scholarly journals Effect of Meloidogyne incognita Inoculum Density and Application Rate of Paecilomyces lilacinus Strain 251 on Biocontrol Efficacy and Colonization of Egg Masses Analyzed by Real-Time Quantitative PCR

2011 ◽  
Vol 101 (1) ◽  
pp. 105-112 ◽  
Author(s):  
S. Kiewnick ◽  
S. Neumann ◽  
R. A. Sikora ◽  
J. E. Frey
Keyword(s):  
Real Time ◽  
Meloidogyne Incognita ◽  
Quantitative Polymerase Chain Reaction ◽  
Application Rate ◽  
Paecilomyces Lilacinus ◽  
Egg Mass ◽  
Root Knot Nematode ◽  
Inoculum Level ◽  
Egg Masses ◽  
Biocontrol Efficacy

The fungal biocontrol agent, Paecilomyces lilacinus strain 251 (PL251), was evaluated for its potential to control the root-knot nematode Meloidogyne incognita on tomato at varying application rates and inoculum densities. Conversely to previous studies, significant dose-response relationships could not be established. However, we demonstrated that a preplanting soil treatment with the lowest dose of commercially formulated PL251 (2 × 105 CFU/g soil) was already sufficient to reduce root galling by 45% and number of egg masses by 69% when averaged over inoculum densities of 100 to 1,600 eggs and infective juveniles per 100 cm3 of soil. To determine the role of colonization of M. incognita egg masses by PL251 for biocontrol efficacy, a real-time quantitative polymerase chain reaction (PCR) assay with a detection limit of 10 CFU/egg mass was used. Real-time PCR revealed a significant relationship between egg mass colonization by PL251 and the dose of product applied to soil but no correlation was found between fungal density and biocontrol efficacy or nematode inoculum level. These results demonstrate that rhizosphere competence is not the key mode of action for PL251 in controlling M. incognita on tomato.

scholarly journals Investigating the in vitro and in vivo nematicidal performance of structurally related macrolides against the root-knot nematode, Meloidogyne incognita

2019 ◽  
Vol 12 (1) ◽  
pp. 24-37
Author(s):  
M.A. Radwan ◽  
A.S.A. Saad ◽  
H.A. Mesbah ◽  
H.S. Ibrahim ◽  
M.S. Khalil
Keyword(s):  
Meloidogyne Incognita ◽  
Root Length ◽  
Egg Mass ◽  
Root Knot Nematode ◽  
Egg Hatching ◽  
Shoot Height ◽  
Egg Masses ◽  
New Family

Summary Avermectins and spinosyns are structurally related natural products of microbial origin and belong to a new family of macrolides which are active against a vast array of invertebrate pests. In the present study, the effects of four members of macrolides; abamectin (ABM), emamectin benzoate (EMB), spinosad (SPI) and spinetoram (SPIT), on Meloidogyne incognita were investigated under in vitro and in vivo conditions. All compounds reduced egg hatching and led to high mortality of the nematode second-stage juveniles (J2). ABM showed the maximum rate of egg hatching inhibition and J2 mortality while SPIT recorded the minimum. All treatments reduced the number of galls, egg masses, eggs/egg mass in roots and J2 in the soil when compared to the control. Based on the 10 folds of the 24 h-LC50 values of J2 mortality in vitro, EMB and ABM exhibited higher percent reduction in galls (79.68 and 71.45%), egg masses (75.19 and 70.54%), eggs/egg mass (60.49 and 40.91%) and J2 in the soil (90.31 and 86.54%), respectively, compared to SPI and SPIT. Significant increase in tomato shoot height occurred in all biopesticides (10 folds) and SPIT (20 folds). SPI at 10 folds of the 24 h-LC50 values of J2 mortality in vitro, significantly increased root length while ABM at 50 folds and SPIT at 20 folds decreased root length by 5.15% and 5.88%, respectively, compared to the untreated inoculated plants. In all treatments, the dry shoot and root weights increased, compared to the untreated control. Our findings suggest that these macrolides have the ability to regulate nematode population densities and may be an alternative to classical nematicides.

