Commercial Nematicide Research Articles

Nematicidal Activity of Volatiles against the Rice Root-Knot Nematode and Environmental Safety in Comparison to Traditional Nematicides.

The rice root-knot nematode (RRKN), Meloidogyne graminicola Golden and Birchfield 1965, is a dangerous crop pest that affects rice production on a global scale. The largest rice-producing countries struggle with the impacts of RRKN infestation, namely, underdeveloped plants and a reduction in rice grain that can reach up to 70% of crop yield. In addition, the shift to strategies of sustainable pest management is leading to a withdrawal of some of the most effective pesticides, given the dangers they pose to the environment and human health. Volatile metabolites produced by plants can offer safer alternatives. The present study characterized the nematicidal activity of volatile phytochemicals against the RRKN and compared the most active with commercial nematicides concerning their safety to the environment and human health. Rice plants were used to grow large numbers of RRKNs for direct-contact bioassays. Mortality induced by the volatiles was followed for four days on RRKN second-stage juveniles. Of the 18 volatiles tested, carvacrol, eugenol, geraniol, and methyl salicylate showed the highest mortalities (100%) and were compared to traditional nematicides using (eco)toxicological parameters reported on freely available databases. While methyl salicylate had a faster activity, carvacrol had more lasting effects. When compared to synthetic nematicides, these volatile phytochemicals were reported to have higher thresholds of toxicity and beneficial ecotoxicological parameters. Ultimately, finding safer alternatives to traditional pesticides can lower the use of damaging chemicals in farming and leverage the transition to agricultural practices with a lower impact on biodiversity.

Effectiveness of Some Commercial Nematicides on Both Root-Knot and Lesion Nematodes Parasitizing Date Palms in Egypt

Effectiveness of Some Commercial Nematicides on Both Root-Knot and Lesion Nematodes Parasitizing Date Palms in Egypt

Design, Synthesis, Nematicidal Evaluation, and Molecular Docking Study of Pyrano[3,2-c]pyridones against Meloidogyne incognita.

Root-knot nematodes pose a serious threat to crops by affecting production and quality. Over a period of time, substantial work has been done toward the development of effective and environmentally benign nematicidal compounds. However, due to the inefficiencies of previously reported synthetics in achieving the target of safe, selective, and effective treatment, it is necessary to develop new efficacious and safer nematicidal agents considering human health and environment on top priority. This work aims to highlight the efficient and convenient l-proline catalyzed synthesis of pyrano[3,2-c]pyridone and their use as potential nematicidal agents. In vitro results of larval mortality and egg hatching inhibition revealed maximum nematicidal activity against Meloidogyne incognita from compounds 15b, 15m, and 15w with LC50 values of 28.8, 46.8, and 49.18 μg/mL at 48 h, respectively. Under similar conditions, pyrano[3,2-c]pyridones derivatives 15b (LC50 = 28.8 μg/mL) was found at par with LC50 (26.92 μg/mL) of commercial nematicide carbofuran. The in vitro results were further validated with in silico studies with the most active compound 15b nematicidal within the binding to the pocket of acetylcholine esterase (AChE). In docking, binding free energy values for compound 15b were found to be -6.90 kcal/mol. Results indicated that pyrano[3,2-c]pyridone derivatives have the potential to control M. incognita.

Evaluation of Virgibacillus dokdonensis MCCC 1A00493 as a biological control agent and microbial organic fertilizer against root-knot nematodes

