• The Korean Journal of Soil Zoology
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• v.8 no.1_2
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• pp.27-31
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• 2003

This study has been conducted to assess and analyze the damage of Codonopsis lanceolata by differential inoculation levels of Meloidogyne hapla in pot and plot. As the density of M. hapla increased, early growth of C. lanceolata was inhibited 60% in vine and 54% in root. However, growth of C. lanceolata was not remarkably different by density of M. hapla in the plot test. This result may be attribute to low density of M. hapla in the plot.

• The Plant Pathology Journal
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• v.36 no.3
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• pp.297-302
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• 2020

Root-knot nematodes (Meloidogyne spp.) are the most destructive group of plant-parasitic nematodes. Plants infected by Meloidogyne spp. develop above-ground symptoms, stunting, yellowing, nutrient deficiencies, and gall formations with typical hook-shaped root tips. Infected plants experience yield losses. During 2018-2019 survey, leaf chlorosis rice plants were found in 206 fields of 67 counties in Guangxi, China, around 30 days after transplanting. Galls and hooked tips on the roots and pear-shaped females were observed. About 32.04% of fields were infested with the nematode. The nematodes were identified as Meloidogyne graminicola base on morphological and molecular analysis. To the best of our knowledge, this is the first report of M. graminicola on rice plants in Guangxi, China. The results of this study urge the discovery of resistant cultivars and the development of management strategies.

• The Plant Pathology Journal
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• v.30 no.4
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• pp.450-455
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• 2014

This study sought to control the root-knot nematode (RKN) Meloidogyne incognita using benign organo-chemicals. Second-stage juveniles (J2) of RKN were exposed to dilutions (1.0%, 0.5%, 0.2%, and 0.1%) of acetic acid (AA), lactic acid (LA), and their mixtures (MX). The nematode bodies were disrupted severely and moderately by vacuolations in 0.5% of MX and single organic acids, respectively, suggesting toxicity of MX may be higher than AA and LA. The mortality of J2 was 100% at all concentrations of AA and MX and only at 1.0% and 0.5% of LA, which lowered slightly at 0.2% and greatly at 0.1% of LA. This suggests the nematicidal activity of MX may be mostly derived from AA together with supplementary LA toxicity. MX was applied to chili pepper plants inoculated with about 1,000 J2, for which root-knot gall formations and plant growths were examined 4 weeks after inoculation. The root gall formation was completely inhibited by 0.5% MX and standard and double concentrations of fosthiazate; and inhibited 92.9% and 57.1% by 0.2% and 0.1% MX, respectively. Shoot height, shoot weight, and root weight were not significantly ($P{\leq}0.05$) different among all treatments and the untreated and non-inoculated controls. All of these results suggest that the mixture of the organic acids may have a potential to be developed as an eco-friendly nematode control agent that needs to be supported by the more nematode control experiments in fields.

• Korean journal of applied entomology
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• v.27 no.1
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• pp.1-5
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• 1988

This study was carried out to find out the possibility of suppressing the root-knot nematodes (Meloidogyne spp.) of vegetable crops in vinyl house by soil solarization between crop seasons at Suweon in August, 1986. Soils in vinyl house were sterilized by polyethylene film of 0.03 mm thick with and without inner tunnel within a house(single and double layer solarization), and soil temperatures and nematode densities at 5, 15 and 30cm soil depth were recorded. Rootknot nematodes in soil contained in a vinyl bag were completely killed within 48hr at $40^{\circ}C$ in an incubator. With double layer treatment, the highest temperatures were $48.7^{\circ}C$ at 15cm and $45.2^{\circ}C$ at 30cm soil depth when outdoor temperature was $30^{\circ}C$, and the lethal temperature above $40^{\circ}C$ was recorded for 17 days with 7hr per day at 5cm soil depth from Aug 1 to Aug 31. Due to the increased temperature, root-knot nematode densitiy was suprressed 96,74 and 54% with sigle layer solarization and 100,99 and 98% with double layer solarization at 5,15 and 30cm soil depth, respectively. It is concluded that double layer solarization during hot summer will provide a sufficient level of suppresson on root-knot nematodes remnant in the soil of vegetable crops in vinyl house.

