• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.359-359
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• 2017

A new soybean cyst nematode, H. sojae was reported from Korea in 2016. This species is closely related to H. glycines which has the same host plant. Morphological observations of the cyst, female, male and second-stage juveniles indicated that this species is differed from H. glycines. Especially, cysts of H. sojae appeared more round, shining and darker than that of H. glycines. The distribution of this new cyst nematode in soybean field in Korea is unknown so far. In 2016, 270 soil samples were collected from soybean fields and examined the existence of H. glycines and H. sojae. Total of 111 samples contained cysts (41.1%). Among them 77% were H. glycines and 23% were H. sojae. H. sojae is future threatening in soybean production area.

• 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.59 no.4
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• pp.361-369
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• 2020

This study aimed to investigate the differences in the effects of nematicidal materials (Burkholderia rinojensis, fluazaindolizine, fluopyram, fosthiazate, hydrogen peroxide, and imicyafos) on eggs and larvae of the sugar beet cyst nematode, Heterodera schachtii and clover cyst nematode, H. trifolii, which have recently become problematic in highland Chinese cabbage cultivation areas in Korea. Comparison of the hatching rates according to the test materials showed differences between treatments. In the treatment with fluopyram, fosthiazate, and imicyafos, a very high hatching inhibitory effect of 99% was observed in both nematodes, and there was no difference in the efficacy of treatments between nematode species except for that with hydrogen peroxide. Regarding the nematocidal activity of treatments against hatched larvae, only the fluazaindolizine treatment, despite showing a high hatching inhibitory effect, showed a low nematicidal effect of less than 30% against both nematodes, whereas a mortality rate of more than 90% was observed in the other treatments. There was no difference between nematode species in the reactions of the 2nd instar juveniles to all nematicidal test materials after 24 and 48 h of treatment. Although there are limitations to the laboratory experiment, the reaction to the nematicidal materials of the two cyst nematodes that damage the same host was similar, and simultaneous control is suggested in the areas where the two nematodes occur together.

• Horticultural Science & Technology
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• v.34 no.1
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• pp.195-205
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• 2016

Sugar beet cyst nematode, Heterodera schachtii, causes serious economic losses worldwide in Brassicaceae crops. In 2011, this nematode was first found in highland vegetable cultivation areas in Korea, and thereafter spread to the surrounding healthy Chinese cabbage fields. However, little has been documented on the biological and ecological characteristics of the sugar beet nematode in highland vegetable cultivation areas. In this study the dispersal of the sugar beet cyst nematode was examined, focusing on spreading through soil and/or water infested with the nematode. When farmers with work boots trampled on Chinese cabbage fields for 10 minutes, the number of cysts recovered from the soil attached to the working differed depending on the research sites. Under irrigation conditions of 2, 4, and 8 liters of water per $m^2$, the amounts of soils attached on the bottom of the work boots and the number of healthy cysts in the soils increased significantly with the increase in soil moisture, although the total number of cysts, eggs, and juveniles did not increase significantly. After driving on the farm road adjacent to cabbage fields infested with the sugar beet cyst nematode, cysts were also recovered from the soil attached to the vehicle's tires, suggesting that the sugar beet cyst nematode can spread to new fields through soil carried by vehicles and by farmers. An excavator and a motor truck could deliver 41 kg and 224 g, respectively, of soil on the shovel shoes and the wheels to other locations during the Chinese cabbage harvest, suggesting that farming equipment and transportation vehicles may be vital means by which the cyst nematode spreads to non-infested fields in the highland area of Korea. Runoff water also contained cysts, whose amounts increased after water irrigation onto the ridges to simulate rainy conditions, with no significant difference in the number of cysts with increasing amounts of irrigation water. All of these results confirmed that the sugar beet cyst nematode spreads through soil attached to work boots, harvesting tools, and transportation vehicles, especially during the harvest time, and through runoff water on rainy days. These observations suggest that personal sanitization and cleaning of working tools and vehicles are one of the most important means to prevent the dispersal of the sugar beet cyst nematode in fields.

