Activity of Saponins from Medicago Species against Phytoparasitic Nematodes

Content of bioactive saponins of Medicago species suggests that they may also exert, as previously demonstrated on M. sativa, nematicidal properties exploitable for the formulation of new products for sustainable phytoparasitic nematode management. This study was addressed to highlight the bioactivity of saponins from five different Medicago species still poorly known for their biological efficacy, i.e., M. heyniana, M. hybrida, M. lupulina, M. murex and M. truncatula, against the plant parasitic nematodes Meloidogyne incognita, Xiphinema index and Globodera rostochiensis. The bioactivity of the extracts from the five Medicago species was assessed by in vitro assays on the juveniles (J2) and eggs of M. incognita and G. rostochiensis and the adult females of X. index. The suppressiveness to M. incognita of soil treatments with the Medicago plant biomasses was also investigated in a tomato experiment. The nematicidal activity of the five Medicago species was reported and discussed in relation to their phytochemical profile.

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Toxicity of ethanol solutions and vapours against Meloidogyne incognita

Nematology ◽

10.1163/15685411-00003046 ◽

2017 ◽

Vol 19 (3) ◽

pp. 271-280 ◽

Cited By ~ 6

Author(s):

Julio C.P. Silva ◽

Vicente P. Campos ◽

Eduardo S. Freire ◽

Willian C. Terra ◽

Liliana E. Lopez

Keyword(s):

Root System ◽

Meloidogyne Incognita ◽

Parasitic Nematodes ◽

Infested Soil ◽

Large Reduction ◽

Plant Parasitic Nematodes ◽

Second Stage ◽

Plant Parasitic

Ethanol (EtOH) is less harmful to humans than currently available nematicide molecules. This study evaluated the efficacy of EtOH in controlling Meloidogyne incognita in vitro and in lettuce plants under glasshouse conditions. Aqueous EtOH solutions (5-70% volume) and their vapours caused an acute nematicidal effect in vitro in second-stage juveniles (J2) of M. incognita and reduced hatching of J2. There was a large reduction of galls and eggs in the root system when 40 ml of EtOH was applied to M. incognita-infested soil at concentrations of 40 and 70%. Water exposed to EtOH vapours for 1 h became toxic, and a 12-h exposure caused 100% J2 mortality. Use of a plastic cover did not increase the efficiency of EtOH in controlling M. incognita in lettuce plants. The observed EtOH effects indicate its prospective use in controlling plant-parasitic nematodes, especially in glasshouses.

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Plant Parasitic Nematodes Associated with Plantain (Musa acuminata x M. balbisiana, AAB) in Puerto Rico

The Journal of Agriculture of the University of Puerto Rico ◽

10.46429/jaupr.v66i1.7640 ◽

1969 ◽

Vol 66 (1) ◽

pp. 52-59

Author(s):

D. Oramas ◽

J. Román

Keyword(s):

Puerto Rico ◽

Meloidogyne Incognita ◽

Nematode Species ◽

Musa Acuminata ◽

Parasitic Nematodes ◽

Radopholus Similis ◽

Plant Parasitic Nematodes ◽

Rotylenchulus Reniformis ◽

Phytoparasitic Nematodes ◽

Plant Parasitic

A survey was conducted through the five argricultural regions of Puerto Rico to determine distribution and population density of the nematode species associated with plantain. Fourteen genera, represented by 19 species of phytoparasitic nematodes were found in association with the crop: Ditylenchus, Helicotylenchus, Hoplolaimus, longidorus, Meloidogyne, Paratylenchus, Pratylenchus, Pseudhalenchus, Quinisulcius, Radopholus, Rotylenchulus, Tylenchorhynchus, Tylenchus, and Xiphinema. Meloidogyne incognita, Helicotylenchus spp., Radopholus similis, and Rotylenchulus reniformis were the most widely distributed nematode species throughout the Island. On the other hand, M. incognita, P. coffeae, R. similis, Helicotylenchus spp. , and R. reniformis had higher population densities.

