• The Korean Journal of Soil Zoology
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• v.6 no.1_2
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• pp.33-36
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• 2001

This study was carried out to screen 11 peony varieties collected for resistance to northern root-knot nematode, Meloidogyne hapla. The larval population of Meloidogyne halpa to the Uisongjakyak, Taebaekjakyak, Doseo, EP368, EP512 peony were detected high denisties with individuals of 98-173 per 300 ml soil, but Sabeol, Yongsu, Kimchon, Pl23 peony showed low number of larvar with 21-60. The root rot were lowered in Yongsu, Kimchon peony than Uisongjakyak, Taebaekjakyak, EP368, EP512. It seems to involved with densities of 2nd juvernile population in that rot rate of root was increased as increase of 2nd stage larvae. Two peony, Uisongjakyak, Taebaekjakyak were susceptable to M. hapla with high egg mass formation which showed 49,28 in each root. And Yongsu, Doseo, EP368, EP512 were Mid resistance with 1-15 egg mass of each root. Whereas Sabeol, Kimchon, Pl23, EP337, EP425 were found to be resistant to M, hapla with few egg mass formation of 4-7 each root.

• The Plant Pathology Journal
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• v.33 no.4
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• pp.410-423
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• 2017

Pathological interrelations of two soil-borne diseases in cucurbits (watermelon, oriental melon, shintosa and cucumber) caused by Fusarium isolates (FI) and the root-knot nematode (RKN), Meloidogyne incognita were characterized by the fusarium disease severity index (DI), RKN gall index (GI) and eggmass index (EI) in inoculation tests using FI and RKN. Virulence of FI as determined by DI at 4 weeks after inoculation was mostly in the higher order of Fusarium proliferatum F6, F5 and Fusarium oxysporum f. sp. melonis or Fusarium oxysporum f. sp. niveum with no significant differential interactions among the cucurbits and RKN co-infection. Significant increases of DI due to RKN coinfection were noticed in watermelon and oriental melon infected with F. proliferatum isolates, suggesting the DI increase due to RKN coinfection may depend upon the virulence of FI relative to aggressiveness of RKN on the cucurbits. For the coinfection of FI and RKN, GI and EI were mostly reduced logarithmically with the increase of DI, largely more in EI than GI, in all cucurbits except for shintosa. Microscopic examination of the root tissues showed histopathological features characteristic to infection types; formation of fungal hyphae and/or spores and plant defense structures (tyloses and mucilage) in variable degrees and formation of giant cells at variable developmental stages and with variable cytoplasmic depletion or degeneration which were visualized in relations with the values of DI, GI and EI. These findings will be helpful to develop control strategies of the soil-borne disease complex based on their pathological characteristics.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.471-478
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• 2018

The purpose of this study was to investigate effects of reusable organic wastes, on soil organisms and chemical properties. Bone meal, de-oiled cake, and oyster shell were applied and abundances of soil organisms were measured at 3 and 15 months, after treatment in soil under sawleaf zelkova cultivation. Soil organisms are affected, by the quality of applied organic wastes. Abundance of microorganisms was higher in oyster shell treated soils than in untreated soils, suggesting that soil pH is a driving force, altering abundance and structure of the microbial community. Increase in abundance of bacterivorous nematodes was observed under treatment with bone meal and de-oiled cake, but there was slight change in abundance of fungivorous and herbivorous nematodes. Abundance of herbivorous nematode was positively correlated with plant growth, at 15 months after treatment. Response of microarthropods in the Collembola and Oribatida was not apparent. Abundances of primary consumers were not significantly correlated with microorganisms. This study suggested that organic waste influences soil organisms primarily by altering soil chemical properties and bottom-up effects may not occur in trophic reactions.

• The Korean Journal of Soil Zoology
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• v.8 no.1_2
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• pp.23-26
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• 2003

A neem based product, Suneem-G (granules) alone as well as in combination with urea was tested against root-knot nematode, Meloidogyne incognita, on okra (Abelmoschus esculentum) in clay pots of 20-cm-diameter, containing 2 kg sterilized soil, inoculated with 2,000 freshly hatched second stage juveniles (J$_2$) of M. incognita. Application of different dosages of Suneem-G with or without urea significantly reduced nematode population and incidence of galling on okra roots and increased vegetative plant growth compared with the untreated control. Suneem-G with urea was the most effective and its effect increased with the increase of dosage. Suneem-G 6 g＋urea 25 g per pot gave maximum plant growth and root gall reduction, as plants shoot and root lengths were increased by 84 and 58% and root galling was reduced by 58%, respectively. The lowest dosage of Suneem-G alone, 2 g per pot increased shoot and root lengths of plants by 25.7 and 17%, respectively, and reduced root galling by 24%. The lowest effect was recorded in the pots treated with 25 g urea alone; shoot and root lengths were increased and root galling was decreased by 14% each.