• The Plant Pathology Journal
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• v.28 no.4
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• pp.401-408
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• 2012

Initial subcellular responses in susceptible (PI 274420) and resistant (cv. Hartwig) soybeans infected with the soybean cyst nematode (SCN) were examined 2 and 4 days after inoculation (DAI). Subcellular features common to both soybeans at 2 DAI included hypertrophied initial syncytial cells (ISCs) and syncytium-component cells (SCs) with a dense cytoplasm containing proliferated rough and smooth endoplasmic reticulum (RER and SER), a hypertrophied nucleolus, and reduced vacuoles, suggesting that the nematode-infected cells were dedifferentiated. In the resistant soybean, a striking initial subcellular difference from the susceptible soybean was the dilation of the RER, indicating ER dysfunction and leading to cell death. This disturbed nematode feeding, as evidenced by disrupted feeding tubes. In PI 274420, the ISC cytoplasm was depleted, with the exception of ER membranes, at 4 DAI, while the SC cytoplasm was dense with proliferation of starch-containing plastids around multiple nuclei that might be derived from the congregation of nuclei in the neighboring SCs and in part by nuclear division without cytokinesis. In cv. Hartwig, syncytia were necrotized with secondary cell wall thickening outside the plasma membrane and an extremely dense cytoplasm containing a nucleus with an electron-lucent nucleolus, accompanied by the proliferation of closely stacked parallel RER and ribosomes. These results suggest that syncytia develop continuously in PI 274420 to produce and store nutritional substances in SCs, providing for the nematode through ISC until maturation, but in cv. Hartwig, syncytia degenerate early due to excessive metabolism, blocking nematode feeding and cytoplasmic connections with adjacent intact cells.

• Korean journal of applied entomology
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• v.26 no.4 s.73
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• pp.203-207
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• 1987

Studies were conducted to investigate the race distribution of soybean cyst nematode (Heterodera glycines Ichinohe) in Korea. The results are abstracted as follows. The soybean cyst nematode populations collected from Kangwon Province were identified as races 1 and 3; the nematode populations collected from Kyunggi Province were identified as race 3, 5 and c and those collected from Chungnam Province were identified as races 1 and 5. From the total 21 populations 11 populations or 52.4% of the total were race 1; 6 populations or 28.6% of the total were race 5; 3 populations or 14.3% of the total were race 3 and one population or 4.8% of the total were race c. Soybean cyst nematode populations from the same district, at least from the same 'myeon' district were identified as same race. Of these 4, race 3 has not been recorded in Korea yet.

• 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.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.389-403
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• 2016

Sugar beet nematode (Heterodera schachtii Schmidt) was first detected in 2011, in Chinese cabbage grown in the highland areas of Korea. Chemical control of the nematode by nematicides is not feasible due to its cyst-forming characteristics; therefore, the cultivation of non-host crops is a preferable alternative to utilize nematode-infected fields. In this study, a total of 276 plant cultivars belonging to 18 different families were screened to evaluate their resistance to the nematode. Based on the number of cysts formed following nematode inoculation, the tested crops were classified into 3 levels: susceptible, moderately susceptible, and resistant/immune. Among the 276 cultivars tested, 106 cultivars were susceptible, 40 cultivars were moderately susceptible, and 130 cultivars were resistant/immune. Among the resistant/immune cultivars, cyst formation was not observed on eggplant, tomato, lettuce, perilla, carrot, celery, watermelon, oriental melon, cucumber, pumpkin, chives, onion, welsh onion, balloon flower roots, deodeok (Codonopsis lanceolata), Jandae (Adenophora triphylla), and bean. Therefore, these plants are regarded as immune to the cyst nematode. However, many crops belonging to Solanaceae, Asteraceae, Chenopodiaceae, and Poaceae families showed moderate susceptibility or immunity, depending on the crop or cultivar. This study provides a basis for alternative crop recommendations for sugar beet nematode cyst-infected farms in Chinese cabbage production areas.

• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.177-180
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• 2008

Worldwide, cyst nematode(Heterodera glycines Ichinohe) is the most destructive pathogen of cultivated soybean. In the USA, current annual yield losses are estimated to be nearly a billion dollars. Crop losses are primarily reduced by the use of resistant cultivars. Nematode populations are variable and have adapted to reproduce on resistant cultivars over time because resistance primarily traces to two soybean accessions. It is important to use diverse resistance sources to develop new nematode resistant cultivars. Soybean PI 494182 is a recent introduction from Japan and found to be resistant to multiple nematode populations. It is yellow seeded and maturity group 0. We have determined inheritance of resistance in PI 494182 using $F_{2:3}$ families derived from cross PI 494182 X cv. Skylla. Skylla is a susceptible parent. Three nematode populations, races 1, 3, and 5, corresponding to HG types 2.5.7, 0, and 2.5.7 were used to bioassay 162 $F_{2:3}$ families in greenhouse experiments. Based on Chi-square tests, a two-gene model is proposed for resistance to race 1 and a three-gene model is proposed for conditioning resistance to both races 3 and 5. Correlation coefficient analysis indicated that some genes conditioning resistance to races 1, 3, and 5 are shared or closely linked with each other. These results will be useful to soybean breeders for developing soybean cultivars for broad resistance to nematodes.