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Activity of Hydroxamic Acids from Secale cereale Against the Plant-Parasitic Nematodes Meloidogyne incognita and Xiphinema americanum

Phytopathology ◽

10.1094/phyto-95-1116 ◽

2005 ◽

Vol 95 (10) ◽

pp. 1116-1121 ◽

Cited By ~ 20

Author(s):

I. A. Zasada ◽

S. L. F. Meyer ◽

J. M. Halbrendt ◽

C. Rice

Keyword(s):

Secale Cereale ◽

Meloidogyne Incognita ◽

Degradation Products ◽

Hydroxamic Acids ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Egg Hatch ◽

Starting Point ◽

Plant Parasitic

Cyclic hydroxamic acids are secondary metabolites found in the family Poaceae and have been implicated in the allelopathy of rye (Secale cereale). The toxicity of these compounds against plant-parasitic nematodes is unknown. DIBOA (2,4-dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one), DIMBOA (2,4-hydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one), and their degradation products BOA (benzoxazolin-2(3H)-one) and MBOA (6-methoxy-benzoxazolin-2(3H)-one) were screened in vitro against Meloidogyne incognita second-stage juveniles (J2) and eggs and mixed-stages of Xiphinema americanum. Xiphinema americanum was more sensitive to DIBOA and DIMBOA than M. incognita J2, with a maximum apparent mortality of 96 and 92% compared to 73 and 72% at 90 μg/ml. Eggs of M. incognita were less sensitive to the hydroxamic acids than J2; only DIBOA resulted in a 50% reduction in egg hatch, with a lethal concentration (LC50) of 74 μg/ml compared to 21 μg/ml for J2. When M. incognita J2 were exposed to DIBOA for 48 h and the compound was removed and replaced with water, the LC50 value increased from 21.0 to 40.7 μg/ml. MBOA was not toxic to X. americanum or M. incognita eggs, but was toxic to M. incognita J2, with LC50 values of 44 and 20 μg/ml before and after the compound was removed and replaced with water. BOA was the least toxic hydroxamic acid tested; it did not reduce M. incognita egg hatch after 1 week of exposure or increase X. americanum mortality after 24 h of exposure. While in vitro studies provide a valuable starting point in determining the toxicity of the chemical component of rye, the relevance of the data to soil remains to be determined.

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Allelopathy: a possible mechanism of suppression of plant-parasitic nematodes by entomopathogenic nematodes

Nematology ◽

10.1163/156854199508766 ◽

1999 ◽

Vol 1 (7) ◽

pp. 735-743 ◽

Cited By ~ 32

Author(s):

Parwinder S. Grewal ◽

Edwin E. Lewis ◽

Sudha Venkatachari

Keyword(s):

Meloidogyne Incognita ◽

Entomopathogenic Nematodes ◽

Galleria Mellonella ◽

Steinernema Feltiae ◽

Symbiotic Bacteria ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Tomato Roots ◽

Xenorhabdus Nematophilus ◽

Plant Parasitic

Abstract A possible mechanism of suppression of a plant-parasitic nematode Meloidogyne incognita by entomopathogenic nematodes is described. Heat-killed entomopathogenic nematodes Steinernema feltiae and S. riobrave temporarily suppressed penetration of the root-knot nematode M. incognita into tomato roots, but live nematodes had no effect. Infective juvenile M. incognita were repelled from all entomopathogenic nematode treatments that included their symbiotic bacteria. They were repelled by Galleria mellonella cadavers infected with S. carpocapsae, S. feltiae, and S. riobrave and from cell-free culture filtrates of the symbiotic bacteria Xenorhabdus nematophilus, X. bovienii, and Xenorhabdus sp. "R" from the three nematode species, respectively. Cell-free filtrates from all three Xenorhabdus spp. were toxic to M. incognita infective juveniles causing 98-100% mortality at 15% concentration. Cell-free filtrate of Xenorhabdus sp. "R" also reduced the hatch of M. incognita eggs. Application of formulated bacterial cell-free filtrates temporarily suppressed M. incognita penetration into tomato roots in a greenhouse trial. The short-term effects of cell-free bacterial filtrates, namely toxicity and repellency, were almost entirely due to ammonium. These results demonstrate allelopathic interactions between plant-parasitic nematodes, entomopathogenic nematodes and their symbiotic bacteria. The likely role of allelopathy in the suppression of plant-parasitic nematodes by innundative applications of entomopathogenic nematodes is discussed. Allelopathie: Ein moglicher Mechanismus zur Unterdruckung pflanzenparasitarer Nematoden durch insektenpathogene Nematoden - Es wird ein moglicher Mechanismus zur Unterdruckung des pflanzenparasitaren Nematoden Meloidogyne incognita durch insektenpathogene Nematoden beschrieben. Durch Hitze abgetotete insektenpathogene Nematoden Steinernema feltiae und S. riobrave underdruckten das Eindringen des Wurzelgallenalchens M. incognita in Tomatenwurzeln, lebende Nematoden hatten keine Wirkung. Infektionsjuvenile von M. incognita wurden von allen Behandlungen mit insektenpathogenen Nematoden abgestossen, die auch die symbiontischen Bakterien einschlossen. Sie wurden durch die Kadaver von Galleria mellonella abgestossen, die mit S. carpocapsae, S. feltiae und S. riobrave infiziert waren sowie durch zellfreie Kultursubstrate der symbiontischen Bakterien Xenorhabdus nematophilus, X. bovienii und Xenorhabdus sp. "R" aus den drei genannten Nematodenarten. Zellfreie Kultursubstrate von allen drei Xenorhabdus spp. waren giftig fur die Infektionsjuvenilen von M. incognita und verursachten in einer Konzentration von 15% Abtotungsraten von 98-100%. Zellfreie Kultursubstrate von Xenorhabdus sp. "R" vermiderten ausserdem das Schlupfen von M. incognita-Eiern. In einem Gewachshausversuch unterdruckten formulierte zellfreie Bakterienfiltrate vorubergehend das Eindringen von M. incognita in Tomatenwurzeln. Die Kurzzeitwirkungen von zellfreien Bakterien filtraten, namentlich Giftigkeit und Abstossung, waren nahezu ganz bedingt durch Ammoniak. Diese Ergebnisse zeigen das Vorhandensein von allelopathischen Wechselwirkungen zwischen pflanzenparasitaren Nematoden, insektenpathogenen Nematoden und deren symbiontischen Bakterien. Die wahrscheinliche Rolle von Allelopathie bei der Unterdruckung pflanzenparasitarer Nematoden durch eine Massenanwendung insektenpathogener Nematoden wird diskutiert.

