Trigonella foenum-graecum seeds, against Meloidogyne incognita in filtered culture broth using GC–MS analysis. Among them, various nematicidal secondary metabolites were produced: Gadoleic acid, Oleic acid di-ethanolamide, Oleic acid, and Palmitic acid. In addition, biochemical compounds such as Gallic acid, Catechin, Protocatechuic acid, Esculatin, Vanillic acid, Pyrocatechol, Coumarine, Cinnamic acid, 4, 3-indol butyl acetic acid and Naphthyl acetic acid by HPLC. The fungus was identified through morphological and molecular analysis, including ITS 1–4 regions of ribosomal DNA. In vitro experiments showed that culture filtrate of A. flavus had a variable effect on reducing the number of egg hatchings and larval mortality, with higher concentrations showing greater efficacy than Abamectin. The fungus inhibited the development and multiplication of M. incognita in potato plants, reducing the number of galls and eggs by 90% and 89%, respectively. A. flavus increased the activity of defense-related enzymes Chitinas, Catalyse, and Peroxidase after 15, 45, and 60 days. Leaching of the concentrated culture significantly reduced the second juveniles' stage to 97% /250 g soil and decreased the penetration of nematodes into the roots. A. flavus cultural filtrates via soil spraying improved seedling growth and reduced nematode propagation, resulting in systemic resistance to nematode infection. Therefore, A. flavus can be an effective biological control agent for root-knot nematodes in potato plants. This approach provides a sustainable solution for farmers and minimizes the environmental impact. [ABSTRACT FROM AUTHOR]

In the present work, laboratory assays were performed to appraise the biocontrol potential of Metarhabditis amsactae, a Rhabditid nematode, against fifth instar larvae of Corcyra cephalonica. Virulence was tested at four different doses, i.e. 20, 40, 80 and 160 IJs/L (infective juveniles per larva) and mortality was documented from 24 up to 96 h of nematode treatment. Concentration and time-based enhancement in larval mortality was observed with 100% mortality recorded at 160 IJs/L after 96 h. Even at 20 IJs/L concentration, 60% and 76.7% larval mortality was recorded after 72 and 96 h, respectively. At 80 IJs/L, the mortality increased from 33.3% at 48 h to more than 90% at 96 h of nematode inoculation. Whereas, at 40 IJs/L, it enhanced from 16.7% at 48 h to 83.3% at 96 h. The effect of M. amsactae infection on the immune system of C. cephalonica was also evaluated at a dose of 100 IJs/L after 12, 24, 36 and 48 h time intervals. Insect larvae displayed augmented levels of antioxidant and detoxifying enzymes. The peak activities of superoxide dismutase, catalase, ascorbate peroxidase, phenol oxidase and glutathione-S-transferase in infected larvae were observed after 36 h, whereas acetylcholine esterase levels peaked after 48 h, as compared to control. Malondialdehyde content was also increased post nematode infection. Thus the current study is the first report that depicts the significant bioefficacy and immunomodulatory effects of M. amsactae against C. cephalonica under laboratory conditions. However, further research to assess its efficiency under field conditions is required. [ABSTRACT FROM AUTHOR]

Left unchecked, plant-parasitic nematodes have the potential to devastate crops globally. Highly effective but non-selective nematicides are justifiably being phased-out, leaving farmers with limited options for managing nematode infestation. Here, we report our discovery of a 1,3,4-oxadiazole thioether scaffold called Cyprocide that selectively kills nematodes including diverse species of plant-parasitic nematodes. Cyprocide is bioactivated into a lethal reactive electrophilic metabolite by specific nematode cytochrome P450 enzymes. Cyprocide fails to kill organisms beyond nematodes, suggesting that the targeted lethality of this pro-nematicide derives from P450 substrate selectivity. Our findings demonstrate that Cyprocide is a selective nematicidal scaffold with broad-spectrum activity that holds the potential to help safeguard our global food supply. Plant-parasitic nematodes have the potential to destroy crops globally, and limited options for managing nematode infestation are available. Here, the authors report the 1,3,4-oxadiazole thioether scaffold called Cyprocide that selectively kills nematodes including diverse species of plant-parasitic nematodes. [ABSTRACT FROM AUTHOR]