• Korean Journal of Organic Agriculture
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• v.30 no.1
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• pp.103-118
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• 2022

Photorhabdus is a bacterial symbiont of entomopathogenic nematodes of the genus Heterorhabditis in the family Heterorhabditidae. Photorhabdus is known to have nematicidal activity in addition to insecticidal activity. P. temperata isolated from Korean indigenous H. megidis Gwangju strain also produced high control efficacy against root-knot nematode Meloidogyne incognita and root-lesion nematode Pratylenchus penetrans. P. temperata has drawn interest as a potential bionematicide for the control of root-knot nematodes thereby. For the registration as an organic agricultural material, the toxicity of P. temperata was assessed by the acute toxicity test in carp (Cyprinus carpio) and acute oral and dermal toxicity tests in Sprague-Dawley rat (Rattus norvegicus) in compliance with the guidelines of the Rural Development Administration (RDA). In the acute toxicity test in fish, neither lethality nor abnormal responses of carp were observed. Body length and weight of carp and changes in DO concentrations and pH values were not significantly different between the treated group and the untreated control. In the acute oral and dermal toxicity tests, clinical signs, abnormal behavior, mortality, and pathological findings were not observed in all the experimental rats. The weight increment of all rats was normal. Acute toxicity results of P. temperata in fish and rats belonged to categories III, IV, and IV of RDA, respectively. Toxicity results of the present study indicated that P. temperata could be a safe and promising bionematicide against root-knot nematodes and root lesion nematode.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.401-408
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• 2016

The present study described the isolation of 2-methylbutyric acid (2-MBA) produced from Bacillus pumilus L1, to subsequently investigate its nematicidal activity for the control of the root-knot nematode. The results showed that 2-MBA could be purified by chromatographic techniques and was identified using nuclear magnetic resonance and liquid chromatography-mass spectrometry. Crude extract and partially purified compounds had a significant effect on the inhibition of egg hatchability and second-stage juvenile (J2) mortality. A dose-dependent effect of 2-MBA was observed for J2 mortality and egg hatchability. Egg hatchability was 69.2%, 59.9%, 32.7%, and 0.0% at 125, 250, 500, and $1000{\mu}g\;mL^{-1}$ of 2-MBA after 4 d of incubation, respectively. Meanwhile, J2 mortality was in the range of 24.4%-100.0% after 2 d of incubation, depending on the concentrations of 2-MBA used. A pot experiment also demonstrated that treatment of B. pumilus L1 culture caused a significant reduction in the number of galls, egg masses, and J2 population than that of the tap water (TW) control. However, as the B. pumilus L1 culture concentration was decreased, the efficacy of nematode control by treatment of B. pumilus L1 culture was reduced compared to that of TW. B. pumilus L1 inoculation at different concentrations also promoted cucumber plant growth. Therefore, our study demonstrated the potential of 2-MBA from B. pumilus L1 as a biocontrol agent against the root-knot nematode and a plant growth promoter for cucumber plants.

• The Plant Pathology Journal
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• v.34 no.6
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• pp.544-554
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• 2018

Tomato (Solanum lycopersicum) production in Ghana is limited by the root-knot nematode (Meloidogyne incognita, and yield losses over 70% have been experienced in farmer fields. Major management strategies of the root-knot nematode (RKN), such as rotation and nematicide application, and crop rotation are either little efficient and harmful to environments, with high control cost, respectively. Therefore, this study aims to examine morphometric variations of RKN populations in Ghana, using principal component analysis (PCA), of which the information can be utilized for the development of tomato cultivars resistant to RKN. Ninety (90) second-stage juveniles (J2) and 16 adult males of M. incognita were morphometrically characterized. Six and five morphometric variables were measured for adult males and second-stage juveniles (J2) respectively. Morphological measurements showed differences among the adult males and second-stage juveniles (J2). A plot of PC1 and PC2 for M. incognita male populations showed clustering into three main groups. Populations from Asuosu and Afrancho (Group I) were more closely related compared to populations from Tuobodom and Vea (Group II). There was however a single nematode from Afrancho (AF4) that fell into Group III. Biplots for male populations indicate, body length, DEGO, greatest body width, and gubernaculum length serving as variables distinguishing Group 1 and Group 2 populations. These same groupings from the PCA were reflected in the dendogram generated using Agglomerative Hierarchical Clustering (AHC). This study provides the first report on morphometric characterisation of M. incognita male and juvenile populations in Ghana showing significant morphological variation.

