• The Plant Pathology Journal
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• v.26 no.2
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• pp.149-153
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• 2010

Biological and structural mechanisms of the nematode disease development in chili pepper caused by the root-knot nematode, Meloidogyne incognita, were investigated. Out of 39 chili pepper cultivars/lines tested, six were found resistant, while 33 were susceptible to M. incognita, of which a susceptible cultivar Chilseongcho and three resistant cultivar/lines CM334, 02G132 and 03G53 with different resistance degrees were selected for microscopic studies on the disease development. Gall formation was greatly reduced in the resistant cultivars/lines. Nematode penetration occurred both in the susceptible and resistant chili pepper roots; however, the penetration rates were significantly lowered in the three resistant peppers compared to the susceptible pepper cv. Chilseongcho. In the susceptible pepper, giant cells were extensively formed with no discernible necrosis around the nematode feeding sites. In the highly resistant pepper cultivar CM334, no giant cell was formed, but extensive necrosis formation was observed around the penetrating nematodes. In the other two resistant pepper lines (02G132 and 03G53), both giant cells and prominent necroses were formed, and the necrotic responses appeared to inhibit the further development of giant cells or accelerate their early degeneration. Although the nematode penetration was retarded significantly in the resistant cultivar/lines, all of the above results suggest that the disease resistance of pepper may be related to post-infectional defense mechanisms (nematode growth and development) more than pre-infectional ones (penetration and establishment). Variations in structural modifications in the resistant cultivar/lines may reflect their genetic differences related to the nematode resistance.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.386-392
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• 1998

Reproduction of the soybean cyst nematode (SCN), Heterodera glycines Ichinohe on the susceptible soybean cultivar, Lee 74, was significantly reduced by pre-, post- and simultaneous treatments of acetylsalicylic acid (ASA, aspirin). The control efficiencies were 60%, 64% and 87% for pre-, post- and simultaneous treatments, respectively. ASA had no significant effect on the survival of 2nd stage juveniles and their penetration into the soybean root tissues, but significantly inhibited the early stage nematode growth in the roots. Syncytia were formed 2∼3 days after inoculation in the susceptible soybean without ASA treatment, characterized by dense cytoplasm and increased cellular organelles such as mitochondria and endoplasmic reticulum. The nematode stylet was penetrated into the syncytial cell, and feeding tube was formed at the nematode stylet was penetrated into the syncytial cell, and feeding tube was formed at the nematode stylet entry. However, in the ASA treatments, syncytium was not formed or degenerated, depending on the root tissues. In the pre-treatments of ASA, nematode stylets did not penetrate into cells, showing callose-like cell wall thickening formed at the nematode probing sites, or retracted from the infected cells. The stylet penetration sites of syncytial cells appeared to be sealed off with fibrillar materials. With post-treatment of ASA, syncytia formed by the nematode were degenerated, characterized by degradation of syncytial cytoplasm.

• The Plant Pathology Journal
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• v.33 no.1
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• pp.66-74
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• 2017

This study was conducted to examine infectivity (penetration and gall and egg-mass formations) of the root-knot nematodes, Meloidogyne incognita and M. hapla, on carrots grown in soil conditions of 5 different soil textures consisting of bed-soil (b) and sand (s) mixtures (b-s mixtures) at the ratios of 10:0, 7:3, 5:5, 3:7, and 0:10. For M. incognita, the nematode penetration rates in b-s of 0:10 (100% sand) were significantly higher than in the other b-s mixtures, more greatly at 2 and 5 days after inoculation than at 10 DAI, while no significant differences in the penetration rates were mostly shown for M. hapla at the above DAI. However, for both nematodes, gall and egg-mass formations were remarkably increased in the b-s mixture of 0:10, compared to the other b-s mixtures, which is coincided with the general aspects of severe nematode infestations in sandy soils. This suggests the increased gall and egg-mass formations of M. incognita should be derived from the increased penetration rates in the sandy soil conditions, which provide a sufficient aeration due to coarse soil nature for the nematodes, leading to their mobility increased for the enhanced root penetration. For M. hapla, it is suggested that the sandy soil conditions affect positively on the healthy plant growth with little accumulation of the inhibitory materials and sufficient aeration, enhancing the nematode growth and feeding activities. All of these aspects provide information reliable for the development screening techniques efficient for the evaluation of the nematode resistance in the breeding programs.

• Korean Journal of Microbiology
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• v.22 no.1
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• pp.19-28
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• 1984

The nematode-trapping process by Arthrobotrys conoides was investigated with the aid of scanning and transmission electron microscopy. 1. A. conoides captures nematode by means of three-dimensional network. 2. The wall of trap cell was thicker than that of vegetative hypha and the trap cell was more rich in cell organelles such as endoplasmic reticulum, mitochondria and electrondense granule. 3. The electron-dense granule, which could be found only in trap organs, gradually disappeared during its penetration into nematode cuticle. 4. The osmiophilic area was found at adhering site between the trap organ and nematode cuticle. 5. In some cases, any appressorium was not found at the site of penetration. 6. When the fungal-nematode culture was conserved for 2~3 weeks, numerous young nematodes were found to be adhered to spores, resulting in death.

• Korean journal of applied entomology
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• v.27 no.1
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• pp.35-40
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• 1988

The control efficiency of the nematicides, aldicarb and carbofuran, in the population dynamics of the soybean cyst nematode(Heterodera glycines)was evaluated. Nematode viability, penetration and reproduction were examined in greenhouse experiments. Nematode viability(movement) was greatly reduced by aldicard, but mot by carbofuran. Penetration was inhibited by both chemicals. Percentages of Pentration relative to the untreated check 3 days after treatment were 0.4% and 1.7% for aldicarb and carbofuran, respectively. Systemic effect ot the nematicides were observed with both nematicides but effect was greater with aldicarb than with carbofuran. The total effect of the nematicides, applied ay the time of planting soybean in infested soil, appeared to be less than the sum of the contact and systemic effects on the initial population dynamics of H. glycines.