Zinc oxide nanoparticles (ZnO NPs) exhibit diverse applications, including antimicrobial, UV-blocking, and catalytic properties, due to their unique structure and properties. This study focused on the characterization of zinc oxide nanoparticles (ZnO NPs) synthesized from Juglans regia leaves and their application in mitigating the impact of simultaneous infection by Meloidogyne arenaria (root-knot nematode) and Macrophomina phaseolina (root-rot fungus) in cowpea plants. The characterization of ZnO NPs was carried out through various analytical techniques, including UV–visible spectrophotometry, Powder-XRD analysis, FT-IR spectroscopy, and SEM-EDX analysis. The study confirmed the successful synthesis of ZnO NPs with a hexagonal wurtzite structure and exceptional purity. Under in vitro conditions, ZnO NPs exhibited significant nematicidal and antifungal activities. The mortality of M. arenaria juveniles increased with rising ZnO NP concentrations, and a similar trend was observed in the inhibition of M. phaseolina mycelial growth. SEM studies revealed physical damage to nematodes and structural distortions in fungal hyphae due to ZnO NP treatment. In infected cowpea plants, ZnO NPs significantly improved plant growth parameters, including plant length, fresh mass, and dry mass, especially at higher concentrations. Leghemoglobin content and the number of root nodules also increased after ZnO NP treatment. Additionally, ZnO NPs reduced gall formation and egg mass production by M. arenaria nematodes and effectively inhibited the growth of M. phaseolina in the roots. Furthermore, histochemical analyses demonstrated a reduction in oxidative stress, as indicated by decreased levels of reactive oxygen species (ROS) and lipid peroxidation in ZnO NP-treated plants. These findings highlight the potential of green-synthesized ZnO NPs as an eco-friendly and effective solution to manage disease complex in cowpea caused by simultaneous nematode and fungal infections. [ABSTRACT FROM AUTHOR]

Melon (Cucumis melo L.) is a globally grown crop renowned for its juice and flavor. Despite growth in production, the melon industry faces several challenges owing to a wide range of biotic and abiotic stresses throughout the growth and development of melon. The aim of the review article is to consolidate current knowledge on the genetic mechanism of both biotic and abiotic stress in melon, facilitating the development of robust, disease-resistant melon varieties. A comprehensive literature review was performed, focusing on recent genetic and molecular advancements related to biotic and abiotic stress responses in melons. The review emphasizes the identification and analysis of quantitative trait loci (QTLs), functional genes, and molecular markers in two sections. The initial section provides a comprehensive summary of the QTLs and major and minor functional genes, and the establishment of molecular markers associated with biotic (viral, bacterial, and fungal pathogens, and nematodes) and abiotic stress (cold/chilling, drought, salt, and toxic compounds). The latter section briefly outlines the molecular markers employed to facilitate marker-assisted backcrossing (MABC) and identify cultivars resistant to biotic and abiotic stressors, emphasizing their relevance in strategic marker-assisted melon breeding. These insights could guide the incorporation of specific traits, culminating in developing novel varieties, equipped to withstand diseases and environmental stresses by targeted breeding, that meet both consumer preferences and the needs of melon breeders. [ABSTRACT FROM AUTHOR]

Background: Plant-parasitic root-knot nematode (Meloidogyne incognita) causes global yield loss in agri- and horticultural crops. Nematode management options rely on chemical method. However, only a handful of nematicides are commercially available. Resistance breeding efforts are not sustainable because R gene sources are limited and nematodes have developed resistance-breaking populations against the commercially available Mi-1.2 gene-expressing tomatoes. RNAi crops that manage nematode infection are yet to be commercialized because of the regulatory hurdles associated with transgenic crops. The deployment of the CRISPR/Cas9 system to improve nematode tolerance (by knocking out the susceptibility factors) in plants has emerged as a feasible alternative lately. Results: In the present study, a M. incognita-responsive susceptibility (S) gene, amino acid permease (AAP6), was characterized from the model plant Arabidodpsis thaliana by generating the AtAAP6 overexpression line, followed by performing the GUS reporter assay by fusing the promoter of AtAAP6 with the β-glucuronidase (GUS) gene. Upon challenge inoculation with M. incognita, overexpression lines supported greater nematode multiplication, and AtAAP6 expression was inducible to the early stage of nematode infection. Next, using CRISPR/Cas9, AtAAP6 was selectively knocked out without incurring any growth penalty in the host plant. The 'Cas9-free' homozygous T3 line was challenge inoculated with M. incognita, and CRISPR-edited A. thaliana plants exhibited considerably reduced susceptibility to nematode infection compared to the non-edited plants. Additionally, host defense response genes were unaltered between edited and non-edited plants, implicating the direct role of AtAAP6 towards nematode susceptibility. Conclusion: The present findings enrich the existing literature on CRISPR/Cas9 research in plant-nematode interactions, which is quite limited currently while compared with the other plant-pathogen interaction systems. [ABSTRACT FROM AUTHOR]