Root-knot nematodes (RKNs) can result in severe losses to crop production and economies. Virgibacillus dokdonensis MCCC 1A00493, a deep-sea bacterium, has demonstrated potent antagonistic effects against Meloidogyne incognita in vitro. However, the control efficacy under greenhouse and field conditions remains unclear. In this study, we investigated the nematicidal effect of MCCC 1A00493 fermentation liquid and its synergism with black soldier fly (BSF) larval frass organic fertilizer both in greenhouse and field experiments. MCCC 1A00493 fermentation liquid demonstrated a significant control efficacy on RKNs both in greenhouse and field experiments, with the highest control efficacy reaching 68.97 % and 74.87 %, respectively. Meanwhile, the synergistic effects of MCCC 1A00493 and BSF larvae frass organic fertilizer was investigated by adding 10 % suspension (1 × 109 CFU/mL) of MCCC 1A00493 into 71.51 kg of chicken manure organic fertilizer produced by co-conversion of BSF larvae and Bacillus subtilis BSF-CL. It was noted that MCCC 1A00493 microbial organic fertilizer reduced disease incidence of RKNs significantly both in greenhouse and field experiments, with the root gall index decreasing by 51.75 % and 63.22 %, respectively. MCCC 1A00493 fermentation liquid and microbial organic fertilizer demonstrated a control efficacy on RKNs exceeded commercial nematicide avermectin and commercial bio-organic fertilizer, respectively. In addition, MCCC 1A00493 fermentation liquid and microbial organic fertilizer had positive effects on the growth of tomato plants. These findings confirmed that V.dokdonensis MCCC 1A00493 as a biological control agent and microbial organic fertilizer have significant effect on RKNs and can be used as potential biocontrol preparations.

Chitin-enriched insect frass fertilizer as a biorational alternative for root-knot nematode (Meloidogyne incognita) management.

Root-knot nematodes (Meloidogyne spp.) are serious pests of most food crops, causing up to 100% yield loss. Nevertheless, commercial nematicides are costly and harmful to the environment. While the nematicidal potential of crustacean and synthetic chitin has been demonstrated globally, research on the potential of insect-derived chitin for nematode control has received limited attention. Here, seven chitin-fortified black soldier fly frass fertilizer extracts (chFE) were assessed for their suppressiveness of Meloidogyne incognita and impacts on spinach growth in comparison with a commercial nematicide using in vitro and in vivo bioassays. The performance of chFE and control treatments was assessed by determining their effects on nematode egg hatchability; infective juvenile (J2) mortality and paralysis; number of galls, egg masses, and J2s per plant; and spinach root and shoot biomass. In vitro results showed that chFE and commercial nematicide suppressed nematode egg hatchability by 42% and 52%, respectively, relative to the control (sterile distilled water). Up to 100% paralysis was achieved when M. incognita J2s were exposed to either chFE or commercial nematicide. Further, the J2 mortality achieved using chFE (95%) was comparable to the value achieved using commercial nematicide (96%); in all treatments, mortality increased with exposure time. Similarly, up to 85% suppression of gall development was achieved when spinach plants were grown in soil drenched with chFE; up to 79% reduction in egg mass formation and 68% suppression of J2 development in the root system were achieved using chFE. Also, chFE application significantly increased spinach root and shoot biomass by 54%-74% and 39%-58%, respectively, compared to commercial nematicide. Our findings demonstrate the nematicidal potential of chFE and its benefits on crop production. Thus, chFE could be considered as a promising multipurpose, regenerative, and cost-effective input for sustainable management of plant-parasitic nematodes and enhancement of crop yield.

Rational Design of a Potential New Nematicide Targeting Chitin Deacetylase.

In a previously published study, the authors devised a molecular topology QSAR (quantitative structure-activity relationship) approach to detect novel fungicides acting as inhibitors of chitin deacetylase (CDA). Several of the chosen compounds exhibited noteworthy activity. Due to the close relationship between chitin-related proteins present in fungi and other chitin-containing plant-parasitic species, the authors decided to test these molecules against nematodes, based on their negative impact on agriculture. From an overall of 20 fungal CDA inhibitors, six showed to be active against Caenorhabditis elegans. These experimental results made it possible to develop two new molecular topology-based QSAR algorithms for the rational design of potential nematicides with CDA inhibitor activity for crop protection. Linear discriminant analysis was employed to create the two algorithms, one for identifying the chemo-mathematical pattern of commercial nematicides and the other for identifying nematicides with activity on CDA. After creating and validating the QSAR models, the authors screened several natural and synthetic compound databases, searching for alternatives to current nematicides. Finally one compound, the N2-(dimethylsulfamoyl)-N-{2-[(2-methyl-2-propanyl)sulfanyl]ethyl}-N2-phenylglycinamide or nematode chitin deacetylase inhibitor, was selected as the best candidate and was further investigated both in silico, through molecular docking and molecular dynamic simulations, and in vitro, through specific experimental assays. The molecule shows favorable binding behavior on the catalytic pocket of C. elegans CDA and the experimental assays confirm potential nematicide activity.

