• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.657-665
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• 2023

The root-lesion nematode Pratylenchus spp. is the most important plantparasitic nematode due to its worldwide distribution, wide host ranges, and migratory endoparasitic characteristics. One population of Pratylenchus collected from the giant pussy willow (Salix chaenomeloides Kimura) in the Andong area as part of a nematode survey in Korea was characterized morphologically and by molecular methods. The analysis of morphological measurements and morphometric characteristics, as well as DNA sequencing of the rRNA large subunit (LSU) D2/D3 expansion segments and the internal transcribed spacer (ITS) gene sequence, confirmed the identity of this population as P. hippeastri. This study is the first report of P. hippeastri associated with Salix chaenomeloides in Korea and worldwide. Further studies on distribution and pathogenicity in different P. hippeastri host crops, such as grapevines, strawberries, and apples, are necessary. The taxonomic keys to 16 Pratylenchus species in Korea are provided.

• 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.

• The Plant Pathology Journal
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• v.34 no.4
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• pp.297-307
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• 2018

The sugar beet cyst nematode, Heterodera schachtii is a well known pathogen on Chinese cabbage in the highland fields of Korea. However, a race of cyst forming nematode with close morphological resemblance to H. trifolii was recently isolated from the same Chinese cabbage fields. Morphological species differentiation between the two cyst nematodes is challenging, with only minor differences between them. Thus, this study described the newly intercepted H. trifolii population, and reviewed morphological and molecular characteristics conceivably essential in differentiating the two nematode species. A comparison of morphometric measurements of both infective juveniles and vulval cones of cysts showed significant differences between the two cyst nematodes. When total RNA and genomic DNA were extracted from a mixed field population, COI genes and ITS regions were clearly amplified with primers of the two Heterodera species, suggesting that Heterodera population collected from the Chinese cabbage field consisted of a mixture of two species. COI and ITS of H. trifolii were predominantly amplified from nucleotides prepared from H. trifolii monoxenic population whereas those of H. schachtii were strongly detected in H. schachtii monoxenic cultures. Thus, this study confirms the coexistence of the two species in some Chinese cabbage fields; and the presence of H. trifolii in Korea is reported here for the first time.

• The Plant Pathology Journal
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• v.25 no.2
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• pp.189-192
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• 2009

The effect of plant extracts of eucalyptus (Eucalyptus chamadulonsis), garlic (Allium sativium), marigold (Tagetes erecta) and neem (Azadirachta indica) and essential oils were tested on the suppression of root-knot nematode Meloidogyne incognita under greenhouse and field conditions. In vitro study, all tested treatments had nematicidal effect on nematode juveniles after 24 and 48 hours from exposures. The highest percentage of nematode mortality was achieved by application of neem extract (65.4%), essential oils (64.4%) and marigold extract (60.5%), followed by garlic and eucalyptus extracts (38.7-39.5%). Under greenhouse and field conditions, neem extract and essential oils treatments were more effective in reducing population numbers of the M. incognita in soil and root gall index compared to other treatments. In field experiments, the maximum protection of tomato plant against root-knot nematode was obtained by application of neem and essential oil treatments, 44.2 and 32.6%, respectively.

• Korean Journal Plant Pathology
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• v.10 no.4
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• pp.319-324
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• 1994

The monoxenic culture of the fungivorous nematode, Aphelenchus avenae, was applied for the control of soil-borne ginseng pathogens such as Fusarium solani and Rhizoctonia solani. Fungivorous nematode populations were measured in a field to examine relationships between the nematode populations and suppression of ginseng root diseases. Inoculation of A. avenae (5000 nematodes per petri-dish) reduced the colonization of the Fusarium mycelium on root discs of ginseng and carrot by 80.0% and 60.5%, respectively. A. avenae also significantly reduced the occurrence of damping-off of ginseng by R. solani pathogenic to ginseng, and no plant damage by the nematode was noted. In a 3-year-old ginseng field infested with Cylindrocarpon destructans, plant missing caused by root rot positively correlated to the density of potato rot nematode, Ditylenchus destructor, but it was reduced with the population of A. avenae, suggesting that A. avenae might inhibit the occurrence of ginseng root rot.