Background: The role of soil solarization in suppression of soil borne pathogens and weeds has been established by several researchers around the globe It involves capturing solar radiations when the soil receives the maximum sunlight in May-June using a polythene mulch. Its effectiveness depends on ambient temperature, duration of the treatments and soil moisture. This not only acts as a soil disinfectant but also as soil decontamination. It includes various changes in the soil like physical, chemical and biological properties. Methods: The field to lab and vice-versal based investigations were carried during 2021-2022 at Amity Centre for Biocontrol and Plant Disease Management, Amity University, Uttar Pradesh, Noida and identified tomato nurseries of district G B Nagar where heavy infestation (10-12 J2/cc soil) of root knot nematode, Meloidogyne incognita (Kofoid and White) Chitwood was recorded. The treatments comprised of sustainable components viz. deoiled seed cake of neem, a Arbuscular Mycorrhizal fungus Glomus intraradices and indigenous fungal strain of Trichoderma harzianum, (Th7) alone and together applied for evolving IPM module at solarized and unsolarized sets. Under microplot trials, the entire solarized treatments were carried out measuring 3 x 1 sq. meter each in which one set of all the treatments including control covered with clear transparent polythene sheet (400 µ gauge) for solarization. The treatments were replicated thrice in randomized block design. Result: The observations of solarized and unsolarized treatments clearly revealed that the soil solarization in treatments where the sun radiant energy was trapped by 400 µ transparent polysheets significantly reduced the root knot nematode Meloidogyne incognita population both in root and soil in comparison to unsolarized treatments where no solar energy trapping was done. The combined application of locally isolated Trichoderma harzianum (Th7) and VA mycorrhiza, Glomus intraredices enhanced germination and plant growth in nurseries. In the present investigation, the solarized IPM module-4 comprising of other sustainable components viz. neem oil-seed cake, T. harzianum (Th-7) and Arbuscular Mycorrhizal (AM) fungus G. intraredices is proved to be an ideal one in rootknot nematode pest management in tomato nurseries. [ABSTRACT FROM AUTHOR]

Zinc (Zn) and copper (Cu) are common contaminants of inland water bodies under severe anthropogenic pressure. The main aim of this study was to test the influence of environmental aqueous concentrations of Zn and Cu on the fitness-related life history traits of the cosmopolitan freshwater ostracod Heterocypris incongruens. Overall, eight subchronic laboratory experiments were conducted to test the effects of exposure to two Cu (260 and 460 µg Cu L−1) and Zn (230 and 410 µg Zn L−1) concentrations compared to the control conditions using asexual individuals originating from a wild population and from a commercial toxicity test (Ostracodtoxkit f). The response of ostracods to exposure to Zn and Cu differed considerably. The Cu treatments significantly reduced the total hatching success and hatching dynamics of resting eggs, increased the mortality of juveniles and reduced the survival of adults, dramatically decreasing the fitness of ostracods. On the other hand, the Zn treatments were less harmful and did not affect adult survival or the timing of juvenile hatching from subitaneous eggs but extended the timing of laying eggs at lower concentrations and stimulated hatching dynamics and success at higher concentrations. It seems that the increased Zn body burden did not strongly impact the fitness of the studied specimens. Moreover, the different responses of the laboratory and wild populations in the Zn experiments may suggest a genetic variation in the tolerance of ostracods to metals. Therefore, experiments involving laboratory H. incongruens as analogues of wild ostracods should be cautiously interpreted. We concluded that the major toxicant in our study was Cu, while Zn could be considered a micronutrient even supporting ostracod fitness, although its higher levels are likely to exert strong toxic effects. [ABSTRACT FROM AUTHOR]