Metarhizium carneum Formulations: A Promising New Biological Control to Be Incorporated in the Integrated Management of Meloidogyne enterolobii on Tomato Plants.

The increase in the populations of root-knot nematode Meloidogyne enterolobii in various vegetables such as tomatoes grown under greenhouse conditions as well as increasing restrictions on the use of certain chemical nematicides have led to the search for new, effective management strategies, preferably ones that are sustainable biological alternatives. In this work, two formulations of the nematophagous fungus Metarhizium carneum, one concentrated suspension and one wettable powder, were evaluated under greenhouse conditions to reduce the M. enterolobii infestation in tomato plants. In addition, the effectiveness of the liquid formulation of M. carneum was compared with two biological and three chemical commercial nematicides. The results show that the two M. carneum formulations reduced the M. enterolobii population density by 78 and 66% in relation to the control treatment. In comparison, the liquid formulation of M. carneum and Purpureocillium lilacinum treatments reduced nematode population density by 72 and 43%, respectively, while for metam sodium preplanting applications followed by M. carneum applications during the tomato growth stage, the reduction was 96%. The alternate use of some chemical compounds plus the application of M. carneum as a biocontrol is a good starting strategy for managing M. enterolobii populations. These results confirm that M. carneum is a serious candidate for the short-term commercialization of an environmentally friendly biological nematicide.

Effect of 4-Ethylbenzaldehyde from the Volatilome of Annona muricata on Meloidogyne incognita.

The demand for new soil fumigants has increased as a result of more restrictive legislation regarding the use of pesticides. In the present study, the potent nematicidal activity of volatile organic compounds released by the Annona muricata leaf macerate was demonstrated. In addition, we searched in the A. muricata volatilome for a molecule with potential to be developed as a new fumigant nematicide. In the greenhouse, even the lowest concentration of soursop leaf macerate tested (1.0%) as a biofumigant caused a significant (P < 0.05) reduction in Meloidogyne incognita infectivity and reproduction when compared with the nontreated control (0%). Forty-one compounds were identified through gas chromatography-mass spectrometry analysis, of which three (sabinene, caryophyllene oxide, and 4-ethylbenzaldehyde) were selected for studies against the nematode. Among these compounds, in in vitro trails, only 4-ethylbenzaldehyde showed nematicidal activity at 250 µg ml-1. The effective doses of 4-ethylbenzaldehyde predicted to kill 50 and 95% of the M. incognita second-stage juvenile population after 48 h of exposure were 35 and 88 µg ml-1, respectively. In in vitro tests, 4-ethylbenzaldehyde at 150 µg ml-1 reduced M. incognita egg hatching to values similar (P > 0.05) to those of the commercial nematicide fluensulfone at a concentration of 200 µg ml-1. In plant experiments, as a soil fumigant, 4-ethylbenzaldehyde at a dose of 1 ml/liter of substrate had an effect similar (P > 0.05) to that of the commercial fumigant Dazomet (250 µg ml-1). Therefore, 4-ethylbenzaldehyde shows potential for development as a new nematicide.

Essential Oil Volatiles as Sustainable Antagonists for the Root-Knot Nematode Meloidogyne ethiopica

Climate change is prompting a shift of tropical pests to locations with a previously lower probability of invasion. This is the case for root-knot nematodes, Meloidogyne sp., particularly of the tropical group. Among them, M. ethiopica is now considered a threat to European food security. The development of novel sustainable nematicides can be based on in vitro bioassays of highly active phytochemicals, e.g., volatiles from essential oils. However, a steady supply of nematodes is often very difficult and dependent on environmental conditions. In the present study, an in vitro co-culture system of M. ethiopica parasitizing hairy roots of Solanum lycopersicum was established, for the first time, to easily obtain populations of second-stage juveniles (J2). These were then used to screen the nematicidal activity of 10 volatile compounds characteristic of essential oils. Finally, information on the most successful compounds was reviewed to predict their environmental dispersion and ecotoxicological hazards. The M. ethiopica population obtained from the co-culture was morphologically similar to reported populations in natural conditions and could be accurately used in direct-contact bioassays. The aldehydes citral and citronellal induced complete mortality of the tested J2, at 1 mg/mL, while compounds from other chemical groups were not as successful. In comparison to commonly used commercial nematicides, citral and citronellal were less likely to accumulate in the water environmental compartment and have lower reported toxicities compared to aquatic organisms and to mammals. Overall, in vitro co-cultures showed the potential to expedite the screening and discovery of bioactive compounds as a contribution to the development of sustainable biopesticides, as well as to lower the impacts of modern farming on agroecosystems.

