Nematicidal Activity Research Articles

The nematicidal potential of novel fungus, Trichoderma asperellum FbMi6 against Meloidogyne incognita

One of the most damaging pests in vegetable crops is the root-knot nematode (Meloidogyne incognita) worldwide. The continuous use of nematicide is costly and has unintended consequences for human and environmental health. To minimize nematicides, eco-friendly integrated nematode management is required. Trichoderma, an antagonistic fungus has been explored to control root-knot nematode. The fungal bio-control strain FbMi6 was identified as Trichoderma asperellum (accession no. MT529846.1). T. asperellum FbMi6 showed substantial nematicidal activity in the laboratory, with egg hatch suppression (96.6%) and juvenile mortality (90.3%) of M. incognita. T. asperellum FbMi6 was examined under pot and field conditions (after neem cake enrichment), both alone and in combination, and compared with controls. Application of T. asperellum FbMi6 enriched neem cake (1-ton ha-1) increased (28.3%) the okra yield and decreased (57.1%) nematode population as compared with control. T. asperellum FbMi6 enriched neem cake had higher polyphenol content (resistance enhancer) in okra compared with inoculated check.

Nematicidal and antioxidant activities of the methanolic extract from Tithonia diversifolia grown in Vietnam

Summary This study aimed to evaluate the nematicidal activity of the Tithonia diversifolia leaf extract (TDE) against Meloidogyne incognita under in vitro and pot conditions. In addition, the antioxidant activity of TDE was evaluated using the 2,2-Diphenyl-2-picrylhydrazyl hydrate (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. The results revealed that TDE possesses antioxidant potential. Nematicidal activity bioassays revealed that the TDE treatment resulted in 3.0, 16.3, 36.6, 52.4 and 64.2% second-stage juvenile (J2) hatch inhibition at MeOH control, 0.125, 0.25, 0.5 and 1.0 mg ml−1, respectively, for a 5-day treatment. The corresponding values for a 10-day treatment were 3.3, 16.0, 30.7, 56.0 and 69.3%, respectively. The TDE treatment resulted in 64.6, 86.4, 95.3 and 100% J2 movement inhibition at 0.125, 0.25, 0.5 and 1.0 mg ml−1, respectively, for a 48 h treatment. In pot experiments, at 60 days after treatment (DAT), the J2 populations in non-treated, 0.25, 0.5, 1.0 mg TDE (g soil)−1, and Tervigo 020SC 1.0 mg (g soil)−1 were 477.1, 277.3, 142.7, 23.9 and 19.7 per 5 g of root, respectively. The corresponding values in 100 g of soil were 33.2, 5.5, 3.6, 1.1 and 4.0, respectively. The relative galling formation on the Robusta coffee plants was 100, 55.3, 39.1, 33.5 and 80.8% in the non-treated, 0.25, 0.5, 1.0 mg TDE (g soil)−1, and Tervigo-treated plants, respectively. These results may provide crucial information for exploring the nematicidal metabolites of TDE against M. incognita. Therefore, the purified active compounds of TDE should be identified in future studies before the commercialisation of TDE for the biocontrol of M. incognita.

Industrial assays to evaluate the efficacy of vacuum pressure impregnation with commercial wood preservatives to eliminate the pinewood nematode, Bursaphelenchus xylophilus, and other nematodes from Pinus pinaster wood

To demonstrate the efficacy of the vacuum pressure impregnation (VPI) with commercial wood preservative products to eliminate the quarantine organism, pinewood nematode (PWN), Bursaphelenchus xylophilus, and other nematodes from maritime pine (Pinus pinaster) wood, in vitro assays and industrial assays in horizontal industrial autoclave tanks were conducted. In vitro nematicidal activity assays through direct exposure of the PWN 3rd-stage dispersal juveniles, the resistance juvenile stage, extracted from naturally infected P. pinaster revealed 100% nematode mortality with three commercial wood preservatives. Nematode mortality was also assessed in VPI industrial assays with the three commercial wood preservatives using naturally PWN infected P. pinaster experimental units, with various diameters and sizes. After VPI treatment, the nematode mortality ranged from 99.9761 to 100%. After incubation, the mortality of the total number of nematodes increased and, in all sections, the nematode mortality was higher than 99.9981% and in some it was 100% indicating that wood impregnated with preservative products does not constitute an environment favorable to the reproduction and development of nematodes. Overall, our findings demonstrated that the efficiency of the VPI process results from the joint action of the physical effect of pressure and vacuum and of the nematicidal effect of the preservative product. VPI treatment can be considered a valuable approach to eliminate PWN and other nematodes from maritime pine wood avoiding the subsequent application of the heat treatment.