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Combinatorial in vitro RNAi of two neuropeptide genes and a pharyngeal gland gene on Meloidogyne incognita

Nematology ◽

10.1163/15685411-00002859 ◽

2015 ◽

Vol 17 (2) ◽

pp. 155-167 ◽

Cited By ~ 6

Author(s):

Prakash Banakar ◽

Amita Sharma ◽

Catherine J. Lilley ◽

Nagavara Prasad Gantasala ◽

Mukesh Kumar ◽

...

Keyword(s):

Meloidogyne Incognita ◽

Parasitic Nematodes ◽

Specific Gene ◽

Plant Parasitic Nematodes ◽

Rnai Silencing ◽

Transcript Quantification ◽

The Central Nervous System ◽

Pharyngeal Gland

Root-knot nematodes are the most economically important group of plant-parasitic nematodes. In the present study, functional validation using in vitro RNAi was carried out on Meloidogyne incognita with two FMRFamide-like peptide genes, flp-14 and flp-18, and a subventral pharyngeal gland specific gene, 16D10. It was found that RNAi silencing of each gene reduced the attraction of M. incognita at different time intervals both in combination and individually. Silencing of the genes reduced nematode infection by 23-30% and development as indicated by a reduction in the number of females by 26-62%. Reproduction was decreased by 27-73% and fecundity was decreased by 19-51%. In situ hybridisation revealed the expression of flp-18 in cells associated with the ventral and retro vesicular ganglia of the central nervous system. qRT-PCR supported the correlation between phenotypic effects of silencing with that of transcript quantification.

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Short-Term Effects of Sublethal Doses of Nematicides on Meloidogyne incognita

Phytopathology ◽

10.1094/phyto-11-18-0420-r ◽

2019 ◽

Vol 109 (9) ◽

pp. 1605-1613 ◽

Cited By ~ 10

Author(s):

Catherine L. Wram ◽

Inga A. Zasada

Keyword(s):