scholarly journals Susceptibility of six tomato cultivars to the root-knot nematode, Meloidogyne incognita

2007 ◽  
Vol 25 (1) ◽  
pp. 73 ◽  
Author(s):  
Sunil K. Singh ◽  
Uma R. Khurma
Keyword(s):  
Meloidogyne Incognita ◽  
Root Knot Nematode ◽  
Inoculum Level ◽  
Root Knot Nematodes ◽  
Egg Masses ◽  
Tomato Cultivars

Six tomato cultivars Moneymaker, Beefsteak, Roma, Summertaste, Mini Roma and Smallfry were tested for their susceptibility to root- knot nematodes at inoculum levels of 200, 400, 600 Juveniles (J2) per pot. All were found to be susceptible to varying degrees as egg masses were present in all with Moneymaker and Roma being the most susceptible and Mini Roma, the least susceptible. The inoculum levels had a significant effect (p<0.05) on the number of galls and plant weights. The gall numbers and plant weights was negatively correlated, with the highest gall numbers and lowest plant weights recorded at the highest inoculum level in all cultivars except in Mini Roma in which there was little variation in gall numbers and plant weights.

scholarly journals A Technique for Screening Grape Germplasm for Resistance to Meloidogyne incognita

Plant Disease ◽  
2001 ◽  
Vol 85 (10) ◽  
pp. 1052-1054 ◽  
Author(s):  
P. M. Cousins ◽  
M. A. Walker
Keyword(s):  
Vitis Vinifera ◽  
Meloidogyne Incognita ◽  
Nematode Resistance ◽  
Egg Mass ◽  
Root Knot Nematode ◽  
Egg Masses ◽  
Nematode Eggs ◽  
Highly Correlated

A technique to evaluate the root-knot nematode resistance of grape seedlings was developed. Seedlings of rootstock crosses and nematode-susceptible Vitis vinifera cvs. Colombard and Carignane were inoculated with Meloidogyne incognita juveniles. Reproduction of nematodes on individual plants was measured by counting the number of egg masses stained with eosin and the number of eggs present. Egg mass counts were highly correlated with egg counts. Resistant and susceptible cultivars could be clearly distinguished by the number of egg masses produced on vegetatively propagated cuttings. It is concluded that egg mass counting can substitute for the more laborious and time-consuming methods of counting nematode eggs or juveniles in the evaluation of root-knot nematode resistance in Vitis.

scholarly journals Evaluation of Efficacy of Paecilomyces Lilacinus as Biological Control Agent of Meloidogyne Incognita Attacking Tomato

2009 ◽  
Vol 49 (4) ◽  
pp. 337-340 ◽  
Author(s):  
Elvira Oclarit ◽  
Christian Cumagun
Keyword(s):  
Biological Control ◽  
Meloidogyne Incognita ◽  
Biological Control Agent ◽  
Control Agent ◽  
Paecilomyces Lilacinus ◽  
Egg Mass ◽  
Root Weight ◽  
Egg Masses ◽  
Root Sample ◽  
Gall Index

Evaluation of Efficacy of Paecilomyces Lilacinus as Biological Control Agent of Meloidogyne Incognita Attacking Tomato The efficacy of Paecilomyces lilacinus strain UP1 as biological control agent of Meloidogyne incognita attacking tomato was evaluated under screenhouse condition pot experiments. P. lilacinus was formulated on rice substrate in powder form. Root weight, gall index rating, number of galls, egg masses and nematodes per one gram root sample were determined and per cent reduction in gall number was computed. Root weight and gall index ratings were significantly higher in untreated plants than those with P. lilacinus and with the commercial fungicide Nemacur. Number of galls, nematodes and egg masses per one gram root sample were significantly reduced by the application of P. lilacinus at all levels and this was comparable with Nemacur. However, egg mass count in plants treated with the lowest concentration of the biocontrol agent was not significantly different from the uninoculated control. Per cent reduction in gall number was the highest at treatment with 7.92 × 106 spores per ml of P. lilacinus.

