• Korean journal of applied entomology
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• v.45 no.2 s.143
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• pp.211-216
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• 2006

Total of 36 sweet potato field soils were sampled to survey the occurrence of the root-knot nematodes (RKN). The 61% of sweet potato fields in Haenam, 40% in Iksan and 31% in Yeju were infested with RKN, respectively. Average population density of RKN was 324 juveniles per 300 g soil. The resistance screening of sweet potato cultivars against RKN was carried out by using clay pots in a greenhouse. Average temperature under ground 10 cm in pot was 21.5$^{\circ}C$ during the test. There was no difference in number of egg sacs among different inoculation methods, however the egg-inoculation method was easy for treatlnent and had stable far results. The multiplication ratio of Melioidogyne incognita differed from 6.3 times (Jeungmi) to 63.2 times (Yulmi) by sweet potato cultivas. There were no cultivars showing resistance to M. incognita, but Jinmi, Jeungmi and Borami had resistance to if arenaria, M. hapla and M. javanica.

• Research in Plant Disease
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• v.22 no.4
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• pp.249-256
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• 2016

To investigate the incidence of plant-parasitic nematodes from plastic-house fields of strawberry, 170 soil samples were collected from the main producing area of strawberry in Korea from 2014 to 2015. Based on the investigation, root-lesion nematode (RLN; Pratylenchus spp.) and root-knot nematode (RKN; Meloidogyne spp.) are the most important pests in plastic-house fields of strawberry with 57% and 36% incidences, respectively. Among the collected fields, 96 and 63 fields were infected RNL and RKN, respectively with 44 fields (38.8%) being detected at both nematode. High degree of incidence of both nematodes were observed in the regions of Jinju, Gyeonnam Province, Korea. For identification of species level, phylogenetic and distance analysis were performed using RLN and RKN isolates generated from the regions of Jinju. The results indicated that the RLN and RKN isolates were Pratylenchus vulnus and Meloidogyne hapla, respectively. This study showed that P. vulnus and M. hapla could be most dominant species in plastic-house fields of strawberry. This data will provide basic knowledge for development of effective control strategies.

• Korean journal of applied entomology
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• v.44 no.4 s.141
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• pp.317-323
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• 2005

This study was conducted to survey plant-parasitic nematodes and their damages on Codonopsis lanceolata Trautv at 116 fields of 15 major cultivation areas in Korea. Among the 9 plant-parasitic nematode genera detected in the fields, Ditylenchus citri, Meloidogyne hapla, M. incognita, Pratylenchus neglectus, Tylenchorynchus clayton were identified. M. hapla Chitwood showing the highest field infection rate of 61.9% followed by Tylenchus spp. 16.1%, Pratylenchus neglectus 7.8%, Ditylenchus citri 5.1%, and Helicotylenchus sp. 5.1%. Average field infection rate of root-knot nematodes in 2-year-old C. lanceolata was 67.0%, and the average plant infection rate was 60.2%. The average yield decrease rate was 10%. The damage rate by the root-hot nematode increased as the cultivation year extended in Jeonbuk province, and the damage was also higher in flat land than in mountainous areas.

• The Plant Pathology Journal
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• v.30 no.1
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• pp.75-81
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• 2014

In total, 170 carrot lines developed in Korea were screened for resistance to Meloidogyne incognita race 1 to select parental genetic resources useful for the development of nematode-resistant carrot cultivars. Using the gall index (GI), gall formation was examined on carrot roots inoculated with approximately 1,000 second-stage juveniles of the nematode 7 weeks after inoculation. Sixty-one carrot lines were resistant (GI ${\leq}1.0$), while the other 109 were susceptible (GI > 1.0) with coefficient of variance (CV) of GI for total carrot lines 0.68, indicating low-variation of GI within the lines examined. The histopathological responses of two carrot plants from resistant and susceptible lines were examined after nematode infection. In susceptible carrots, giant cells formed with no discernible necrosis around the infecting nematodes. In the resistant carrot line, however, no giant cells formed, although modified cells were observed with extensive formation of necrotic layers through their middle lamella and around the infecting nematodes. This suggested that these structural modifications were related to hypersensitive responses governed by the expression of true resistance genes. Therefore, the Korean carrot lines resistant to the nematode infection are potential genetic resources for the development of quality carrot cultivars resistant to M. incognita race 1.