First Report on the Synergistic Interaction between Essential Oils against the Pinewood Nematode Bursaphelenchus xylophilus.

Control of the pinewood nematode (PWN), the causal agent of pine wilt disease, can be achieved through the trunk injection of nematicides; however, many pesticides have been linked to environmental and human health concerns. Essential oils (EOs) are suitable alternatives due to their biodegradability and low toxicity to mammals. These complex mixtures of plant volatiles often display multiple biological activities and synergistic interactions between their compounds. The present work profiled the toxicity of eight EOs against the PWN in comparison to their 1:1 mixtures, to screen for successful synergistic interactions. Additionally, the main compounds of the most synergistic mixtures were characterized for their predicted environmental fate and toxicity to mammals in comparison to emamectin benzoate, a commercial nematicide used against PWN. The mixtures of Cymbopogon citratus with Mentha piperita and of Foeniculum vulgare with Satureja montana EOs showed the highest activities, with half-maximal effective concentrations (EC50) of 0.09 and 0.05 µL/mL, respectively. For these, complete PWN mortality was reached after only ca. 15 min or 2 h of direct contact, respectively. Their major compounds had a higher predicted affinity to air and water environmental compartments and are reported to have very low toxicity to mammals, with low acute oral and dermal toxicities. In comparison, emamectin benzoate showed lower nematicidal activity, a higher affinity to the soil and sediments environmental compartments and higher reported oral and dermal toxicity to mammals. Overall, uncovering synergistic activities in combinations of EOs from plants of different families may prove to be a source of biopesticides with optimized toxicity against PWNs.

Selective control of parasitic nematodes using bioactivated nematicides.

Parasitic nematodes are a major threat to global food security, particularly as the world amasses 10 billion people amid limited arable land1-4. Most traditional nematicides have been banned owing to poor nematode selectivity, leaving farmers with inadequate means of pest control4-12. Here we use the model nematode Caenorhabditis elegans to identify a family of selective imidazothiazole nematicides, called selectivins, that undergo cytochrome-p450-mediated bioactivation in nematodes. At low parts-per-million concentrations, selectivins perform comparably well with commercial nematicides to control root infection by Meloidogyne incognita, a highly destructive plant-parasitic nematode. Tests against numerous phylogenetically diverse non-target systems demonstrate that selectivins are more nematode-selective than most marketed nematicides. Selectivins are first-in-class bioactivated nematode controls that provide efficacy and nematode selectivity.

Nanomaterials in Plant Protection against Parasitic Nemates

A review of current data on the effect of nanoparticles on phytoparasitic nematodes in the study in vitro and in planta and on plants infested with nematodes was carried out. Available data have shown that many nanoparticles of metals, metal oxides and non-metals have an effective nematicidal potential. According to the available data, NPs can have a direct toxic effect on nematodes, reduce the infection of plants during seed pretreatment or spraying, lead to inhibition of reproduction and development of the parasite in the roots, and their effectiveness may exceed known commercial nematicides. Some nanoparticles have an immunostimulatory effect on plants. Data on the mechanisms of action of NPs on nematodes are presented. An important mechanism for the toxicity of nanoparticles to nematodes may be the generation of reactive oxygen species (oxidative stress). Exposure to nanoparticles increased the expression of target genes involved in oxidative stress and DNA damage repair. A small number of works have dealt with nanonematicides, which in the form of nanocapsules have proven to be very effective against endoparasitic nematodes.