Entomopathogenic nematodes (EPNs) are biocontrol agents against various insect pests in the world for their characteristics of infectivity and compatibility with different control agents. Several environmental factors directly affect the EPN populations in the soil, as well as the resistance of certain insect pests to EPN penetration. Under these circumstances, EPNs cannot exhibit high virulence on the targeted insect pest; therefore, they should be applied in combination with some of the other control agents. In this context, the main objective of this review was to summarize the current knowledge on the compatibility of EPNs with various agrochemicals and examine the interactions of EPNs and these agents in combined application against insect pests. This review highlighted firstly the growing research attention worldwide concerning the compatibility of EPNs with other control agents. Then, the compatibility of EPNs with synthetic insecticides of different classes was reviewed. In this regard, also, some special attention has been paid to herbicides, fungicides and nematicidal compounds as possible compatible agents to EPNs. Later on, the current review discussed the importance of EPN application in combination with different insect growth regulators, juvenoids, ecdysteroids and chitin synthesis inhibitors. An overview of agricultural management practices and soil amendments in relation to EPNs was provided including the compatibility of EPNs with organic and inorganic fertilizers. Some attention has been paid to the EPN tolerance and susceptibility to heavy metals and other soil chemical pollutants, and EPNs as good bio-indicators of the environmental pollutants. The last aspect was the compatibility of EPNs with crude plant extracts and isolated phytochemicals. In conclusion, a combination of EPNs with compatible agrochemicals is a promising approach to the pest control strategy. EPNs may be combined with various compatible agrochemicals with additive, or preferably synergistic, effects on pest mortality. For this purpose, also, the exposure period should also be taken into consideration, because the exposure of EPNs to agrochemicals for a prolonged exposure period may turn their interaction to antagonistic and subsequently low control efficiency against the targeted insect due to the reduction of the EPN viability and infectivity. [ABSTRACT FROM AUTHOR]

De novo drug design focused on in silico research of more effective and safe drugs is the essential stage of pharmacophore-based drug discovery. This study aimed to evaluate the anthelmintic potential of herbal ligand derivatives to suggest new drug scaffolds and examine fragment-based key-lock fit models of drug candidates to offer more potent drugs. The reversible inhibitors of the Carnitine Palmitoyltransferase 2 enzyme (CPT 2) have been evaluated as anthelmintic drug candidates because the increased CPT 2 substrate in the environment leads to the death of the nematode. Eriocitrin is a herbal molecule found in several plants, especially in the citrus peel. It has never been previously investigated for anthelmintic purposes, but it is a molecule found in some anthelmintic plants. Therefore, eriocitrin was determined as the scaffold of a novel anthelmintic drug candidate. To design new eriocitrin derivatives, positions 3 and 8 on the chromene ring of eriocitrin were chosen to insert five different side groups, such as hydrogen, propylsulfanyl, acetate, phenol, and aniline. Twenty-four derivatives designed with Biovia Discovery Studio 2020 Client were docked with the antinematodal drug target rat CPT 2 using AutoDock4.2 software. ADME properties and the binding mode of the most potent derivative were investigated. For the derivative with the best-scored molecule E05, the free binding energy was -9.08 kcal/mol, and the Ki value was calculated as 22.017 nM. E05, which had a better inhibition value than eriocitrin showed that the presence of phenol at the 3rd position in the chromene nucleus of eriocitrin facilitated CPT 2 inhibition. This research is the first study that shows the eriocitrin and E05 are potent anthelmintic molecules according to in silico docking tests. E05 is worth to be investigated comprehensively with further in vitro studies. [ABSTRACT FROM AUTHOR]

Citrus microcarpa is a popular nutritious fruit that is widely cultivated in China. In recent years, many compounds with significant pharmacological activities have been isolated successfully from the pericarp of C. microcarpa. However, to date, there are no reports on the activity of C. microcarpa pericarp against root-knot nematodes. This study used the ethanolic extract from the pericarp of Hainan C. microcarpa and the impregnation method to determine its activity on J2 Meloidogyne enterolobii specimens and on single-egg hatching. The results showed that when J2 individuals were treated with 50 mg.L-1 of the extract, the lethal concentration 50 values after 24 and 48 hours were 17.124 and 8.858 mg-mL-1, respectively. The mortality rate of nematodes after 48 hours of treatment was 100%, and the inhibition rate of single-egg hatching after 24 hours was 89.29%. The ethanolic extract of C. microcarpa peels showed high inhibitory and lethal activity against the M. enterolobii. The analysis of the chemical composition of the extract revealed 28 substances with insecticidal and antibacterial effects, including lignans, flavonoids, fatty acids, organic acids, terpenoids, and imidazole. The formulas of the chemical structures and pharmacological effects of these potential insecticidal and antibacterial substances were elucidated to provide a scientific basis and a theoretical reference for the use of C. microcarpa pericarps as a raw material for the development of new, natural plant nematicides. [ABSTRACT FROM AUTHOR]