Population Density ◽

Meloidogyne Incognita ◽

Cultivated Plants ◽

Parasitic Nematodes ◽

Initial Population ◽

Plant Parasitic Nematodes ◽

Water Control ◽

Effective Doses ◽

Sublethal Doses ◽

Plant Parasitic

Meloidogyne species are one of the most important groups of plant-parasitic nematodes globally because of their ability to damage most cultivated plants. Although they are widespread and economically important, there are limited control measures to combat these nematodes. New nonfumigant nematicides have been discovered that have the potential to be widely utilized for the management of plant-parasitic nematodes. Because of the longer half-lives in soil and lower toxicity of new nematicides compared with traditional fumigant and nonfumigant nematicides, understanding how nematodes respond to sublethal doses of nematicides is imperative to understanding whether nematicide resistance has the potential to develop. Characterizing responses of nematodes to sublethal doses will provide the foundation for future work, such as gene expression studies. In this study, the nematicides oxamyl (Vydate), fluazaindolizine (Salibro), fluensulfone (Nimitz), and fluopyram (Velum), were evaluated to understand how sublethal doses affect the fecundity and mobility of Meloidogyne incognita second-stage juveniles (J2). Using a microwell assay system, dose-response curves for each nematicide were established for M. incognita J2. Fluopyram was the most toxic nematicide, with effective doses up to 230 times lower than that of other nematicides. The other nematicides had predicted ED50 values (effective doses that resulted in 50% of the population becoming inactive) of 89.4, 131.7, and 180.6 ppm for oxamyl, fluensulfone, and fluazaindolizine, respectively. The 24-h ED50 of each nematicide was then used in both motility and infectivity assays. The motility and activity of M. incognita J2 exposed to ED50 doses of fluazaindolizine and fluensulfone was significantly reduced, with nematodes initially being motile but eventually becoming inactive. However, the motility of M. incognita J2 exposed to ED50 doses of fluopyram and oxamyl was not different from a water control. In a pot assay, M. incognita J2 exposed to ED50 doses of fluazaindolizine, oxamyl, and fluensulfone were unable to reproduce on tomato, with reproduction factors (RF = final population density/initial population density) of 0 to 0.03. Fluopyram did not reduce reproduction of M. incognita, with a mean RF of 38.7 ± 4.5, which was similar to the RF of 46.3 ± 4.6 for the water control. This study is the first comprehensive evaluation of M. incognita activity, motility, and fecundity after exposure to the traditional nematicide, oxamyl, as well as three new nematicides, fluazaindolizine, fluopyram, and fluensulfone.

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Biological attributes of Salibro™, a novel sulfonamide nematicide. Part 2: Impact on the fitness of various non-target nematodes

Nematology ◽

10.1163/15685411-bja10041 ◽

2020 ◽

pp. 1-17 ◽

Cited By ~ 1

Author(s):

Tim C. Thoden ◽

Mariam A. Alkader ◽

John A. Wiles

Keyword(s):

Negative Impact ◽

Soil Health ◽

Agar Plate ◽

Parasitic Nematodes ◽

Published Data ◽

Plant Parasitic Nematodes ◽

Free Living ◽

Plant Parasitic ◽

Novel Products

Summary Currently a renaissance in chemical nematicides is taking place with novel products like Nimitz® (a.s. fluensulfone), Velum Prime® (a.s. fluopyram) and Salibro™ (a.s. fluazaindolizine – Reklemel™ active) entering the marketplace. Although a considerable amount of published data is already available on their laboratory and field impact on plant-parasitic nematodes, little is understood of their compatibility with the beneficial or free-living nematodes that are part of the soil health network. In a range of laboratory studies, the effects of these nematicides on the vitality and reproduction of several species was tested, including both cosmopolitan free-living nematodes (Acrobeloides, Cruznema, Panagrobelus) as well as commercially applied entomopathogenic nematodes (Steinernema, Heterorhabditis). Within aqueous exposure and agar plate in vitro assays, species sensitivity to those nematicides differed significantly but their fitness (vitality and reproduction; infectivity to insect hosts) was generally not adversely impacted by concentrations of 5-50 ppm (a.s.) of Salibro. Even at 250 ppm (a.s.) of Salibro only some species of the bacterial-feeding species showed some negative impact. By contrast, both Nimitz at 50 ppm (a.s.) and Velum at 5 ppm (a.s.) consistently demonstrated stronger adverse impacts. In second level soil drenching assays, either no, or occasionally slight, adverse effects on the natural community of free-living nematodes were observed if soils were drenched with different volumes of Salibro at 5-50 ppm (a.s.), while relatively stronger reductions were measured within the plant-parasitic species (especially root-knot nematodes). Both Nimitz and Vydate (a.s. oxamyl) showed some degree of compatibility at 5 and 25 ppm (a.s.), respectively, which was generally higher than for Velum Prime at 5 ppm (a.s.). Overall, these data indicate that, when used at common field rates, Salibro will be one of the best options as part of integrated nematode management programmes where the use of chemical nematicides is required.

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Differential Response of Meloidogyne, Pratylenchus, Globodera, and Xiphinema Species to the Nematicide Fluazaindolizine

Phytopathology ◽

10.1094/phyto-05-20-0189-r ◽

2020 ◽

Vol 110 (12) ◽

pp. 2003-2009

Author(s):

Catherine L. Wram ◽

Inga Zasada

Keyword(s):

Untreated Control ◽

Exposure Dose ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Response Curves ◽