Volatile Metabolites from Brevundimonas diminuta and Nematicidal Esters Inhibit Meloidogyne javanica.

Brevundimonas diminuta is broadly distributed in terrestrial and aquatic environments and has various biological activities. In this study, we found that B. diminuta exhibited nematicidal activity against the plant root-knot nematode, Meloidogyne javanica. A total of 42 volatile organic compounds (VOCs) from B. diminuta were identified using gas chromatography-mass spectrometry (GC-MS). The nematicidal activity of the 10 main VOCs was tested against M. javanica. Butyl butanoate (4 µL) caused the mortality of 80.13% of M. javanica after 4 h. The nematicidal activity of an additional 38 butyl-butyrate-like volatile esters was also investigated. Of these, seven had strong nematicidal activity against M. javanica, five of which showed egg-hatching inhibitory activity. This study is the first to report that butyl butanoate, ethyl 2-methylbutanoate, ethyl 4-methylpentanoate, ethyl pent-4-enoate, and methyl undecanoate have nematicidal activity against M. javanica. The results indicated that B. diminuta could serve as a candidate microorganism for the biocontrol of plant root-knot nematodes, showing that volatile esters have great potential as nematicides.

Nematicidal activity of Brazilian honeys

In Brazil, there is a great cultural and social diversity, which leads to the use of several natural products due to their ethnopharmacological properties, incluing honey. Honey is a nutrient-rich food that has several beneficial activities, such as: anti-inflammatory, antioxidant, antimicrobial and nematicidal actions. However, there are no studies regarding the nematicidal effect of honeys from Brazil. Thus, the objective of this study was to evaluate the nematicidal action of honeys of Apis mellifera L. from orange, avocado, eucalyptus, multifloral and honey from Tetragonisca angustula species (known as Jataí) on Panagrellus sp. nematodes. In the nematicidal assays, solutions of these honeys were used in concentrations of 3; 1.5; 0.75 and 0.5% (w/v). The control group contained only distilled water. In assays with a concentration of 0.5% of avocado honey and T. angustula bee honey, a significant reduction was demonstrated, compared to the control group (respectively: 41.4% and 47.2%). The results obtained demonstrated, for the first time, that A. mellifera L. honey from avocado flowering and T. angustula honey showed significant nematicidal activity against juveniles of the free-living nematode model Panagrellus sp. Therefore, further studies on the compositions of these honeys must be developed.

Volatile Organic Compounds of Bacillus velezensis GJ-7 against Meloidogyne hapla through Multiple Prevention and Control Modes.

The Bacillus velezensis GJ-7 strain isolated from the rhizosphere soil of Panax notoginseng showed high nematicidal activity and therefore has been considered a biological control agent that could act against the root-knot nematode Meloidogyne hapla. However, little was known about whether the GJ-7 strain could produce volatile organic compounds (VOCs) that were effective in biocontrol against M. hapla. In this study, we evaluated the nematicidal activity of VOCs produced by the fermentation of GJ-7 in three-compartment Petri dishes. The results revealed that the mortality rates of M. hapla J2s were 85% at 24 h and 97.1% at 48 h after treatment with the VOCs produced during GJ-7 fermentation. Subsequently, the VOCs produced by the GJ-7 strain were identified through solid-phase micro-extraction gas chromatography mass spectrometry (SPME-GC/MS). Six characteristic VOCs from the GJ-7 strain fermentation broth were identified, including 3-methyl-1-butanol, 3-methyl-2-pentanone, 5-methyl-2-hexanone, 2-heptanone, 2,5-dimethylpyrazine, and 6-methyl-2-heptanone. The in vitro experimental results from 24-well culture plates showed that the six volatiles had direct-contact nematicidal activity against M. hapla J2s and inhibition activity against egg hatching. In addition, 3-methyl-1-butanol and 2-heptanone showed significant fumigation effects on M. hapla J2s and eggs. Furthermore, all six of the VOCs repelled M. hapla J2 juveniles in 2% water agar Petri plates. The above data suggested that the VOCs of B. velezensis GJ-7 acted against M. hapla through multiple prevention and control modes (including direct-contact nematicidal activity, fumigant activity, and repellent activity), and therefore could be considered as potential biocontrol agents against root-knot nematodes.

