• Animal Systematics, Evolution and Diversity
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• v.34 no.4
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• pp.194-198
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• 2018

The genus Prionchulus Cobb, 1916 represents a group of predaceous nematodes belonging to the family Mononchidae Chitwood, 1937, and is found worldwide. However, only five species have been reported thus far from Korea. Prionchulus oleksandri Winiszewska and Susulovsky, 2003 is reported for the first time from Korea, from sediments collected from the Nakdong River. This species is distinguished from other Prionchulus species by its truncated lip region with small cephalic papillae and refringens vaginae. In this study, morphological characters(detailed morphometrics) of P. oleksandri are described and illustrated using optical microscopy. DNA barcode sequence information (the D2-D3 region of 28S rDNA, 18S rDNA, and internal transcribed spacer rDNA) is also provided for the molecular identification of the species.

• Journal of Species Research
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• v.10 no.4
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• pp.405-411
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• 2021

The genus Acrobeloides(Cobb, 1924) Thorne, 1937 are bacterial feeders and are one of the most abundant and widely distributed nematode groups in various terrestrial environments. Based on morphological and morphometric analyses, we found two Acrobeloides species reported in Korea for the first time: A. bodenheimeri (Steiner, 1936) Thorne, 1937 and A. tricornis (Throne, 1925) Thorne, 1937. These species exhibit morphological characters concordant with typical features of the genus Acrobeloides, such as a fusiform pharyngeal corpus with swollen metacorpus and lateral incisures extending to the tail terminus. However, A. bodenheimeri is distinguished from other acrobeloids by having its low and rounded labial probolae, distinct post-uterine sac and five lateral incisures. Acrobeloides tricornis is distinguished from its congeners by the following characteristics: its high labial probolae with acuate termini, inconspicuous post-uterine sac and five lateral incisures. Morphological characters and their measurements, and illustrations of A. bodenheimeri and A. tricornis are described in this study.

• Journal of the Korean Wood Science and Technology
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• v.37 no.3
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• pp.200-207
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• 2009

As an effort to utilize the pine woods damaged by pine wilt disease, this study analyzed the density of pine wood nematode and compressive strength of damaged trees treated through soaking and fumigating. The density of nematode in Pinus densiflora and Pinus thunbergii woods soaked in wood vinegar and nematicide, and in seawater reduced greatly in 21 days and in 30 days, respectively. When reextracted nematode was injected artificially into healthy trees, infection was not observed after the lapse of six months, and the mean density of Pinus densiflora and Pinus thunbergii was $0.47g/cm^3$ and $0.54g/cm^3$, respectively, and their compressive strengths were $304kgf/cm^2$ and $363kgf/cm^2$, respectively. As to change in the density of pine wood nematode after fumigating, pine wood nematode was detected until the third month in both species, and those detected afterwards were found to be similar nematodes. After 24 months, the mean densities of Pinus densiflora and Pinus thunbergii were $0.54g/cm^3$ and $0.52g/cm^3$, respectively, and their compressive strengths were $353kgf/cm^2$ and $370kgf/cm^2$, respectively.

• Korean journal of applied entomology
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• v.46 no.1 s.145
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• pp.147-151
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• 2007

Laboratory tests were conducted to determine the susceptibility of the alfalfa weevil, Hypera postica to Korean entomopathogenic nematodes, Steinernema carpocapsae GSN1 strain (ScG), S. glaseri Dongrae strain (SgD), Heterorhabditis bacteriophora Hamyang strain (HbH), and Heterorhabditis sp. Gyeongsan strain (HeG) at the petri dish assay. The larval mortality of H. postica was significantly different depending on nematode species and treatment concentration. SgD and HeG strain were more effective against H. postica larva than ScG and HbH strain. When SgD and HeG strain were treated with the rate of >20 infective juveniles (ijs) per alfalfa weevil larva, mortality was ca. 77.5-100% at the late instars of H. postica in 3 days. The number of established nematode was significantly different depending on nematode species, whereas number of progeny was not significantly different. The mean number of established us of SgD strain in a host was the highest at 80 ijs by 30.2. The highest progeny number of HeG strain was 2,671.5 with 80 ijs. All nematode strains were not parasitic entirely to H. postica adults. These results show that alfalfa weevil late larva is highly susceptible to Korean entomopathogenic nematodes in the laboratory.

• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.335-343
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• 2006

Five strains of Korean entomopathogenic nematodes(EPN), steinernematids and heterorhabditids(Steinernama carpocapsae GSN1, Steinernema sp. GSNUS-10, Steinernama sp. GSNUS-14, Heterorhabditis bacteriophora Hamyang, Heterorhabditis sp. GSNUH-1) were evaluated and tried in petri dish, pot, and vegetable greenhouses for environmentally friendly control of beet armyworm, Spodoptera exigua. $LC_{50}$ values of five EPN strains against beet armyworm was different depending on nematode strain and beet armyworm instar. $LC_{50}$ value of Steinernema carpocapse GSN1(GSN1) was 3.8-5.1 infective juveniles(Ijs) in 2nd to 4th instars of beet armyworm. Pathogenicity of five EPN strains against beet armyworm different in nematode strain, concentration, application times, and vegetable species in pot and greenhouse. Steinernema spp. was more effective than Heterorhabditis spp. against beet armyworm. Two or three times of applications of EPN were found to be effective regardless of nematode strain and concentration in pot and greenhouse. ENP showed different reactions on vegetable species. Efficacy of EPN was higher on Chinese cabbage than that on cabbage and kale. GSN1 was one of the most effective nematodes and 100,000 infective juveniles per $m^2$(720,000 Ijs/$7.2m^2=1{\times}10^9$Ijs/ha) resulted in higher mortality in greenhouse.