Claviceptaceous endophytic fungi in the genus Epichloë mostly form a symbiotic relationship with cool-season grasses. Epichloë spp. are capable of producing bioactive alkaloids such as peramines, lolines, ergot alkaloids, and indole-diterpenes, which protect the host plant from herbivory by animals, insects, and nematodes. The host also benefits from enhanced tolerance to abiotic stresses, such as salt, drought, waterlogging, cold, heavy metals, and low nitrogen stress. The bioactive alkaloids produced can have both direct and indirect effects towards plant parasitic nematodes. Direct interaction with nematodes' motile stages can cause paralysis (nematostatic effect) or death (nematicidal effect). Indirectly, the metabolites may induce host immunity which inhibits feeding and subsequent nematode development. This review highlights the different mechanisms through which this interaction and the metabolites produced have been explored in the suppression of plant parasitic nematodes and also how the specific interactions between different grass genotypes and endophyte strains result in variable suppression of different nematode species. An understanding of the different grass–endophyte interactions and their successes and failures in suppressing various nematode species is essential to enable the proper selection of grass–endophyte combinations to identify the alkaloids produced, concentrations required, and determine which nematodes are sensitive to which specific alkaloids. [ABSTRACT FROM AUTHOR]

Three novel trifluoromethylated compounds were designed and synthesized by reacting trifluoroacetimidoyl chloride derivatives with acetamidine hydrochloride or thiourea in the presence of potassium carbonate or sodium hydrogen carbonate as a base. In vitro and in vivo assays demonstrated the efficacy of the tested compounds in controlling root-knot nematode disease on pistachio rootstocks caused by Meloidogyne incognita. Bis-trifluoromethylated derivatives, namely N,N"-thiocarbonylbis(N'-(3,4-dimethylphenyl)-2,2,2-trifluoroacetimidamide) (compound A1), showed high efficacy as novel and promising nematicides, achieving up to 78.28% control at a concentration of 0.042 mg/liter. This effect is attributed to four methyl and two trifluoromethyl groups. In the pre-inoculation application of compound A1, all three concentrations (0.033, 0.037, and 0.042 mg/liter, and Velum) exhibited a higher level of control, with 83.79, 87.46, and 80.73% control, respectively. In the microplot trials, compound A1 effectively reduced population levels of M. incognita and enhanced plant growth at a concentration of 0.037 mg/liter. This suggests that compound A1 has the potential to inhibit hedgehog protein and could be utilized to prevent the progression of root-knot disease. Furthermore, the molecular docking results revealed that compounds A1 and A3 interact with specific amino acid residues (Gln60, Asp530, Glu70, Arg520, and Thr510) located in the active site of hedgehog protein. Based on the experimental findings of this study, compound A1 shows promise as a lead compound for future investigations. [ABSTRACT FROM AUTHOR]

[Display omitted] • New thiosemicarbazide and 1,2,4-triazole derivatives, not described in the literature, were synthesized. • The anthelmintic activity was tested in vitro and in vivo on four pathogenic nematode species. • The in vivo studies showed no systemic toxicity of the tested compound (II-1). • The degree of inhibition of selected CYP450 enzymes depending on the concentration of the tested compound II-1 was assessed. • The in silico studies indicated tubulin and the SDH enzyme as potential molecular targets of the tested compound (II-1) Intestinal parasitic infections are neglected diseases and, due to the increasing resistance of parasites to available drugs, they pose an increasing therapeutic challenge. Therefore, there is a great need for finding new compounds with antiparasitic activity. Objectives: In this work, new thiosemicarbazide and 1,2,4-triazole derivatives were synthesized and tested for their anthelmintic activity. The synthesis was carried out by classical methods of organic chemistry. Anthelmintic activity tests were carried out in vitro (Rhabditis sp., Haemonchus contortus , Strongylidae sp.) in vivo (Heligmosomoides polygyrus/bakeri), and in silico analysis was performed. Quinoline-6-carboxylic acid derivative compounds were designed and synthesized. The highest activity in the screening tests in the Rhabditis model was demonstrated by compound II-1 with a methoxyphenyl substituent LC 50 = 0.3 mg/mL. In the next stage of the research, compound II-1 was analyzed in the H. contortus model. The results showed that compound II-1 was active and had ovicidal (percentage of dead eggs > 45 %) and larvicidal (percentage of dead larvae > 75 %) properties. Studies in the Strongylidae sp. model confirmed the ovicidal activity of compound II-1 (percentage of dead eggs ≥ 55 %). In vivo studies conducted in the H. polygyrus / bakeri nematode model showed that the number of nematodes decreased by an average of 30 % under the influence of compound II-1. In silico studies have shown two possible modes of action of compound II-1, i.e. inhibition of tubulin polymerization and SDH. The test compound did not show any systemic toxic effects. Its influence on drug metabolism related to the activity of cytochrome CYP450 enzymes was also investigated. The results obtained in the in vitro, in vivo , and in silico studies indicate that the test compound can be described as a HIT, which in the future may be used in the treatment of parasitic diseases in humans and animals. [ABSTRACT FROM AUTHOR]