Greenhouse Study ◽

Meloidogyne Spp ◽

The Impact ◽

Plant Parasitic

This research focused on the effects of fluazaindolizine on a diversity of plant-parasitic nematodes. In microwell assays, 24-h dose-response curves were generated for several species and populations of Meloidogyne, Pratylenchus neglectus, P. penetrans, Globodera ellingtonae, and Xiphinema americanum. In a greenhouse study, the impact of fluazaindolizine on fecundity of M. incognita, M. hapla, and M. chitwoodi was tested by exposing nematodes for 24 h in solution and inoculating on tomato. The average 24-h ED50s (dose that resulted in the immobility of 50% of exposed nematodes) for M. hapla, M. chitwoodi, and M. incognita were 325.7, 223.4, and 100.7 ppm, respectively. M. hapla had the most variation among populations, with 24-h ED50s ranging from 72 to 788 ppm. G. ellingtonae had the lowest 24-h ED50 at 30 ppm. Pratylenchus spp. were unaffected by fluazaindolizine. X. americanum was the only species where effects of fluazaindolizine were reversible, but had a 24-h ED50 that fell in the range of the Meloidogyne spp. In the greenhouse study, M. chitwoodi was the least sensitive with reproduction reaching 62% of the untreated control after a pre-exposure to 47 ppm, whereas M. incognita and M. hapla at the same exposure dose had reproduction rates of 27 and 36% of the untreated control, respectively. Despite varying in in vitro responses to fluazaindolizine, reproduction of all Meloidogyne spp. was suppressed after only 24 h of exposure. This study expanded our understanding of how G. ellingtonae, P. thornei, P. penetrans, and X. americanum respond to fluazaindolizine.

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The use of Pluronic F-127 to study the development of the potato cyst nematode, Globodera pallida

Nematology ◽

10.1163/156854112x631944 ◽

2012 ◽

Vol 14 (7) ◽

pp. 869-873 ◽

Cited By ~ 5

Author(s):

Ayano Sasaki-Crawley ◽

Rosane Curtis ◽

Michael Birkett ◽

Apostolos Papadopoulos ◽

Rod Blackshaw ◽

...

Keyword(s):

Aqueous Solution ◽

Solanum Tuberosum ◽

Transgenic Plants ◽

Cyst Nematode ◽

Potato Cyst Nematode ◽

Globodera Pallida ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Plant Parasitic

This paper demonstrates a simple novel in vitro method using Pluronic F-127 aqueous solution to study the development of the potato cyst nematode, Globodera pallida, in Solanum spp. without any need for sterilisation of either the plants or the nematodes. In this study, this method was successfully applied to comparative studies on the development of G. pallida in Solanum tuberosum (potato) or S. sisymbriifolium (sticky nightshade). The protocol described here could be useful for screening transgenic plants or different plant cultivars/species for their ability to allow development not only of G. pallida but also any other plant-parasitic nematodes.

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Responses of Heterodera glycines and Meloidogyne incognita to exogenously applied biogenic amines

Nematology ◽

10.1163/156854108786161436 ◽

2008 ◽

Vol 10 (6) ◽

pp. 911-917 ◽

Cited By ~ 6

Author(s):

Edward Masler

Keyword(s):

Biogenic Amines ◽

Meloidogyne Incognita ◽

Head Movement ◽

Heterodera Glycines ◽

Parasitic Nematodes ◽

Stage Juvenile ◽

Quantitative Analyses ◽

Effective Doses ◽

Plant Parasitic

AbstractHatching and head movement behaviours of second-stage juvenile (J2) of two agriculturally important plant-parasitic nematodes were affected by the in vitro application of biogenic amines. The behavioural responses of Heterodera glycines and Meloidogyne incognita to treatments of serotonin, octopamine and dopamine were qualitatively similar, but significant quantitative differences between the species were revealed. The frequency of J2 head movement was decreased by as little as 250 μM serotonin in H. glycines and 500 μM serotonin in M. incognita, with effective doses (ED50) of 0.73 mM for H. glycines and 1.72 mM for M. incognita. Octopamine had the opposite effect of serotonin, increasing J2 head movement frequency at thresholds of 2 mM in H. glycines and 1 mM in M. incognita. Octopamine ED50 values were 32.35 mM and 1.91 mM, respectively. Dopamine had no effect on head movement in either species up to concentrations of 20 mM. Serotonin inhibited hatch in both species but was more potent against H. glycines (90% inhibition at 1 mM) than M. incognita (40% inhibition at 5 mM). Octopamine reduced hatch equally in both species with over 95% inhibition at 80 mM. Dopamine had no effect on hatch in M. incognita but did inhibit H. glycines hatch over 60% at 40 mM. The value of detailed quantitative analyses of plant-parasitic nematode responses to biogenic amines for studies on nematode control is discussed.

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