Comparative chemical composition and pesticidal evaluation of Acorus calamus accessions collected from different geographical locations

The objectives of the present study were to investigate the phytochemical composition of essential oils (EO) from rhizomes of Acorus calamus collected from Jorhat, Assam; Munsyari and Pantnagar, Uttarakhand, India. EOs were studied for different pesticidal activities viz; nematicidal, insecticidal, and herbicidal activity. To study the synergistic effect of EOs on pesticidal activity, four combinations of EOs were prepared. Phenylpropanoids with β-asarone as the main compound were identified in all collections with varying percentages. Its contribution was found to be 85.8% in Munsyari EOs followed by 74.3% in Pantnagar and 62.6% in Assam collections. All EOs exhibited dose-dependent in vitro nematicidal activity against Meloidogyne incognita in terms of immobility and inhibition of egg hatching. The activity was observed as maximum in the EO combination of all three collections (1:1:1) whereas minimum in the Assam collections. In insecticidal activity against Lipaphis erysimi and Selepa celtis, maximum mortality was observed in Munsyari collections. The oils were assessed for sprout inhibition activity in terms of seed germination inhibition, coleoptile growth of the shoot and root against Raphanus raphanistrum. Maximum seed germination inhibition, % shoot, and root growth inhibition were found in all collections EO combinations. To predict the possible mode of action and the structure-activity relationship between major compounds of EOs and biological activities, in silico molecular docking and ADME/Tox studies were performed. The docking results revealed the mode of action of proteins of insects, nematodes, and weeds and were found in support of in vitro experiments. The study may be helpful for the development of herbal-based pesticides after proper clinical trials.

Phytochemical profile and nematicidal activity of a hydroalcoholic extract from Cazahuate flowers (Ipomoea pauciflora M. Martens & Galeotti) against Haemonchus contortus infective larvae.

Haemonchus contortus (Hc) is a hematophagous parasite affecting the health and productivity of flocks. The administration of chemical anthelmintic drugs (AH) is the common method of deworming; however, generates resistance in the parasites to AH and it is a public health risk due to drug residues in milk, meat and sub-products. Natural compounds from plants are explored to diminish this parasitosis, improving their health and productivity, without the negative effects of AH. Ipomoea genus is a group of climbing plants belonging to the Convulvulaceae family possessing perennial leaves and tuberous roots. Medicinal properties has been attributed to this plant including nutritional agents, emetics, diuretics, diaphoretics, purgatives and pesticides. The objective of this study was assessing the in vitro nematocidal activity of a hydroalcoholic extract (HA-E) obtained from Ipomoea pauciflora (Cazahuate) flowers against Hc infective larvae (L3) and to identify its phytochemical profile (PhC-P). The assay was carried out using microtiter plates (MTP). Four HA-E concentrations were assessed and Ivermectin and distilled water were used as positive and negative control groups, respectively. Approximately 100 Hc L3 were deposited in each well (n=12) and incubated at 25-35°C for 7 days. Data were analyzed using ANOVA and a General Linear Model (GLM) followed by Tukey test (P<0.05). The treatments showing a concentration-dependent effect (CDE) were analyzed to identify their 50% and 90% lethal concentrations (CL50, 90) via a Probit Analysis. The highest mortality was observed at 50 mg/mL (82.64 ± 0.71%) and the lowest at 6.25 mg/mL (56.46 ± 2.49%), showing a CDE with increasing mortality from 6.25 to 50 mg/mL. The PhC-P revealed the presence of alkaloids, coumarins, flavonoids, tannins and triterpenes/ sterols. A HA-E from flowers of I. pauciflora will be considered to assess its potential use in the control of haemonchosis in small ruminants.

The Brown Alga Bifurcaria bifurcata Presents an Anthelmintic Activity on All Developmental Stages of the Parasitic Nematode Heligmosomoides polygyrus bakeri.