• The Plant Pathology Journal
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• v.30 no.3
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• pp.288-298
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• 2014

We examined the efficacy of a bacterium for biocontrol of the root-knot nematode (RKN) Meloidogyne hapla in carrot (Daucus carota subsp. sativus) and tomato (Solanum lycopersicum). Among 542 bacterial isolates from various soils and plants, the highest nematode mortality was observed for treatments with isolate C1-7, which was identified as Bacillus cereus based on cultural and morphological characteristics, the Biolog program, and 16S rRNA sequencing analyses. The population density and the nematicidal activity of B. cereus C1-7 remained high until the end of culture in brain heart infusion broth, suggesting that it may have sustainable biocontrol potential. In pot experiments, the biocontrol efficacy of B. cereus C1-7 was high, showing complete inhibition of root gall or egg mass formation by RKN in carrot and tomato plants, and subsequently reducing RKN damage and suppressing nematode population growth, respectively. Light microscopy of RKN-infected carrot root tissues treated with C1-7 showed reduced formation of gall cells and fully developed giant cells, while extensive gall cells and fully mature giant cells with prominent cell wall ingrowths formed in the untreated control plants infected with RKNs. These histopathological characteristics may be the result of residual or systemic biocontrol activity of the bacterium, which may coincide with the biocontrol efficacies of nematodes in pots. These results suggest that B. cereus C1-7 can be used as a biocontrol agent for M. hapla.

• Korean journal of applied entomology
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• v.39 no.2
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• pp.111-115
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• 2000

Fifty-two nematode predatory fungi were isolated from 37 soil samples collected from eight provinces in Korea. Isolated fungi were tested their predacity against Rhabditis sp. and Meloidogyne incognita in petri dish, and against M. incognita in greenhouse pot experiments. Fifty isolates had trapping organ of adhesive networks and two isolates had adhesive column or adhesive knob. In petri dish experiments, 5 1 isolates against Rhubditis sp. and 26 isolates against M. incognita showed over 91 % of predacity; in greenhouse experiments, however, only three isolates showed over 81% of predacity. These results imply that the results from the laboratory experiments are not consistent with those from the greenhouse experiments. Therefore, to select a promising biocontrol predatory fungi for plant-parasitic nematodes, the screening experiment should be conducted in conditions close to nature.

• Journal of Applied Biological Chemistry
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• v.55 no.4
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• pp.247-252
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• 2012

This study examined the control effects of amino acid biochemical agent extracted from chicken feathers on Meloidogyne incognita for the purpose of developing an environmentally friendly nematicidal agent that can replace chemical control of root-knot nematodes (RKN). We investigated the lethal effects of J2 juveniles for 19 types of commercial amino acids. As a result, five kinds of amino acids (L-asparagine, L-aspartic acid, L-methionine, L-tyrosine, L-cysteine) showed mortality rate of more than 50% at a concentration of 50 mM. L-asparagine showed the highest mortality rate at 94%. We also investigated the lethal effect of J2 juveniles and suppressive effects of egg hatching by feather amino acids (FAA) biochemical agent. It showed that the mortality rate of J2 juveniles was more than 80% and suppression rate of egg hatching was 74% at 1/50 concentrations of FAA. As a result of conducting a tomato pot culture experiment for 60 days after treating 1/50 concentrations of FAA biochemical agent in rhizosphere soil, it showed that the control effects were 63% of juveniles density in the soil, 59% of egg mass and 61% of root gall index, respectively. Based on the above results, it is considered that the FAA biochemical agent extracted from chicken feathers can be used as an environmentally friendly nematicidal agent of RKN.

• Journal of Life Science
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• v.17 no.12
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• pp.1605-1609
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• 2007

The created microbial pesticide was used to examine its effects using the inside-pot test method. The selected microbial pesticide KBC3017 particle pesticide manufactured by using Monacrosporium thaumasium was used in the farm-house outdoor test to find the optimum consistency and its effects. The more amount used, the better effect it showed. However, the optimum consistency was 2% and the KBC3017 particle pesticide for which the diatomite and raw jade powder were used as an increaser, when used 2% level of the total amount of soil, showed 71% effect on nematode prevention. The root and the stem of crops were better compared to those without any pesticide used.

• 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.

• Research in Plant Disease
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• v.23 no.3
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• pp.241-248
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• 2017

The purpose of this study was to develop rapid methods for distinguishing between Heterodera schachtii and H. glycines detected from chinese cabbage fields of highland in Gangwon, Korea. To do this, we performed PCR-RFLP and PCR with the primers set developed in this study for GC147, GC408 and PM001 population, H. schachtii, and YS224, DA142 and BC115 population, H. glycines. Eight restriction enzymes generated RFLP profiles of mtDNA COI region for populations of H. schachtii and H. glycines, repectively. As a result, treatment of two restriction enzymes, RsaI and HinfI, were allowed to distinguish H. schachtii from H. glycines based on the differences of DNA band patterns. The primer set, #JBS1, #JBG1 and #JB3R, amplified specific fragments with 277 and 339 bp of H. schachtii, 339 bp of H. glycines, respectively, while it did not amplify fragments from three root-knot nematodes and two root-lesion nematodes. Thus, the primer set developed in this study could be a good method, which is used to distinguish between H. schachtii and H. glycines.