• Animal Systematics, Evolution and Diversity
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• v.36 no.3
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• pp.251-257
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• 2020

The genus Plectus Bastian, 1865 represents a group of free-living freshwater nematodes belonging to the family Plectidae Örley, 1880. However, only one species has been reported thus far from Korea. Plectus aquatilis Andrássy, 1985 and Plectus cirratus Bastian, 1865 are reported for the first time from Korea, from sediments collected from the Nakdong River. Plectus aquatilis is distinguished from other Plectus species by its three longitudinal alae in the lateral field, thin and directed cephalic setae, continuous lip region (head not set-off), and rectangular shaped tail. Plectus cirratus is distinguished from other Plectus species by its large body, two longitudinal alae in the lateral field, larger stoma, and longer tail. Morphological characters and measurements of the specimens generally agree with the original descriptions of Plectus species. Here, the morphological characters (detailed morphometrics) of two species in the genus Plectus are fully redescribed and illustrated using optical microscopy. DNA barcode sequence information from the 18S rDNA gene is also provided for molecular species identification and compared with sequences from other Plectus species available on GenBank.

• KSBB Journal
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• v.17 no.3
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• pp.276-282
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• 2002

Symbiotic bacteria with highly effective insecticidal activities were isolated and compared with their physiological characteristics from seven species of entomopathogenic nematodes belong to Steinernamatidae and Heterorhabditidae sp., and three of them were identified as Xenorhabdus nematophilus. Culture characteristics, insecticidal activities, pretense activities and fatty acid contents of various symbiotic bactierial isolates were also examined. In the case of cell growth and insecticidal activity, XR-PC and XR-MK were superior to other species when cultured in vitro. The insecticidal activity were highest at the early exponential growth phase, and gradually decreased with time. The protease activity of XR-DR was remarkable compared to other species. In the case of HE-HY, however the pretense activity increased in parallel with cell growth. Interestingly, the fatty acid patterns of Xenorhabdus nematophilus isolated from different emtomopathogenic nematode, showed remarkable differences in their contents of 12:0, 14:0, 16:1 cia 5 and 17:0 cyclo and hydroxy and branch factty acids were varied from 2% to 15% among total fatty acid contents.

• Animal cells and systems
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• v.8 no.4
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• pp.235-245
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• 2004

Numerous specimens of adults and juveniles of Draconema japonicum Kito, 1976 have been found in intertidal and subtidal sediments and various algae around coast of South Korea. Draconema japonicum is recognized by the following characteristics: having an elongated loop-shaped amphideal fovea in male and horseshoe-shaped amphideal fovea in female, two pairs of uniformly tapered sublateral anal setae and two pairs of unevenly tapered subventral anal setae in male, eight to ten pairs in male and 13 to 15 pairs in female of posterior sublateral adhesion tubes, and five to six pairs of somatic setae on non-striated tail region. Scanning electron photomicrographs of the species are presented with a detailed morphological description and a key to the species of the genus Draconema Cobb, 1913. This is the first discovery of D. japonicum outside the Japanese waters.

• Korean journal of applied entomology
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• v.42 no.2
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• pp.91-100
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• 2003

Helicotylenchus clarkei Sher, 1966 and Rotylenchus usitatus Van den Berg et Heyns, 1974 were newly found in Korea from medicinal plant collection field in Gyeongbuk Agricultural Technology Administration, Daegu, Korea. So far, 9 species of Rotylechus (R. usitatus) and 8 species of Helicotylenchus (H. belli, H. cavenessi, H. clarkei, H. digonicus, H. dihystera, H. erythrinae, H. paraplatyarus, H. pseudorobustus) are recorded in Korea.

• Korean journal of applied entomology
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• v.31 no.4
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• pp.396-415
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• 1992

To investigate identification of species distribution state, population density of plant parasitic nematodes and damaged state by parasitism of nematodes with soil samples taken from major cultivating area of medicinal herbs in Kyungbuk districts are summarized as follow; total species belonging to genera in families were identified from 43 different medicinal herbs. The dominant nematode species on medicinal herbs was Meloidogyne hapla by 55.6% of field infection. Damaged state by parasitizm of Root-knot nematode, M. hapla, M. incognita are severed 15 medical plant except P. japonica, infected field were in 54.5~88.0%, and highered in population densities of 2nd larvae, Gall, Egg sac. Percentage of yield-decrease were 57.8% in A. gigas, 49.1% in P.japonica. Lighten effect of M. spp. by cropping system were lowered in population density in Rice+Paeony than Paeony+Paeony in paddy field, and also lowered in Sesame+Paeony or one year fallowing after harvest Paeony than Red pepper+Pseony, Paeony+Paeony in upland field.