The current control of gastrointestinal (GI) parasitic nematodes mainly relies on the widespread use of anthelmintics, which has inevitably led to resistance. Therefore, there is an urgent need to find new sources of antiparasitic compounds. Macroalgae represent a rich source of active molecules and are widely described as having medicinal properties. In the present study, we investigated the potential anthelmintic activity of aqueous extracts from three species of algae (Bifurcaria bifurcata, Grateloupia turuturu and Osmundea pinnatifida) on the murine parasite Heligmosomoides polygyrus bakeri. Using a set of complementary in vitro tests, including larval development assays, egg hatching tests and nematicidal activity assays on larvae and adults, we report the nematicidal activity of aqueous extracts of B. bifurcata. In addition, aqueous extract fractionation using liquid/liquid partitioning with a solvent of increasing polarity was performed in order to identify the groups of active molecules underlying the anthelmintic activity. Non-polar extracts (heptane, ethyl acetate) demonstrated high anthelmintic potential, highlighting the role of non-polar metabolites such as terpenes. Here, we highlight the strong anthelmintic potential of the brown alga B. bifurcata on a mouse model of GI parasites, thus confirming the strong interest in algae as natural alternatives for the control of parasitic nematodes.

Potentials of Artocarpus altilis latex lectin (AaLL) as an antiproliferative, nematicidal, and insecticidal agent

Introduction and Aim: Plants are the most accessible and convenient source of lectins. Artocarpus altilis is a Moraceae plant utilized for its latex. The anti-proliferative, nematicidal, and insecticidal effects of this plant latex are unknown. The current study evaluates the antiproliferative, nematicidal, and insecticidal activity of pure AaLL on Triple Negative Breast Cancer cells, Meloidogyne incognita, and Spodoptera frugiperda, respectively.&#x0D; &#x0D; Materials and Methods: To assess AaLL's antiproliferative activity against MDA-MB-231, MTT and wound healing experiments were performed. Using juvenile mortality and feeding assays, the in vitro nematicidal and insecticidal activity against Meloidogyne incognita and Spodoptera frugiperda were evaluated.&#x0D; &#x0D; Results: The MTT experiment demonstrated that 5.4µg/ml AaLL effectively inhibited MDA-MB-231 growth by 50% compared to the control. Even at 40µg/ml, AaLL had no cytotoxic effects on NIH3T3 fibroblast cells. AaLL significantly reduced cell migration, with the wound area remaining at 41.95 percent as opposed to 4.57 percent in the control group. In vitro results on J2s exposed to AaLL for 72 hours demonstrated a death rate of 52% at a concentration of 30µg/ml. After 24 hours of incubation with 400µg/ml lectin, the insecticidal tests reveal that AaLL considerably reduces the weight of larvae. After 48 hours, a lectin concentration of 0.04% caused 69.44% larval death.&#x0D; &#x0D; Conclusion: This is the first report demonstrating the latex lectin from Artocarpus altilis's anti-proliferation, anti-migration, nematicidal, and insecticidal properties. Further research will be done on the signaling pathways and mechanism of action linked to these features.

Assembly and Analysis of Haemonchus contortus Transcriptome as a Tool for the Knowledge of Ivermectin Resistance Mechanisms.

Haemonchus contortus (Hc) is an important parasitic nematode of small ruminants. In this study we assembled the transcriptome of Hc as a model to contribute to the knowledge about the profile of the differential gene expression between two Mexican Hc strains under different anthelmintic resistance statuses, one susceptible and the other resistant to ivermectin (IVMs and IVMr, respectively), in order to improve and/or to have new strategies of control and diagnosis. The transcript sequence reads were assembled and annotated. Overall, ~127 Mbp were assembled and distributed into 77,422 transcript sequences, and 4394 transcripts of the de novo transcriptome were matched base on at least one of the following criteria: (1) Phylum Nemathelminthes and Platyhelminthes, important for animal health care, and (2) ≥55% of sequence identity with other organisms. The gene ontology (GO) enrichment analysis (GOEA) was performed to study the level of gene regulation to IVMr and IVMs strains using Log Fold Change (LFC) filtering values ≥ 1 and ≥ 2. The upregulated-displayed genes obtained via GOEA were: 1993 (for LFC ≥ 1) and 1241 (for LFC ≥ 2) in IVMr and 1929 (for LFC ≥ 1) and 835 (for LFC ≥ 2) in IVMs. The enriched GO terms upregulated per category identified the intracellular structure, intracellular membrane-bounded organelle and integral component of the cell membrane as some principal cellular components. Meanwhile, efflux transmembrane transporter activity, ABC-type xenobiotic transporter activity and ATPase-coupled transmembrane transporter activity were associated with molecular function. Responses to nematicide activity, pharyngeal pumping and positive regulation of synaptic assembly were classified as biological processes that might be involved in events related to the anthelmintic resistance (AR) and nematode biology. The filtering analysis of both LFC values showed similar genes related to AR. This study deepens our knowledge about the mechanisms behind the processes of H. contortus in order to help in tool production and to facilitate the reduction of AR and promote the development of other control strategies, such as anthelmintic drug targets and vaccines.