Nematodes have a negative impact on crop production and yield. The use of synthetic formulations to control plant parasitic nematodes carries both environmental and human health risks. As these agrochemicals are gradually being phased out, recent research has been focused on finding more environmentally friendly, plant-based alternatives. This study aims to investigate the effectiveness of botanicals, used alone or in artificial blends, in paralyzing Meloidogyne incognita second-stage juveniles (J2s) immersed in test solutions or exposed to vapors. We tested thymol, trans-anethole, and two lavender essential oils, referred to as LEOA and LEOB, which vary in their flower and stem compositions. We also employed in our study Melia azedarach aqueous extract (MWE), already proven to have considerable nematicidal activity. According to our findings, all treatments used individually exhibited considerable efficacy, even LEOA and LEOB first reported herein. In addition, all blends exhibited significant synergism, and the best-performing were trans-anethole/thymol, being synergic to paralyzing J2s for up to two days, and trans-anethole/LEOB as well as trans-anethole/MWE, provoking irreversible paralysis since the first day of J2 immersion in test solutions. Most importantly, the blend of trans-anethole with LEOA displayed the best effective synergism against M. incognita both for immersion and fumigation methods. Lastly, the chemical composition analysis displayed linalyl acetate and β-linalool as the major components of LEOA and β-linalool and eucalyptol as the major components of LEOB. [ABSTRACT FROM AUTHOR]

The latest study published in Nature by Andrew R. Burns, Peter J. Roy and co-authors is highlighted in this paper, they investigated a series of novel nematicidal compounds, including Selectivin-A and Selectivin-E, and explored their mechanism of action. Experiments have displayed that the Selectivin compound is inactive to human cells, fish, fungi, insects and even beneficial nematodes. In the exploration of its mechanism of action, it was found that the mechanism of action of Selectivin is different with those of commercial nematocides: Selectivin needs to be activated by biotin produced by nematodes, after that they can be transformed into compounds with high nematicidal activity. This proves that the family of Selectivin compounds has the advantages of high selectivity and environmental friendliness, and their mechanism of action is completely new, proposing a completely new path for the development of new nematicides. [ABSTRACT FROM AUTHOR]

The management of plant-parasitic nematodes (PPNs) still relies on traditional nematicides that threaten the environment and human health. Novel solutions are urgently needed for PPN pest management that are effective while safeguarding non-target organisms. Volatile phytochemicals belong to a structurally diverse group of bioactive metabolites that are believed to hold safer environmental characteristics than synthetic pesticides. Nonetheless, not many studies have analysed the potential environmental benefits of shifting to these novel bionematicides. In the present study, 20 phytochemical volatiles with reported nematicidal activity were compared to traditional pesticides using specific parameters of environmental and human health safety available on applied online databases and predicted in silico through specialised software. Overall, the reviewed nematicidal phytochemicals were reportedly less toxic than synthetic nematicides. They were predicted to disperse to the air and soil environmental compartments and were reported to have a lower toxicity on aquatic organisms. On the contrary, the synthetic nematicides were reportedly toxic to aquatic organisms while showing a predicted high affinity to the water environmental compartment. As alternatives, β-keto or fatty acid derivatives, e.g., aliphatic alcohols or ketones, showed more adequate properties. This study highlights the importance of complementing studies on nematicidal activity with a risk assessment-based analysis to allow for a faster selection of nematicidal phytochemical volatiles and to leverage the development and implementation of bionematicides. [ABSTRACT FROM AUTHOR]