Impact of Certain Eco-Friendly Agents and Safety Commercial Nematicide Compared with The Chemical Nematicide Vydate for Controlling Meloidogyne javanica Infected Tomato Plants

Impact of Certain Eco-Friendly Agents and Safety Commercial Nematicide Compared with The Chemical Nematicide Vydate for Controlling Meloidogyne javanica Infected Tomato Plants

Efficacy of Six Commercial Nematicides against Root-Knot Nematode, Meloidogyne incognita and Their Impacts on Sugar Beet Plant Growth and Chemical Constituents

Efficacy of Six Commercial Nematicides against Root-Knot Nematode, Meloidogyne incognita and Their Impacts on Sugar Beet Plant Growth and Chemical Constituents

Sustainable management of the potato cyst nematode, Globodera rostochiensis, with two microbial fermentation products.

Potato cyst nematodes (PCN) cause an overall 9% yield loss of total potato production worldwide. Research on sustainable management of PCN is still under progress. Two microbial fermentation products (MFPs) from Alltech, a proprietary blend formulated with a bacterial fermentation media and a Cu component (MFP5075), and a microbial based product (MFP3048), were evaluated against the PCN Globodera rostochiensis. In laboratory tests, effectiveness of the MFPs was recorded in terms of PCN juveniles (J2) hatching from cysts, J2 mortality and their attraction toward potato roots using pluronic gel. Greenhouse trials were conducted to study the effect of the products on PCN infestation in potato plants and a pilot scale experiment was conducted to study the impact of these MFPs on nematode biodiversity in garden soil. All treatments were performed within a concentration range of 0, 0.5, 1, and 2% (v/v) MFP5075 and 2, 6, 10, and 20 g/10 ml (w/v) MFP3048. The attraction assay, juvenile hatching and the PCN infestation in plants results were compared with those in an untreated control and a commercial nematicide (Nemguard™) treatment. After 24 h of treatment with 0.5 and 1% MFP5075, a 13-fold and 43-fold reduction, respectively, relative to J2 survival was recorded compared to that of untreated control. However, no J2 survived at 2% and above concentration of the MFP5075 treatment. Treatment with MFP3048 was effective in causing mortality of J2 only after 48-h. In the attraction assay, a 20-fold and 8-fold reduction in number of J2 attracted toward potato roots was observed, when treated with MFP5075, compared to the untreated and the Nemguard™ treatment, respectively. Subsequently, 30–35 PCN cysts were treated with both products dissolved in potato root diffusate and the results were recorded in terms of number of J2 hatched in each treatment after 10 days. No J2 hatched in the MFP5075 treatment, whereas mean numbers (±SE) of 243 ± 11.5, 30 ± 2.5, and 1.3 ± 0.6 J2 were noted in the untreated control, MFP3048, and the Nemguard™ treatment, respectively. The treatment with the MFPs compromised the integrity of the unhatched J2, which looked granular, whereas the internal organs of the unhatched J2 could be clearly identified in the untreated control. In plant infestation studies, treatment with MFP3048 and MFP5075 caused 90.6 and 84.9 percent reduction in PCN infestation, respectively, in terms of cysts developed on roots compared to untreated control. Overall, results indicate that the MFPs could potentially provide a promising alternative for sustainable PCN management.

(R)-Carvone is a potential soil fumigant against Meloidogyne incognita whose likely enzymatic target in the nematode is acetylcholinesterase

To contribute to the development of new fumigant nematicides for the control of the plant-parasitic nematode Meloidogyne incognita, this study started with 31 volatile organic compounds reported as toxic to nematodes. At 500 μg/mL, α-ionone, (S)-carvone, (R)-carvone, 2-methylpropyl acetate, undecan-2-one, decan-2-one, and dodecan-2-one caused mortalities to M. incognita second-stage juveniles (J2) that were similar to those obtained with the commercial nematicides carbofuran (170 μg/mL) and fluensulfone (42.2 μg/mL). (R)-carvone, with a lethal concentration to 50% J2 (LC50) equal to 524 μg/mL, was selected for subsequent studies. When J2 were exposed to the (R)-carvone solution, the infectivity and reproduction on tomato were reduced. In the M. incognita egg hatching assay, (R)-carvone behaved like a true ovicide. When employed as a fumigant, (R)-carvone (3.9 g/L) was as efficient as the soil fumigant dazomet (0.245 g/L) in eliminating eggs of the nematode in a substrate to be used for tomato planting. According to in silico studies employing pharmacophoric searches and molecular docking, acetylcholinesterases are the target of (R)-carvone in the nematode.

