scholarly journals Efficacy of the Fungus Verticillium lecanii for Suppressing Root-knot Nematode Egg Numbers on Cantaloupe Roots

1999 ◽  
Vol 9 (3) ◽  
pp. 443-447 ◽  
Author(s):  
Susan L.F. Meyer
Keyword(s):  
Egg Production ◽  
Aqueous Suspension ◽  
Verticillium Lecanii ◽  
Root Knot Nematode ◽  
Inoculum Level ◽  
Heat Stable ◽  
Root And Shoot Growth ◽  
Granule Formulation ◽  
Root Tissues ◽  
Population Numbers

Two strains of the fungus Verticillium lecanii (A. Zimmermann) Viégas were studied as potential biocontrol agents for root-knot nematode (Meloidogyne incognita (Kofoid & White) Chitwood) on cantaloupe (Cucumis melo L.). For the study, pots were filled with soil that had been inoculated with M. incognita (inoculum was applied at two levels: 1000 and 5000 eggs/pot). Each fungus strain was applied individually by pouring an aqueous suspension (made from a wettable granule formulation) into the inoculated soil. Controls received water only. One cantaloupe seedling was then transplanted into each pot. Plants were grown for 55 days in the greenhouse, and then harvested and assessed for root and shoot growth and for nematode egg production. In pots inoculated with 1000 eggs/plant, neither fungus strain affected nematode egg numbers. At the 5000 eggs/plant inoculum level, both strains of the fungus suppressed egg numbers (counts were 28% and 31% less than water controls). Neither strain of V. lecanii affected the number of eggs embedded in root galls; the fungus suppressed nematode population numbers overall solely by affecting the number of eggs located outside of root tissues. Both fungus strains were also autoclaved and then applied to soil, to test for effects of nonviable fungus. In pots inoculated with 5000 eggs, application of one autoclaved strain resulted in a 35% suppression in egg numbers after 55 days, suggesting that the fungus produced a heat-stable substance deleterious to the nematode.

scholarly journals Trigonella foenum-graecum (fenugreek)-mediated suppression of Meloidogyne javanica in mungbean

2013 ◽  
Vol 55 (2) ◽  
pp. 121-132 ◽  
Author(s):  
Tayyaba Zia ◽  
Imran A. Siddiqui ◽  
Syed S. Shaukat ◽  
Syed Nazaru-Hasnai
Keyword(s):  
Meloidogyne Javanica ◽  
Macrophomina Phaseolina ◽  
Fungal Communities ◽  
Root Knot Nematode ◽  
Egg Hatch ◽  
Soil Suppressiveness ◽  
Juvenile Mortality ◽  
Trigonella Foenum Graecum ◽  
Root Tissues ◽  
Population Numbers

Soil amendments with powdered seeds of <i>Trigonella foenum - graecum</i> (fenugreek) caused soil suppressiveness against <i>Meloidogyne javanica</i>. Decomposed seeds of fenugreek caused marked reduction in nematode population densities and subsequent root-knot development as compared to the aqueous extract of the seeds indicating that some indirect factors are involved in the suppression of root-knot nematode. Both decomposed seeds and aqueous extracts enhanced plant height and fresh weights of shoot whereas root growth remained uninfluenced. Changes in fungal communities associated with nematode control were studied by comparing population numbers of fungi in the soil and in internal root tissues (endorhiza) in non-amended and fenugreekamended soils. <i>Acremonium</i> sp., <i>Chaetomium globosum, Fusarium solani, Macrophomina phaseolina</i> and <i>Rhizoctonia solani</i> were found to colonize inner root tissues of mungbean. <i>Acremonium</i> sp., <i>C. globosum</i> and <i>F.solani</i> were isolated in a relatively higher frequency from roots growing in the amended soils while <i>M. phaseolina</i> and <i>R. solani</i> colonized greatly in roots growing in non-amended soil. Of the fungi isolated from soils, <i>Penicillium brefaldianum</i> caused maximum juvenile mortality of <i>M.javanica</i> whereas <i>F.solani</i> caused greatest inhibition of egg hatch.

scholarly journals The role of Caenorhabditis elegans sex-determination homologs, Mi-sdc-1 and Mi-tra-1 in Meloidogyne incognita