Plant-parasitic nematodes (PPNs) reduce the high profitability of many crops and degrade their quantitative and qualitative yields globally. Traditional nematicides and other nematode control methods are being used against PPNs. However, stakeholders are searching for more sustainable and effective alternatives with limited side effects on the environment and mankind to face increased food demand, unfavorable climate change, and using unhealthy nematicides. This review focuses on upgrading the pre-procedures of PPN control as well as novel measures for their effective and durable management strategies on economically important crops. Sound and effective sampling, extraction, identification, and counting methods of PPNs and their related microorganisms, in addition to perfecting designation of nematode–host susceptibility/resistance, form the bases for these strategies. Therefore, their related frontiers should be expanded to synthesize innovative integrated solutions for these strategies. The latter involve supplanting unsafe nematicides with a new generation of safe and reliable chemical nematicidal and bionematicidal alternatives. For better efficacy, nematicidal materials and techniques should be further developed via computer-aided nematicide design. Bioinformatics devices can reinforce the potential of safe and effective biocontrol agents (BCAs) and their active components. They can delineate the interactions of bionematicides with their targeted PPN species and tackle complex diseases. Also, the functional plan of nematicides based on a blueprint of the intended goals should be further explored. Such goals can currently engage succinate dehydrogenase, acetylcholinesterase, and chitin deacetylase. Nonetheless, other biochemical compounds as novel targets for nematicides should be earnestly sought. Commonly used nematicides should be further tested for synergistic or additive function and be optimized via novel sequential, dual-purpose, and co-application of agricultural inputs, especially in integrated pest management schemes. Future directions and research priorities should address this novelty. Meanwhile, emerging bioactivated nematicides that offer reliability and nematode selectivity should be advanced for their favorable large-scale synthesis. Recent technological means should intervene to prevail over nematicide-related limitations. Nanoencapsulation can challenge production costs, effectiveness, and manufacturing defects of some nematicides. Recent progress in studying molecular plant–nematode interaction mechanisms can be further exploited for novel PPN control given related topics such as interfering RNA techniques, RNA-Seq in BCA development, and targeted genome editing. A few recent materials/techniques for control of PPNs in durable agroecosystems via decision support tools and decision support systems are addressed. The capability and effectiveness of nematicide operation harmony should be optimized via employing proper cooperative mechanisms among all partners. [ABSTRACT FROM AUTHOR]

Introduction: Plant-pathogen interaction is an inexhaustible source of information on how to sustainably control diseases that negatively affect agricultural production. Meloidogyne incognita is a root-knot nematode (RKN), representing a pest for many crops, including tomato (Solanum lycopersicum). RKNs are a global threat to agriculture, especially under climate change, and RNA technologies offer a potential alternative to chemical nematicides. While endogenous microRNAs have been identified in both S. lycopersicum and M. incognita, and their roles have been related to the regulation of developmental changes, no study has investigated the miRNAs cross-kingdom transfer during this interaction. Methods: Here, we propose a bioinformatics pipeline to highlight potential miRNA-dependent cross-kingdom interactions between tomato and M. incognita. Results: The obtained data show that nematode miRNAs putatively targeting tomato genes are mostly related to detrimental effects on plant development and defense. Similarly, tomato miRNAs putatively targeting M. incognita biological processes have negative effects on digestion, mobility, and reproduction. To experimentally test this hypothesis, an in vitro feeding assay was carried out using sly-miRNAs selected from the bioinformatics approach. The results show that two tomato miRNAs (sly-miRNA156a, sly-miR169f) soaked by juvenile larvae (J2s) affected their ability to infect plant roots and form galls. This was also coupled with a significant downregulation of predicted target genes (Minc11367, Minc00111), as revealed by a qRT-PCR analysis. Discussions: Therefore, the current study expands the knowledge related to the cross-kingdom miRNAs involvement in host-parasite interactions and could pave the way for the application of exogenous plant miRNAs as tools to control nematode infection. [ABSTRACT FROM AUTHOR]