scholarly journals Application of Biogas Digestate with Rice Straw Mitigates Nitrate Leaching Potential and Suppresses Root-Knot Nematode (Meloidogyne incognita)

Agronomy ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 227 ◽  
Author(s):  
Yuexi Wang ◽  
Seiya Chikamatsu ◽  
Tuya Gegen ◽  
Kozue Sawada ◽  
Koki Toyota ◽  
...  
Keyword(s):  
Rice Straw ◽  
Nitrate Leaching ◽  
Meloidogyne Incognita ◽  
Application Rate ◽  
Pig Manure ◽  
Test Plant ◽  
Root Knot Nematode ◽  
Root Knot Nematodes ◽  
Leaching Potential ◽  
Biogas Digestate

This study investigated the effects of biogas digestate application to soil with rice straw on nitrate leaching potential and nematicidal activity toward root-knot nematodes Meloidogyne incognita. The following seven treatments were set up: (i) control (CONT); (ii) chemical fertilizer (CF); (iii) wet biogas digestate derived from pig manure (WBD); (iv) and (v) dry biogas digestate derived from a mixture of pig manure and rice straw at an initial C/N ratio of 20 and 30 (DBD20 and DBD30); (vi) and (vii) DBD20 mixed with rice straw to adjust the C/N ratio to 16 (Mix1) and 30 (Mix2), respectively. The application rate of CF and digestates was adjusted to 200 mg N kg−1 soil based on the inorganic ammonium nitrogen contents. Nitrate contents readily increased in all the treatments with incubation, except for Mix2, and those at day 90 were decreased with increasing initial labile C contents. Garden balsam was grown as a test plant for root-knot nematodes using the soils at day 90 and the results showed that the gall index was significantly lower in Mix2 and Mix1 than in CF. These results suggest that dry digestate mixed with rice straw might have potential for lower nitrate leaching and nematicidal properties.

Identification of common bean (Phaseolus vulgaris) genotypes having resistance against root knot nematode Meloidogyne incognita

2015 ◽  
Vol 38 (5) ◽  
Author(s):  
Refik Bozbuga ◽  
H. Yildiz Dasgan ◽  
Yelderem Akhoundnejad ◽  
Mustafa Imren ◽  
Halil Toktay ◽  
...  
Keyword(s):  
Common Bean ◽  
Meloidogyne Incognita ◽  
Resistance Index ◽  
Egg Mass ◽  
Yield Losses ◽  
Fresh Weight ◽  
Root Knot Nematode ◽  
Resistance Response ◽  
Parental Material ◽  
Moderately Resistant

Root knot nematodes (<italic>Meloidogyne</italic> spp.) cause immense yield losses in crops throughout the world. Use of resistant germplasms of plants limits the root knot nematode damages. In this study, 87 common bean (<italic>Phaseoulus vulgaris</italic> L.) genotypes were screened against the root knot nematode, <italic>Meloidogyne incognita</italic> to determine the resistance response under growth chamber conditions in Turkey. <italic>P. vulgaris</italic> genotypes were evaluated based on resistance index (RI); root galling severity and nematode egg mass production on a 1-9 scale. The nematode negatively influenced the growth (fresh weight) of bean genotypes. At the completion of the study, 13 bean genotypes were found as immune (Sehirali), highly resistant (TR42164, Seleksiyon 5, Seker Fasulye, Fas-Agadir-Suk-1) and moderately resistant (Acik Badem, TR68587, TR43477, TR53827, TR28018, Gülnar-3, Siyah Fasulye, Kibris Amerikan) against <italic>M. incognita</italic> thus suggesting the use of such genotypes in breeding studies as a parental material to develop the root knot nematode resistant cultivars.