2021 ◽  
Author(s):  
Anil Baniya ◽  
Soumi Joseph ◽  
Larry Duncan ◽  
William Crow ◽  
Tesfamariam Mengistu
Keyword(s):  
Caenorhabditis Elegans ◽  
Sex Determination ◽  
Meloidogyne Incognita ◽  
Egg Production ◽  
Target Genes ◽  
Parasitic Nematode ◽  
Plant Parasitic Nematode ◽  
Root Knot Nematode ◽  
Model Free ◽  
Plant Parasitic

AbstractSex determination is a key developmental event in all organisms. The pathway that regulates sexual fate has been well characterized at the molecular level in the model free-living nematode Caenorhabditis elegans. This study aims to gain a preliminary understanding of sex-determining pathways in a plant-parasitic nematode Meloidogyne incognita, and the extent to which the roles of the sex determination genes are conserved in a hermaphrodite species, C. elegans, and plant-parasitic nematode species, M. incognita. In this study, we targeted two sex-determining orthologues, sdc-1 and tra-1 from M. incognita using RNA interference (RNAi). RNAi was performed by soaking second-stage juveniles of M. incognita in a solution containing dsRNA of either Mi-tra-1or Mi-sdc-1 or both. To determine the effect of RNAi of the target genes, the juveniles treated with the dsRNA were inoculated onto a susceptible cultivar of cowpea grown in a nutrient pouch at 28 °C for 5 weeks. The development of the nematodes was analyzed at different time points during the growth period and compared to untreated controls. Our results showed that neither Mi-sdc-1 nor Mi-tra-1 have a significant role in regulating sexual fate in M. incognita. However, the silencing of Mi-sdc-1 significantly delayed maturity to adult females but did not affect egg production in mature females. In contrast, the downregulation of Mi-tra-1 transcript resulted in a significant reduction in egg production in both single and combinatorial RNAi-treated nematodes. Our results indicate that M. incognita may have adopted a divergent function for Mi-sdc-1 and Mi-tra-1distinct from Caenorhabditis spp. However, Mi-tra-1 might have an essential role in female fecundity in M. incognita and is a promising dsRNA target for root-knot nematode (RKN) management using host-delivered RNAi.

Third generation progress in breeding white clover for resistance to root-knot nematode

1996 ◽  
Vol 6 ◽  
pp. 163-166
Author(s):  
J. Van den Bosch ◽  
C.F. Mercer
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Egg Production ◽  
Control Method ◽  
Dry Weight ◽  
Third Generation ◽  
Root Knot Nematode ◽  
Root Dry Weight ◽  
Wide Range ◽  
Meloidogyne Sp

Root-knot nematode (Meloidogyne sp.) reduces growth and nutrition of white clover (Trifolium repens L.) in New Zealand, and breeding resistant cultivars (with low galls per gram of root) is the preferred control method. Resistant and susceptible selections were bred from a wide range of white clover lines for three generations. In the third generation there were significant differences between seed lines from the selections for number of galls, root dry weight, visual growth score and galls/gram of root dry weight. Resistant selections had 43% of the susceptible selections' galls per gram, and 50% of the number of galls. Germplasm showing resistance to Meloidogyne spp. in the USA showed partial resistance to the local Meloidogyne sp. Two resistant and two susceptible genotypes were also compared for nematode egg production; resistant genotypes had a mean of 3,460 eggs/plant, compared to 25,030 for susceptible genotypes. Keywords: breeding, Meloidogyne sp., resistance, rootknot nematode, screening, selection, Trifolium repens, white clover

scholarly journals Efficacy of Biorational Compounds against Mustard Aphid (Lipaphis erysimi Kalt.) and English Grain Aphid (Sitobion avenae Fab.) under Laboratory Conditions in Nepal

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Dipak Khanal ◽  
Salu Maharjan ◽  
Jamuna Lamichhane ◽  
Pritika Neupane ◽  
Srijana Sharma ◽  
...  
Keyword(s):  
Block Design ◽  
Aqueous Suspension ◽  
Pure Water ◽  
Sitobion Avenae ◽  
Lipaphis Erysimi ◽  
Control Treatment ◽  
Verticillium Lecanii ◽  
Mustard Aphid ◽  
Laboratory Conditions ◽  
Grain Aphid