Summary: A new genus and species of anguinid nematode, Cotylenchus cleo gen. n., sp. n., was recovered from leaves of the western sword fern, Polystichum munitum , growing in rainforests in several locations of Olympic National Park, Washington State, USA. This new anguinid nematode induced distinct necrotic and chlorotic symptoms on fern leaves characterised by yellowing, light to brown areas between veins. The new species is characterised by a long and slender body, six incisures in the lateral field, robust stylet (12.0-13.5 μ m) with large and rounded knobs, pyriform to elongate and abutting basal pharyngeal bulb, and long conical tail with pointed terminus; females having posteriorly located vulva (V = 74-80%) and well-developed post-vulval uterine sac (26-59 μ m) and males having spicules 20-23 μ m long. Phylogenetic analysis of the partial 18S rRNA and the D2-D3 expansion segments of the 28S rRNA genes showed that this anguinid nematode formed a separate evolutionary lineage different from all other Anguinidae taxa. The new species was also characterised by sequencing the ITS rRNA and COI genes. [ABSTRACT FROM AUTHOR]

Summary: Classical methods of using many toxic chemical pesticides for managing plant-parasitic nematodes (PPN) on key crops are inappropriate and have unfavourable consequences on human health and the environment. By contrast, nanotechnology can provide a wide range of alternative applications with additional merits based on nanoparticle (NP) pesticides. Three major categories, i.e. , physical, chemical and biological methods, have been generally used for synthesis of nanonematicides. The merits and demerits of these methods are highlighted. The biological method generally involves easy, fast, scalable, cheap and environmentally safe techniques. As nanonematicides can reduce the non-selective use of classical nematicides with their high pollution and unhealthy levels, mechanisms underlying PPN population suppression by these nanonematicides are presented to help in their further optimisation. Nanonematicides are guiding a radical change in their efficacy against PPN, but more attention should be given to secure their clean production and application with cost-effective methods. [ABSTRACT FROM AUTHOR]

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Objectives: This study was carried out to investigate the effectiveness of some nanoparticles in inhibiting the growth of the root knot nematode. Methods: This study was carried out to investigate the effectiveness of aluminum oxide Alo-NPs and silver Ag-NPs, and chemical nematicides (Velum prime and Furadan granules), in inhibiting the growth of the root knot nematode (Meloidogyne incognita) on two different types of eggplant cultivars, Barcelona and Thuraya. Results: The result obtained indicated that chemical nematicides and nanoparticles were highly effective in lowering the nematode invasion level expressed as number of knots per root and a gall index based on a 0-5 scale. Velum prime at concentrations of 300 and 400 ppm was the most effective and gave 0.67 and 0.17 knots/root average on both eggplant cultivars, respectively. In addition, the ALO-NPs treatment reduced infection to 1.17 knots/root compared to initial infection of 37.33 knots/root. The use of Ag-NPs at the concentration of 4000 ppm reduced infection to a low average of 2.83 knots/root for both eggplant varieties. All treatments average reduced the gall index to 0.95 (cv. Barcelona) and 1.20 (cv. Thuraya) compared to 3.33 and 4.00 for the infected non-treated controls, respectively. Conclusions: Nanoparticles have a role in controlling root-knot galls as alternatives to chemical pesticides that are dangerous to the environment and humans, and reducing the number of galls on the plant indicates the inhibition of eggs and second stage juveniles (J2). [ABSTRACT FROM AUTHOR]

The nematicidal potential of the yeast Papiliotrema terrestris strain PT22AV (YSY) was investigated against the root nematode (RKN) Meloidogyne incognita in in vitro bioassays on infective juveniles (J2) and experiments on tomatoes in pot and greenhouse conditions. The J2 nematodes were exposed to YSY solutions for 19 days, using abamectin (ABA), fosthiazate (FOS) and distilled water as controls. In the experiments on potted and greenhouse tomatoes, 0.5 and 1 kg ha−1 doses of YSY were tested in comparison to ABA, biocontrol agents Purpureocillium lilacinus strain 251 (PUL) and Bacillus firmus strain 1-1582 (BAF), a plant biostimulant/fertilizer (ERG) and the nematicide Fluopyram (FLU). J2's viability was affected by YSL after 7 days, decreasing to zero on the 15th exposure day, while ABA and FOS resulted in 83 and 100% J2 mortality within 24 h. Only the 1.0 kg ha−1 dose of YSY was able to significantly reduce the final nematode population in soil and gall formation on tomato roots, without significant differences from PUL and BAF. All treatments in comparison also resulted in a significant increase in tomato growth and crop yield, except for 0.5 kg ha−1 of YSY. Data indicated that YSY could represent an additional tool for organic and integrated RKN management. [ABSTRACT FROM AUTHOR]