• Korean Journal of Microbiology
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• v.21 no.3
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• pp.127-134
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• 1983

42 strains belonging to the genus Arthrobotrys and 17 strains belonging to the genus Monacrosporium, were isolated from soil specimens collected from the various localities in South Korea. 4 species of Arthrobotry and 2 species of Monacrosporium, which are unrecorded in Korea, were identified according to the Harrd and Cooke classification key, respectively. The species identified are as follows ; A.conoides, A. oligospora, A. musiformis, A. oviformis, M. crystosporum nd M. salinum.

• Journal of Ecology and Environment
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• v.33 no.4
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• pp.317-323
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• 2010

Nutrient availability is a critical component of agroecosystems, and is relevant to both above- and below- ground interactions. The principal objective of this study was to determine how the cessation of fertilization affects the communities of weeds and soil organisms in a corn/wheat field. Changes in dominant weed species, substrate-induced respiration, and the population density of nematodes and microarthropods were evaluated. Microbial substrate-induced respiration (SIR) and the population density of microarthropods decreased following the cessation of fertilization and were partly correlated with the aboveground weed biomass. The cessation of organic fertilizer application but continuing application of inorganic fertilizer reduced the population density of nematodes. In response to the cessation of fertilization, weed communities were dominated by species with little dependency on fertilization. Amaranthus retroflexus was identified as the most dominant species in the corn field; however, it was replaced by Digitaria ciliaris after the cessation of fertilization. In the wheat field, the cessation of fertilization led to a rapid reduction in the biomass of most weeds, except for Vicia angustifolia, supposedly as the result of symbiotic nitrogen fixation. Additionally, the fact that weed biomass was partially correlated with SIR or the population density of microarthropods may reflect a mutual feedback between soil organisms and weeds. The results indicate that the cessation of fertilization alters communities of weeds and soil organisms through changes in weed biomass and interactions with symbiotic microorganisms.

• Korean journal of applied entomology
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• v.37 no.2
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• pp.123-125
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• 1998

In peony fields located in Uisong and Yeongcheon distribution of Meloidogyne hapla was examined. Of 131 fields examined, M. hapla was isolated from 102 fields. In 57.8% of the infested fields, M. hapla density was higher 31 larvae1300 ml soil, the larval density isolated from upland fields were higher than those from paddy fields. Sandy loam soil harbored higher number of larvae than clay soil. Physio-chemical properties of soil might affect nematode population: High larval density was detected from those fields with low contents of OM, K+ and low pH. Fields infested with high larval densities required more lime than those with low or non infested fields.

• Korean journal of applied entomology
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• v.58 no.1
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• pp.9-13
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• 2019

Nematode-trapping fungi use various specialized traps to capture nematodes. A fungus that can capture nematodes in three dimensional adhesive networks was isolated from the soil around the root of Cucumis melo L. (Oriental melon) in Seongju, Korea. The conidiophores were found to be septate, hyaline, erect and $290-528(342.8){\mu}m$ high. It produces obovoid shape and 1-3 septate (commonly 2-septate) conidia with a size of $30.5{\times}20.3{\mu}m$. Molecular analysis of 5.8 S rDNA displayed 99% similarity to Arthrobotrys sinensis. On the basis of morphological, morphometric and molecular studies, the fungus was identified as A. sinensis. It is the first report in Korea which can be one of biological control resource of plant-parasitic nematode.

• Research in Plant Disease
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• v.25 no.3
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• pp.124-130
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• 2019

The study was conducted to investigate the infestation and distribution of plant-parasitic nematodes on Chinese yam (Dioscorea batatas) in Andong, Korea. Root-knot nematodes, Meloidogyne incognita was the most prevalent nematode species which is found from 43 yam fields (81.1%) with high population densities (average of 450 juveniles/$300cm^3$). Other nematodes, root-lesion nematode (Pratylenchus spp.) and pin nematode (Paratylenchus spp.) were less problematic. Density of juveniles (J2) of M. incognita was $10\;J2/300cm^3$ by August, then increased to 274 in September and 624 in October. The highest J2 density was found at the soil depth between 40 and 50 cm ($1,840\;J2/300cm^3$). M. incognita was able to infest yam tuber down to a depth of 70 cm and developed galls outside and brown spots inside. The highest number of females were found at 40-50 cm (79 females/10 cm piece) tuber from the top.

• The Korean Journal of Mycology
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• v.47 no.4
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• pp.291-301
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• 2019

Nematophagous fungi can capture, kill, and digest nematodes using a specific capturing organ. Of the nematophagous fungi, while Arthrobotrys flagrans and A. superba have been described previously, certain characteristics have not been described. For a detailed description of the two nematophagous fungi, the fungi were isolated from soil samples and produced in a pure culture. Morphological characteristics, such as predatory ability (according to the nematode species), shape, and size of predatory organ, conidia, and chlamydospore were investigated and they were used for identification of the fungal isolates along with molecular phylogenetic analysis. Furthermore, this study provides the classification key for 21 nematophagous species.