Mustard aphid (Lipaphis erysimi) and English grain aphid (Sitobion avenae) are among the most important pests in mustard and wheat fields in Nepal. Biocide Manic (Metarhizium anisopliae a.i. = 1 × 109 spores/ml) at 3 ml/l water, Agri Sakti (Beauveria bassiana a.i. = 1 × 109 spores/ml) at 3.3 ml/l water, Varunastra (Verticillium lecanii spores 2% aqueous suspension, 2 × 108 CFU/ml) at 6 ml/l water, Mahastra (Bacillus thuringiensis var. kurstaki 0.5% wettable powder) at 6 g/l water, Neemraj Super (Azadirachitin 0.3% w/w) at 3.3 ml/l water, Tracer (Spinosad 90% spinosyns) at 0.33 ml/l water, and control treatment (pure water) were used to test their efficacy against L. erysimi and S. avenae, using leaf dip and spray methods under laboratory conditions in Rupandehi, Nepal, in the year 2018. Each treatment was replicated four times, and the experiment was carried out in a randomized complete block design. Mortality of aphids was recorded at 24, 48, 72, and 98 hours after treatment application. The result revealed highest mortality of mustard aphids with Agri Sakti at 24 hours after treatment (HAT); however, Neemraj Super was found to be the most effective at 48, 72, and 96 HAT with the leaf spray method. With the leaf dip method, Neemraj Super killed more mustard aphids than other treatments at all observed time points. Among tested biorational products, Agri Sakti was found to be most effective against English grain aphids in both leaf spray and leaf dip methods. In all the bioassays, the mortality caused by biorational compounds over control was highly significant. The present study suggests for further verification of the biorational products in the field and development of novel management strategies against different species of aphids.

scholarly journals Resistance to the Peanut Root-Knot Nematode (Meloidogyne arenaria) in Arachis hypogaea1

1992 ◽  
Vol 19 (1) ◽  
pp. 35-37 ◽  
Author(s):  
C. Corley Holbrook ◽  
James P. Noe
Keyword(s):  
Egg Production ◽  
Economic Losses ◽  
Egg Mass ◽  
Root Weight ◽  
Meloidogyne Arenaria ◽  
Root Knot Nematode ◽  
Sources Of Resistance ◽  
Plant Introductions ◽  
Nematode Eggs ◽  
Fresh Root

Abstract The peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1] causes significant economic losses throughout the peanut (Arachis hypogaea L.) production area of the southern United States. Chemicals for control of this pest are becoming increasingly limited, and there are no known sources of resistance within the U. S. A. hypogaea collection. The objectives of this research were to screen 1,321 plant introductions for resistance or hypersusceptibility based on egg-mass ratings in greenhouse tests and to conduct more intensive greenhouse studies of selected genotypes to evaluate this method for identifying resistance to the peanut root-knot nematode. Twenty-seven genotypes with low and eight genotypes with high egg-mass ratings were selected and reevaluated in a more intensive greenhouse experiment. Seventeen of the low selections supported fewer (P≤0.05) egg masses, and seven supported less egg production per gram of fresh root weight than Florunner. Three selections for high egg-mass ratings supported more nematode eggs per plant than the cultivar Florunner and had a greater host efficiency. One of these genotypes supported more nematode eggs per gram of fresh root weight than Florunner. These results show that resistance to M. arenaria exists in the cultivated peanut species and can be selected by rating egg-mass production on greenhouse-grown plants.

Effect of Steinernema feltiae-Xenorhabdus bovienii insect pathogen complex on Meloidogyne javanica

Nematology ◽  
2004 ◽  
Vol 6 (5) ◽  
pp. 671-680 ◽  
Author(s):  
Declan Fallon ◽  
Harry Kaya ◽  
Randy Gaugler ◽  
Brent Sipes
Keyword(s):  
Egg Production ◽  
Meloidogyne Javanica ◽  
Steinernema Feltiae ◽  
Root Penetration ◽  
Soybean Plant ◽  
Cortical Tissue ◽  
Root Knot Nematode ◽  
Colony Forming Units ◽  
Bacterial Treatment ◽  
Nematode Penetration

AbstractIsolates of Steinernema feltiae MG-14 from Hawaii and SN from France, and the symbiont Xenorhabdus bovienii from each nematode isolate, were tested for their glasshouse efficacy against the root-knot nematode, Meloidogyne javanica, on several vegetable plants. Steinernema feltiae application for 3-5 consecutive days at rates of 1000 or 10 000 infective juveniles (IJ) did not affect M. javanica root penetration and development in glasshouse pot experiments. IJ were recovered from the cortical tissue of tomatoes, soybeans, snow peas and cow peas. Xenorhabdus bovienii applied at 1010 colony-forming units (CFU) ml–1 reduced root-knot nematode penetration in cow peas but was ineffective in tomato or snow pea. Xenorhabdus bovienii metabolites had no effect on M. javanica root penetration and egg production in soybean. Soybean plant growth was unaffected by nematode and bacterial treatment; biomass was lower in M. javanica-infected soybean, irrespective of treatment, than in non-infected soybean, but the differences between the treatments were non-significant. Accordingly, the Steinernema feltiae-Xenorhabdus bovienii complex did not meet the objective for the suppression of M. javanica root penetration and development.