• Journal of Ginseng Research
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• v.20 no.3
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• pp.331-338
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• 1996

This study was conducted to screen the antagonistic plants on northern root-knot nematode (Meloidogyne) and to utilize those in its control. Egg hatching of M. hapla was found to be inhibited by 17 plant methanol extracts, and 11 plant extracts among them were also toxic to M. hapla second stage juvenile. Egg hatching of iW. hapla was also found to be inhibited by squeezed extracts of Cassia tora and Zea mays, and they were also toxic to M. hapla second stage juvenile. Extracts of Achyranthes japonica, Melia axedrach and Acorus graminens were toxic to M. hapla second stage with a juvenile mortality above 70clc at the 10 folds diluted concent ration and A. graminens was toxic to tested juvenile mortality above 50% at the 100 folds diluted concentration. The toxicity was directly propotional to the diluted concentration of the plant extracts and to the exposure period. Punica granatum, Acorns graminens and Melia axedrach were effective in inhibiting root penetration of JW. hapla juveniles, among of them p. granatum is most effective Percent inhibition of penetration by second and third stage juveniles into tomato slants penetrating by it was 72.7 and 82.4%, respectively.

• Korean journal of applied entomology
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• v.34 no.2
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• pp.112-119
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• 1995

Anatomical and biochemical changes of the corn root injured by the root lesion nematode, Pratylenchus vulnus, were examined to understand the interactions between the nematode and the crop which can be applied to a breeding program for nematode-resistant crop. The nematode and the crop which can be applied to be a breeding program for nematode-resistant crop. The nematode entered the cortex of corn root through its epidemis. They moved to other cortical cells by breaking their cell walls. They, finally, gathered around the endodermis of the roots and the bases of the root hairs. Parasitism of the nematode formed cavities within the root tissues where the females laid eggs. Major root damage by the nematode occurred in the cortical cells where must cell walls were broken and crushed to form empty spaces. These empty spaces in the base of the root resulted in this breakdown. Damage-induced biochemical changes of the corn roots were analysed by their total protein patterns and esterase activities in both control and nematode-infected roots. Denaturing gel did not show any significant difference in the banding patterns between them. Esterase patterns and activities, also, were not significantly different between the infected and the control roots.

• Korean journal of applied entomology
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• v.46 no.2
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• pp.313-318
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• 2007

Entomopathogenic nematode, Steinernema carpocapsae GSN1 strain was evaluated for the environmentally sound control of Tebenna issikii (Lepidoptera: Choreutidae) in the laboratory. The corrected mortality of Tebenna issikii larvae was 100% at the 40 infective juveniles (Ijs)/larva 3 days after treatment with S. carpocapsae GSN1 strain in Petri dish. $LC_{50}$ value of S. carpocapsae GSN1 strain against Tebenna issikii was 5.7 Ijs. The mean penetration numbers of Ijs of S. carpocapsae GSN1 strain at the 5, 10, 20, 40 and 80 Ijs/larva in a Tebenna issikii larva were 1.4, 1.4, 3.2, 5.6 and 11.9 Ijs/larva, respectively. However penetration rate of Ijs of S. carpocapsae GSN1 strain at 5 Ijs/larva was the highest among other nematode concentrations. Progeny of S. carpocapsae GSN1 strain in a Tebenna issikii larva was higher with increasing nematode concentration.

• Korean Journal Plant Pathology
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• v.2 no.3
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• pp.199-206
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• 1986

Penetration level, female development and histological changes in infected root tissues were investigated following inoculation with different inoculum levels (110,440 and 1760 juveniles/plant) of Heterodera glycines (SCN) race 3 on susceptible 'Lee' and resistant 'Pickett' soybean cultivars. Penetration level was lower in Pickett at the higher inoculum levels but no differences were detected in Lee. However, the lower penetration level in the resistant soybean cultivar appeared not to be directly related to plant resistance (female maturation). The number of females recovered from Lee was lower at the highest inoculum level. The number of females maturing on Pickett was much less than that on Lee, showing that changes of SCN population is associated with the number of SCN maturing rather than nematode penetration. In Lee mono-infection sites (a single nematode per site) syncytia had dense cytoplasm and no central vacuoles. while multi-infected sites (many overlapping nematodes per site) had syncytia with a large central vacuole and many small vacuoles. Resistant responses in mono-and multi-infected root tissues of Pickett were delayed and rapid necrosis, respectively. The differences in tissue response are suggested as a mechanism that controls density-dependent population changes in resistant and/or susceptible soybean cultivars.

• Parasites, Hosts and Diseases
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• v.39 no.1
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• pp.77-80
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• 2001

Cutaneous larva migrans (CLM) is a rare serpiginous cutaneous eruption caused by accidental penetration and migration in the skin with infective larvae of nematode that normally do not have the human as their host. Although CLM has a worldwide distribution, the infection is most frequent in warmer climates. More recently, they have been increasingly imported from the tropics or subtropics by travelers. We experienced two patients who had prutitic serpiginous linear eruption in their skin for a few weeks after traveling to the endemic areas (Brazil and Thailand, respectively) . After the treatment with albendazole, the skin lesions resolved with post-inflammatory hyperpigmentation. We report herein two cases of cutaneous larva migrans successfully treated with albendazole.