Alleviation of Meloidogyne incognita induced biotic stress in Daucus carota by nitrogen: Insights into cellular viability and reactive oxygen species of the host

Developing innovative nematode management solutions is becoming more important since ecologically hazardous nematicides are being phased out of the global markets. As a result, alternative measures that are less harmful to the environment are preferred for dealing with the root-knot nematodes which cause huge economic losses to farmers. This investigation was therefore, entailed to find the optimum nitrogen fertilizer rate to maximize plant growth promotion and upsurge nematicidal activity, while minimizing the harmful effects on environment. Among the various nitrogen fertilizer treatments from 50 kg/ha to 200 kg/ha, the most effective concentration was found to be 150 kg/ha N (U150Mi) at which significant (P ≤ 0.05) improvements in growth, yield, photosynthetic pigments, nitrate reductase activity (NRA), protein, and carbohydrate content of carrot were observed as compared to the nematode inoculated untreated plants. Scanning electron microscopy showed that compared to the untreated inoculated control, the stomatal characteristics of carrot improved significantly at U150Mi (150 kg/ha N). Laser confocal microscopy illustrated that nitrogen fertilizer markedly improved the cellular viability of carrot at U150Mi (150 kg/ha N) in comparison to nematode infected plants. Histochemical analysis revealed that the reactive oxygen species (ROS) marker, superoxide anion radicals were significantly scavenged by the enhanced antioxidant defense system of carrot at U150Mi (150 kg/ha N). In vitro studies demonstrate that nitrogen fertilizer has nematicidal properties that were dose dependent. Gall/egg mass indices and reproduction factor were dramatically reduced when U150Mi (150 kg/ha N) was applied to carrot plants inoculated with Meloidogyne incognita.

Sulfoxide-Containing Bisabolane Sesquiterpenoids with Antimicrobial and Nematicidal Activities from the Marine-Derived Fungus Aspergillus sydowii LW09.

Phytopathogens, such as phytopathogenic bacteria, fungi, and nematodes, have caused great losses of crops every year, seriously threatening human health and agricultural production. Moreover, marine-derived fungi are abundant sources of structurally unique and bioactive secondary metabolites that could be potential candidates for anti-phytopathogenic drugs. One new sulfoxide-containing bisabolane sesquiterpenoid aspersydosulfoxide A (1) and nine known analogues (2-10) were isolated from the marine-derived A. sydowii LW09. The absolute configuration of the sulfur stereogenic center in 1 was determined by electronic circular dichroism (ECD) calculations. Compound 5 showed inhibition activity against Pseudomonas syringae, with a minimum inhibitory concentration (MIC) value of 32 μg/mL, whereas, compounds 2, 7, and 8 showed antibacterial activities toward Ralstonia solanacarum, with the same MIC value at 32 μg/mL. Meanwhile, compounds 3, 7, and 8 inhibited the fungal spore germination of Fusarium oxysporum, with the half maximal effective concentration (EC50) values of 54.55, 77.16, and 1.85 μg/mL, respectively, while compounds 2, 3, 7, and 8 inhibited the fungal spore germination of Alternaria alternata, which could be induced by vacuolization of germ tubes, with EC50 values of 34.04, 44.44, 26.02, and 46.15 μg/mL, respectively. In addition, compounds 3, 7, and 8 exhibited nematicidal activities against Meloidogyne incognita second-stage juveniles (J2s). In addition, compound 8 possessed the strongest nematicidal activity of nearly 80% mortality at 60 h with the half lethal concentration (LC50) values of 192.40 μg/mL. Furthermore, compounds 3, 7, and 8 could paralyze the nematodes and then impair their pathogenicity.