scholarly journals Inoculum Level and Inoculation Method Influences on the Pathogenic Activities of Meloidogyne incognita in Studied Model Plant Okra (Abelmoschus esculentus L. Moench)

2021 ◽  
pp. 82-92
Author(s):  
Yadom Y. F. R. Kouakou ◽  
Kouamé Daniel Kra ◽  
Hortense Atta Diallo
Keyword(s):  
Meloidogyne Incognita ◽  
Infected Plant ◽  
Correlation Coefficients ◽  
Root Knot Nematode ◽  
Reproductive Factor ◽  
Inoculum Level ◽  
Root Explants ◽  
Second Stage ◽  
Inoculation Method ◽  
Gall Index

Agricultural activities such as watering crops with nematode-infested water from wells and boreholes, and using infected plant debris as manure or mulch increase root-knot nematode infection. So, this study aims at assessing the influence of the inoculation method and inoculum level of Meloidogyne incognita on the development of root galls on okra plants. Two M. incognita inoculation methods (suspension of individuals and galled root explants) and six inoculum levels (0, 10, 100, 500, 1000 and 2000 second-stage larvae/plant) were studied. The gall index, total numbers and reproductive factor of M. incognita were used to assess the effect of treatments on root gall development. Unlike the reproductive factor, gall index and the total numbers of M. incognita increased with their inoculum level. The pathogenic activities of M. incognita were most significant when crop soils were infested with galled root explants. However, an inverse relationship was found between the inoculum levels of M. incognita and the okra plant’s development. It is reflected by negative correlation coefficients ranging from -0.90 to -0.62. It is therefore important to burn roots infected with root-knot nematodes left in fields so that they do not act as an inoculum for crops.

scholarly journals Reaction of Avena spp. to different concentration levels of Meloidogyne javanica and M. incognita inoculum

2020 ◽  
pp. 196-203
Author(s):  
Cláudia Fernanda Carraro- Lemes ◽  
Carolina Cardoso Deuner ◽  
Simone Meredith Scheffer- Basso ◽  
Valéria Cecília Ghissi Mazzetti ◽  
Jaqueline Huzar Novakowiski
Keyword(s):  
Meloidogyne Javanica ◽  
Nematode Species ◽  
Management Tool ◽  
Root Knot Nematode ◽  
Inoculum Level ◽  
Breeding Programs ◽  
Resistance Reaction ◽  
Different Response ◽  
Concentration Levels ◽  
Crotalaria Spectabilis

The objective of this study was to evaluate the resistance reaction of Avena spp. after inoculation of different concentrations of eggs and juveniles of M. javanica and M. incognita. Ten oat genotypes (Avena sativa: UPFPS Farroupilha, UPFA Ouro, IPR Afrodite, AF1345 Ucraniana; A. strigosa: Agro Quaraí, Agro Esteio, Embrapa 139, Iapar 61 Ibiporã, UPFA 21 Moreninha, AF 12202) were evaluated in bioassays for resistance against the root-knot nematodes, Meloidogyne javanica and M. incognita. Susceptible (Solanum lycopersicum and Glycine max) and resistant (Crotalaria spectabilis) species were used as control treatments. Depending on the inoculum level, the oats showed a different response to nematodes. All genotypes of oats were resistant to M. javanica when a high inoculum level (5,000 eggs and J2 per plant) was used but under low inoculum level (1,500 eggs and J2 per plant), AF 12202, Iapar 61 Ibiporã, Agro Esteio and Agro Quaraí were susceptible. All genotypes of oats were resistant to the inoculation of 2,900 eggs and J2 of M. incognita, except for ‘Iapar 61’ that showed susceptibility in this concentration. At lower inoculum level (1,500 eggs and J2) Agro Quaraí, Agro Esteio and Iapar 61 Ibiporã were susceptible. The reaction of oats to M. javanica and M. incognita depends on the inoculum level. The resistance reaction at low inoculum density of A. sativa ‘AF 1345 Ucraniana’ and ‘IPR Afrodite’ allows its use in breeding programs in oats and suggests the possibility of management tool in areas infested with both root-knot nematode species.

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