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 Estimation of avoidable losses caused by Meloidogyne incognita infecting cucumber in poly-house

2021 ◽  
Vol 2 (1) ◽  
pp. 35-40
Author(s):  
Shakti Singh Bhati ◽  
B. L. Baheti
Keyword(s):  
Meloidogyne Incognita ◽  
Agricultural Land ◽  
Egg Mass ◽  
Root Knot Nematode ◽  
Cucumis Sativus L ◽  
Continuous Increase ◽  
Daily Diet ◽  
Protected Cultivation ◽  
Meloidogyne Spp ◽  
Present Trial

Cucumber (Cucumis sativus L.) is a high nutritious and mineral-rich vegetable, which occupies a prominent place as a salad and vegeta-ble. It is being used in many ways in the daily diet of humans and widely cultivated worldwide. The decrease of agricultural land, ad-verse environmental conditions and continuous increase of popula-tion, the demand of nutritious food is a matter of great concern to the world. Protected cultivation is a very effective tool to solve this problem because in this cultivation the productivity of crops is very high as compared to open field conditions. High value crops suc-cessfully grown in protected cultivation, specially vegetables (cu-cumber, tomato, Capsicum etc.) which are highly susceptible to the numerous pests and pathogens, including phyto-parasitic nema-todes (specially root-knot nematode, Meloidogyne spp.). With this view, present trial was taken to estimate the avoidable losses caused by Meloidogyne incognita infecting cucumber in poly-house situated on farmer’s field with the application of phorate at 2 kg a.i. ha-1 over check. Results exhibited that application of chemical treatment significantly reduced number of galls per 5 g roots, egg masses per 5 g roots, eggs & juveniles per egg mass and final nema-tode population 79.03, 81.10, 30.91 and 56.54%, respectively. Avoidable yield losses were recorded to the tune of 66.84% on cu-cumber by M. incognita in poly-house.

scholarly journals Heritability of Root-knot Nematode (Meloidogyne spp.) Resistance in Sweetpotatoes

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 622a-622 ◽  
Author(s):  
W. R. Maluf ◽  
S. M. Azevedo ◽  
V.P. Campos
Keyword(s):  
Meloidogyne Incognita ◽  
Meloidogyne Javanica ◽  
Broad Sense Heritability ◽  
Root Knot Nematode ◽  
Egg Masses ◽  
Substrate Removal ◽  
Meloidogyne Spp ◽  
Diverse Origin ◽  
Race 2 ◽  
Resistant Genotypes

Heritabilities for resistance to root knot nematodes (Meloidogyne javanica and Meloidogyne incognita races 1, 2, 3, and 4) were studied in a population of 226 sweetpotato clones of diverse origin. For each nematode isolate tested, 128-cell speedling trays were filled with previously inoculated substrate (30000 eggs/1000 mL substrate). Sweetpotato clones suitably tagged and identified were randomly planted in the cells (one plant/cell), with a total of four plants per clone per isolate. Ninety days after inoculation, sweetpotato plants had their roots washed for substrate removal, and treated with 150 mg·L–1 Phloxine B to stain nematode egg masses. The number of egg masses per root was recorded, and plants were accordingly assigned scores from 0 (highly resistant) to 5 (highly susceptible). Broad-sense heritability estimates were 0.87, 0.91, 0.81, 0.95, and 0.93 respectively for resistance to M. javanica and races 1, 2, 3, and 4 of M. incognita. The frequencies of resistant genotypes were higher for M. javanica and lower for M. incognita race 2. Genotypic correlations (rG) among the resistances to the various Meloidogyne isolates utilized were weak, ranging from 0.11 to 0.57, suggesting independent genetic controls. Clones could be selected, however, with high levels of resistance to all nematode isolates tested. (This work was supported by CNPq, CAPES, FAPEMIG, and FAEPE/UFLA.)

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