Root-Knot Nematode (Meloidogyne incognita) Control Using a Combination of Lactiplantibacillus plantarum WiKim0090 and Copper Sulfate.

Lactic acid bacteria (LAB) exert antagonistic activity against root-knot nematodes, mainly by producing organic acids via carbohydrate fermentation. However, they have not yet been used for root-knot nematode (Meloidogyne incognita) control owing to a lack of economic feasibility and effectiveness. In this study, we aimed to isolate organic acid-producing LAB from kimchi (Korean traditional fermented cabbage) and evaluated their nematicidal activity. Among the 234 strains isolated, those showing the highest nematicidal activity were selected and identified as Lactiplantibacillus plantarum WiKim0090. Nematicidal activity and egg hatch inhibitory activity of WiKim0090 culture filtrate were dose dependent. Nematode mortality 3 days after treatment with 2.5% of the culture filtrate was 100%, with a 50% lethal concentration of 1.41%. In pot tests, the inhibitory activity of an L. plantarum WiKim0090-copper sulfate mixture on gall formation increased. Compared to abamectin application, which is a commercial nematicide, a higher control value was observed using the WiKim0090-copper sulfate mixture, indicating that this combination can be effective in controlling the root-knot nematode.

Nematicidal Effects of Volatile Organic Compounds from Microorganisms and Plants on Plant-Parasitic Nematodes.

Plant-parasitic nematodes (PPNs) are one of the most destructive plant pathogens worldwide, and controlling them is extremely challenging. Volatile organic compounds (VOCs), which naturally exist in plants and microorganisms, play an important role in the biological control of PPNs and are considered potential substances for the development of commercial nematicides. This paper summarizes the VOCs produced by microorganisms and plants as well as their toxic effects on PPNs. VOCs from 26 microbial strains and 51 plants that are active against nematodes from over the last decade were reviewed. Furthermore, the mechanisms of toxicity of some VOCs against PPNs are also illustrated.

Effectiveness of certain safety commercial nematicides compare with a chemical nematicide Carbofuran for controlling M. incognita infected pomegranate plants

Effectiveness of certain safety commercial nematicides compare with a chemical nematicide Carbofuran for controlling M. incognita infected pomegranate plants

Assessment of nematicidal activity of Beauveria bassiana (Bals.-Criv.) vuill on Pratylenchus thornei (Sher et Allen) (Tylenchida: Pratylenchidae)

In this study, nematicidal activity of two different isolates (BY2 and BIM-001) of the Beauveria bassiana (Bals.-Criv.) Vuill was investigated on Pratylenchus thornei Sher et Allen) (Tylenchida: Pratylenchidae) using culture filtrates and spore suspensions. Three spore suspensions (1x106, 1x107, 1x 108 spore/ml) and four culture filtrate concentrations (1X, 10X, 20X, 50X) were tested in the study. Depending on the treatment; 2 ml of spore suspensions or culture filtrates in different concentrations of both isolates and 400 larvae+adults from P. thornei were transferred to 6 mm petri dishes. The dead nematodes were counted under a light microscope after 24 and 72 hour and their mortality rate (%) were calculated. The nematicidal effect of culture filtrates of B. bassiana BY2 and BIM-001 isolates on P. thornei was found to be higher than the spore suspension. It was determined that the 1X concentration of culture filtrate of B. bassiana BY2 reached 100% mortality rate on P. thornei after 24 hour. After 72 hours, 10X (99.0%) concentrations of BY2 isolate and 1X (100%) and 10X (93.2%) concentrations of BIM isolate showed similar nematicidal activity with the commercial nematicide Velum (97.6%). On the other hand, after 72 hour, P. thornei mortality rate was 75.5% and 64.1%, respectively, at a concentration of 108 spore/ml of B. bassiana BY2 and BIM-001 isolates. This study will contribute to the development of a new control method as an alternative to the use of crop rotation and resistant cultivars in the control of P.thornei.