Heterologous Expression and Bioactivity Determination of Monochamus alternatus Antibacterial Peptide Gene in Komagataella phaffii (Pichia pastoris)

Insects have evolved to form a variety of complex natural compounds to prevent pathogen infection in the process of a long-term attack and defense game with various pathogens in nature. Antimicrobial Peptides (AMPs) are important effector molecules of the insect immune response to the pathogen invasion involved in bacteria, fungi, viruses and nematodes. The discovery and creation of new nematicides from these natural compounds is a key path to pest control. A total of 11 AMPs from Monochamus alternatus were classified into 3 categories, including Attacin, Cecropin and Defensin. Four AMP genes were successfully expressed by Komagataella phaffii KM71. The bioassay results showed that the exogenous expressed AMPs represented antimicrobial activity against Serratia (G-), Bacillus thuringiensis (G+) and Beauveria bassiana and high nematicide activity against Bursaphelenchus xylophilus. All four purified AMPs' protein against B. xylophilus reached LC50 at 3 h (LC50 = 0.19 mg·mL-1 of MaltAtt-1, LC50 = 0.20 mg·mL-1 of MaltAtt-2 and MaltCec-2, LC50 = 0.25 mg·mL-1 of MaltDef-1). Furthermore, the AMPs could cause significant reduction of the thrashing frequency and egg hatching rate, and the deformation or fracture of the body wall of B. xylophilus. Therefore, this study is a foundation for further study of insect biological control and provides a theoretical basis for the research and development of new insecticidal pesticides.

Encapsulation of Ruta essential oil in chitosan and alginate matrices as an ecological alternative for the control of nematodes

Controlled release formulations of Ruta essential oil obtained by ionic gelation were developed. The presence of rue essential oil in the alginate and chitosan capsules was evidenced by Fourier transform infrared spectroscopy and differential scanning calorimetry. Release studies revealed that in acidic conditions (pH 4.2), the CHS-REO particles reached a Sw of 240% (w/w) in 30 days and 101% (w/w) for ALG-REO particles, generating a RR of 23.7% for CHS-REO and 20.4% for ALG-REO. On the other hand, at pH 6.8 it favored the Sw for ALG-REO 840% (w/w) and therefore the RR (45.6%) and disfavored the Sw of CHS-REO generating low RR (16.9%). Encapsulated rue essential oil showed equal or superior nematicidal activity against the nematode Melodogyne ssp., compared to free oil and a synthetic nematicide such as Carbofuran, without having a phytotoxic effect on the plant. This study revealed that REO encapsulated in biopolymeric matrices can be used as new nematicide formulations.

Study on Characterization and Pesticidal Evaluation of Diterpenes Isolated from Chloroform Extract of Hedychium spicatum Sm. Rhizomes

A chemical study on the rhizomes of Hedychium spicatum resulted in the isolation and identification of labdane diterpenes, hedychilactone A (1), and B (2). The chemical structure of known compounds 1 and 2 were elucidated based on extensive spectral data analyses and identified by comparing their experimental spectral data with the reported data in the literature. The isolated labdane diterpenes were evaluated for their pesticide effects like nematicidal activity on Meloidogyne incognita, insecticidal activity on Spodoptera litura, and herbicidal activity on Raphanus raphanistrum seeds. The bioactivity of both compounds was predicted with the help of in silico PASS studies. The proteins/enzymes undertaken for docking studies by AutoDock4.2 to validate nematicidal activity was acetylcholinesterase (PBD ID: IC2O), for insecticidal activity was enzyme carboxylesterase (PDB ID: 1CI8), and for herbicidal activity was acetohydroxyacid synthase (PBD ID: 1YHZ). These compounds could be deduced as a viable alternative source of natural pesticidal agents and pave the way for further studies on its mechanistic approaches and field trials to ascertain its pesticidal studies.