• Journal of Forest and Environmental Science
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• v.33 no.2
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• pp.105-112
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• 2017

The distribution and form of pine wood nematode (PWN) were investigated in Jinju-si and Sacheon-si areas, where infested with pine wilt disease (PWD). The average PWN population per g of the tubulation part in the wilted Japanese balck pine were 381.2 and 341 in Jinju-si and Sacheon-si, respectively. The PWN population per g of affected Japanese black pine with wilt rate below 60% were 556 and 518 in Jinju-si and Sacheon-si, respectively. The ratios of PWN and other plant-parasitic nematode in the wilted Japanse black pines were 48% vs. 52% in Jinju-si and 53% vs. 47% in Sacheon-si after exposure to PWD for 1 year. The survivorship of pine wood nematode in the sampled trees after 1 year was 0-10% in the Jinju-si area and 5-20% detected in the Sacheon-si area. In the forest areas affected by PWN, the highest survival rates were 37.2% and 39.8% at 25 cm diameter at breast height (DBH) in Jinju-si and Sacehon-si, respectively, while the highest wilt rates were 30.5% and 28.3% at 30 cm DBH in Jinju-si and Sacehon-si, respectively.

• Animal cells and systems
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• v.14 no.1
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• pp.31-36
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• 2010

The pinewood nematode Bursaphelenchus xylophilus causes pine wilt disease and is a serious economic concern for the forest industry of South Korea. To achieve effective control with limited resources, it is necessary to clarify the transmission routes and mechanisms of dispersal of this organism. Highly polymorphic and easy-to-use molecular markers can be used for investigating this aspect. In this study, we evaluated the usefulness of amplified fragment length polymorphisms (AFLPs) for investigating the genetic variations of B. xylophilus and related individuals from China, Japan, and South Korea. The AFLP patterns obtained in our study were similar to the microsatellite patterns reported in a previous study; our AFLP patterns indicated high genetic variability and cryptic genetic structure, but did not indicate any peculiar geographic structure. Moreover, the genetic distances between individuals suggested that the Korean population was affected to a greater extent by the Chinese population than the Japanese population. Further, the gene flow among the related species appeared to be limited; however, there may be also the possibility of genetic introgression among species. These results confirm the usefulness of AFLPs for understanding the epidemiology of pine wilt disease, thereby contributing to the effective control of this disease.

• Journal of Applied Biological Chemistry
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• v.48 no.4
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• pp.161-166
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• 2005

Among 24 isolates of fluorescent Pseudomonads, 5 isolates named as LPT1, LPT2, LPT3, LPT4 and LPT5 were screened in vitro for their nematicidal activity against cyst forming nematode, Heterodera cajani causing patchiness, poor and stunting growth besides discoloration in Sesamum indicum. Second stage juveniles of H. cajani hatched from egg masses were collected from roots of host plant and subjected to fresh and heat-treated culture filtrate of isolates for 24 h. Mortality of H. cajani was recorded on the basis of parameters used for test organism bioassay. Among these isolates, Pseudomonas aeruginosa LPT5 caused maximum mortality towards second stage juvenile of H. cajani in vitro. Five isolates were used as seed coating for the management of cyst forming nematode H. cajani on sesame in green house condition. The strains LPT5 was better than the other strains in reducing the population of H. cajani both in vitro and in vivo. The reduction in cyst and juveniles population was found to be 49 and 60%, respectively when seeds were coated with strain LPT5. Among other strains, LPT4 was also found to inhibit the cyst and juveniles population 12 and 36% respectively. Increases in early vegetative plant growth parameters recorded in both in vitro and in vivo further revealed the significance of indigenous bacteria in comparison to introduced strain.

• Korean journal of applied entomology
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• v.19 no.3 s.44
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• pp.153-155
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• 1980

In pot experiment, relations between bulb nemationde, Ditylenchus dipsaci, and growth and yield of garlic were followed. There was no effect of height growth on bulb nematode, but growth of volume was reduced at more than 250 nematodes per pot. Yield loss of garlic was more than $20\%$ when nematode density was about 30 per bulb in late-April. Tolerance limit should be about 20 nematodes per bulb at early growing stage. Reproduction of bulb nematode was good when initial population had been low.

• Korean journal of applied entomology
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• v.12 no.4 s.17
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• pp.143-146
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• 1973

A greenhouse experiment was conducted to find out the influence of the inoculation density of Aphelenchoides besseyi on the growth of rice plant and the body length of female nematode. The rice plants showed reduced height, number of tillers and dry weight of plant when the nematode was inoculated. The body length of female nematode significantly decreased as the initial population density increased.