• Horticultural Science & Technology
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• v.32 no.2
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• pp.217-226
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• 2014

Root-knot symptoms were found on a commercial tomato cultivar carrying Mi, a resistance gene to root-knot nematodes including Meloidogyne incognita, M. arenaria, and M. javanica in 2012 at Buyeo, Chungnam Province in Korea. The isolate was identified as M. incognita based on molecular analyses using two species-specific primer sets. Pathogenicity of the isolate on one susceptible and three resistant tomato cultivars to the root-knot nematodes was tested. The nematode isolate showed strong pathogenicity on all the tested cultivars at all tested incubation temperatures. In addition, resistance degree of 33 commercial tomato cultivars, 8 susceptible and 25 resistant cultivars to root-knot nematodes, was also tested. Plants were determined as resistant when they suppressed the nematode reproduction. All the cultivars demonstrated strong susceptibility to the nematode regardless of resistance of the tomato cultivars. To our knowledge, this is the first report on the occurrence of Mi infecting M. incognita isolate in Korea. On the other hand, to construct an efficient screening method for selecting resistant breeding source to the nematode isolate, root-knot development of M. incognita on four tomato cultivars according to several conditions such as inoculum concentration, plant growth stage, and incubation period after transplant was investigated. Reproduction of the nematode on all the tested cultivars according to inoculum concentration increased in a dose-dependent manner. Except for inoculum concentration, there was no significant difference in reproduction level of the cultivars according to the other tested conditions. On the basis of the results, we suggest an efficient screening method for new resistant tomato to the nematode isolate.

• The Plant Pathology Journal
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• v.35 no.1
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• pp.51-62
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• 2019

A great variable response was observed when PP-3 and PP-J encumbered with 116 populations of root knot nematode (RKN) at two different temperatures ($25{\pm}2^{\circ}C$ and $30{\pm}2^{\circ}C$) and concentrations ($10^4$ and $10^5$ spores/ml). The PCR reaction amplified intergenic region between cytochrome oxidase subunit II gene (COII) and large subunit of rRNA gene (lrRNA) of the mitochondrial genome of different RKN species. The primer C2F3 and 1108 identified M. incognita with the highest frequency (52.6%) followed by M. javanica (36.8%) and M. arenaria (10.5%). The sizes of PCR products were 1.7 kb for M. incognita and M. javanica populations while populations of M. arenaria produced 1.1 kb fragment. The digestion with Hinf I yielded three different fragment length patterns on 1.5 % agarose gel. From current research it is concluded that intra-Meloidogyne genetic variability exist in RKN populations which have better encumbrance with P. penetrans.

• Korean journal of applied entomology
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• v.21 no.3 s.52
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• pp.146-152
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• 1982

Survey on potato parasitic nematodes has been undertaken in order to find distribution of the nemic fauna. 41 soil samples were taken from potato fields in Gyeongbug, Gyeongnam and Gangweon provinces. Twenty four species belonging to 16 different genera were identified. Potato cyst nematode, Globodera rostochiensis was not found in the areas. Potato-rot nematode, Ditylenchus destructor and stem nematode, Ditylenchus dipsaci were found from several potato fields and population density high and showed damage to the crops. Root-lesion nematode, Pratylenchus minyus, Pratylenchus penetrans, Pratytenchus thornei and Pratylenchus vulnus were found and their population of these four species were high depending on the fields. Root-knot nematode, Meloidogyne hapla and Meloidogyne incognita were found. M. hapla was found only in Gangweon province and the population density was high. M. incognita was found at Milyang in Gyeongnam province. Spiral nematode, Heticotylenchus digonichus, Helicotylenchus dihystera, Helicotylenchus pseudorobustus, Rotylenchus orientalis and Rotylenchus pini were found. Aphelenchoides saprophilus, Criconemoides informis, Ditylenchus destructor, D. dipsaci, Helicotylenchus digonichus, H. dihystera, Hemicriconemoides intermedius, Meloidogyne hapla, Psilenchus hilarulus, Pratylenchus minyus, and Xiphinema americanum were first found from potato fields in Korea.