Micromeria biflora Benth: Phytochemical Analysis and in vitro Biological Investigations of Essential Oil with Concomitant in silico Molecular Docking, PASS Prediction and ADME/Tox Studies

Micromeria biflora Benth. (Lamiaceae) is an important medicinal herb used widely for treating the ailments like nose bleeds, toothaches, wounds, and sinusitis. The essential oil (EO) of Micromeria biflora collected from Bageshwar, Uttarakhand in India was examined by GC and GC/MS, which contributed 97.1% of the total essential oil. The EO was found to be dominated by E-caryophyllene (19.6%), geranial (16.2%), neral (11.5%) and caryophyllene oxide (10.8%). The EO was studied for antioxidant, antiamylase, nematicidal, antifeedant, insecticidal, antimicrobial and herbicidal activities. EO showed excellent insecticidal activity against Lipaphis erysimi with 96.33±0.18% inhibition whereas exhibited moderate mortality (78.66±2.08%) and egg hatchability (26.33±1.20%) against Meloidogyne incognita at 5 μL/mL. The EO was found significant against Raphanus raphanastrum with sprout inhibition of 96.33±0.33%, shoot length inhibition of 93.66±0.33% and root length inhibition of 95.66±0.33%, respectively for herbicidal activity compared to the standard pendimethalin (100.00±0.00%). It showed good to moderate antifungal activities against Curvularia lunata (88.14±0.37%) and Fusarium oxysporum (81.11±1.11%), antibacterial activity against Salmonella typhimurium (18.00±0.57 mm), Escherichia coli (17.33±0.33 mm), Staphylococcus aureus (23.33±0.66 mm) and Bacillus subtilis (18.66±0.33 mm). Similarly, a significant antifeedant activity (97.98%) against Spodoptera litura larvae was observed. The EO was found to show antioxidant and anti amylase activities. The probable mode of action of EO constituents using in-silico molecular docking, PASS prediction and ADME/Tox studies predicted that M. biflora can be a potential bioactive mixture of EO constituents for different biological activities.

Chemical composition and nematicidal activity of essential oil and piperitenone oxide of Mentha longifolia L. against Meloidogyne incognita

Chemical composition and nematicidal activity of essential oil and piperitenone oxide of Mentha longifolia L. against Meloidogyne incognita

GC-MS Analysis of the Essential Oil from Seseli mairei H. Wolff (Apiaceae) Roots and Their Nematicidal Activity.

The essential oil (EO) was extracted from aerial parts with insecticidal and fungicidal activity. Herein, the hydro-distilled essential oils of Seseli mairei H. Wolff roots were determined by GC-MS. A total of 37 components were identified, (E)-beta-caryophyllene (10.49%), β-geranylgeranyl (6.64%), (E)-2-decenal (6.17%) and germacrene-D (4.28%). The essential oil of Seseli mairei H. Wolff had nematicidal toxicity against Bursaphelenchus xylophilus with a LC50 value of 53.45 μg/mL. The subsequent bioassay-guided investigation led to the isolation of three active constituents: falcarinol, (E)-2-decenal, and octanoic acid. The falcarinol demonstrated the strongest toxicity against B. Xylophilus (LC50 = 8.52 μg/mL). The octanoic acid and (E)-2-decenal also exhibited moderate toxicity against B. xylophilus (LC50 = 65.56 and 176.34 μg/mL, respectively). The LC50 of falcarinol for the toxicity of B. xylophilus was 7.7 and 21 times than that of octanoic acid and (E)-2-decenal, respectively. Our findings demonstrate that the essential oil from Seseli mairei H. Wolff roots and their isolates may be developed as a promising natural nematicide.

Nematicidal Activity of Natural Products against Root-knot Nematode: A Review

Phylum Nematoda is the most abundant group among the metazoans. Root-knot nematodes (Meloidogyne spp.) are a serious threat to agrarian plants worldwide. RKN is among the most predominant spp. which affects a variety of plants and vegetables. It is challenging for farmers to manage these nematodes. The usage of nematicides is an efficient means of management of plant-parasitic nematodes. The continuous use of chemical nematicides can cause augmentation in cases of nematode resistance. In order to fulfill the requirement of modern sustainable agriculture along with safe environment and human health, there is need to switch over to natural remedies to control RKNs. Lately, many research studies have been carried out to isolate product from natural resources and evaluate their nematicidal activity against these nematodes. The present review provides a summary of nematicidal activity of the naturally derived substances against Meloidogyne incognita over the past few years.