• The Plant Pathology Journal
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• 제39권6호
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• pp.575-583
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• 2023

Fusarium root rot is an increasingly severe problem in soybean cultivation. Although several Fusarium species have been reported to infect soybean roots in Heilongjiang province, their frequency and aggressiveness have not been systematically quantified in the region. This study aimed to investigate the diversity and distribution of Fusarium species that cause soybean root rot in Heilongjiang province over two years. A total of 485 isolates belonging to nine Fusarium species were identified, with F. oxysporum and F. solani being the most prevalent. Pot experiments were conducted to examine the relative aggressiveness of different Fusarium species on soybean roots, revealing that F. oxysporum and F. solani were the most aggressive pathogens, causing the most severe root rot symptoms. The study also assessed the susceptibility of different soybean cultivars to Fusarium root rot caused by F. oxysporum and F. solani. The results indicated that the soybean cultivar DN51 exhibited the most resistance to both pathogens, indicating that it may possess genetic traits that make it less susceptible to Fusarium root rot. These findings provide valuable insights into the diversity and distribution of Fusarium species that cause soybean root rot and could facilitate the development of effective management strategies for this disease.

• 한국균학회지
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• 제8권1호
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• pp.53-57
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• 1980

An undescribed black root rot of soybean, caused by Cylindrocladium crotalariae, was observed in Suweon area. The diseased plants showed yellowing at the top and dry rot at the root. Lesions of roots and stems in the soil were red to brown and main roots were cracked. Although not observed the disease in the field, leaves of inoculated test plants in the greenhouse exhibited circular, brown lesion surrounded by chloratic halos. The fungus was recovered in culture from the infected stem and root, and the perithecia of Calonectria crotalariae were demonstrated to be present as well as the cylindrocladium state. The fungus was pathogenic to the root, stem, petioles and leaves of soybean. The probable source of primary inoculum was microsclerotia formed in infected soybean root and stem from the previous season's soybean debris. Black root rot by this fungus was considered to be one of detrimental factors to the maximum yield of soybean. From the morphological and physiological characteristics and pathogenic behaviors, this fungus was identified as Cylindrocladium(Calonectria) crotalariae.

• 한국균학회지
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• 제11권2호
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• pp.99-101
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• 1983

Black root rot caused by Cylindrocladium crotalariae is one of the most serious soilborne disease in soybean. Plant height reduction of Hwangkeum Kong was 38% by the rotting of the whole main root and 9% by rotting of the half of the main root as compared with partial discoloration in the main root. Pod number per plant and seed weight were significantly reduced by the increase of the disease severity. Important yield components such as number of pods per plant and seed weight were negatively correlated with the soybean black root rot severity.

• The Plant Pathology Journal
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• 제35권3호
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• pp.219-233
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• 2019

Soybean cultivars susceptible to Phytophthora root and stem rot are vulnerable to seed rot and damping-off of seedlings and young plants following an infection by Phytophthora sojae. In this study, the disease responses of Japanese soybean cultivars including currently grown main cultivars during the early growth stages were investigated following infections by multiple P. sojae isolates from Japanese fields. The extent of the resistance to 17 P. sojae isolates after inoculations at 14, 21, and 28 days after seeding varied significantly among 18 Japanese and two US soybean cultivars. Moreover, the disease responses of each cultivar differed significantly depending on the P. sojae isolate and the plant age at inoculation. Additionally, the treatment of 'Nattosyo-ryu' seeds with three fungicidal agrochemicals provided significant protection from P. sojae when plants were inoculated at 14-28 days after seeding. These results indicate that none of the Japanese soybean cultivars are completely resistant to all tested P. sojae isolates during the first month after sowing. However, the severity of the disease was limited when plants were inoculated during the later growth stages. Furthermore, the protective effects of the tested agrochemicals were maintained for at least 28 days after the seed treatment. Japanese soybean cultivars susceptible to Phytophthora root and stem rot that are grown under environmental conditions favorable for P. sojae infections require the implementation of certain practices, such as seed treatments with appropriate agrochemicals, to ensure they are protected from P. sojae during the early part of the soybean growing season.

• 한국약용작물학회지
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• 제23권3호
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• pp.223-230
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• 2015

To study the effect of crop rotation on the control of ginseng root rot, growth characteristics and root rot ratio of 2-year-old ginseng was investigated after the crops of 18 species were cultured for one year in soil contaminated by the pathogen of root rot. Fusarium solani and Cylindrocarpon destructans were detected by 53.2% and 37.7%, respectively, from infected root of 4-year-old ginseng cultivated in soil occurring the injury by continuous cropping. Content of $NO_3$, Na, and $P_2O_5$ were distinctly changed, while content of pH, Ca, and Mg were slightly changed when whole plant of crops cultured for one year were buried in the ground. All of EC, $NO_3$, $P_2O_5$, and K were distinctly increased in soil cultured sudangrass, peanut, soybean, sunnhemp, and pepper. All of EC, $NO_3$, $P_2O_5$, and K among inorganic component showed negative effect on the growth of ginseng when they were excessively applied on soil. The growth of ginseng was promoted in soil cultivated perilla, sweet potato, sudangrass, and welsh onion, while suppressed in Hwanggi (Astragalus mongholicus), Deodeok (Codonopsis lanceolata) Doraji (Platycodon grandiflorum), Gamcho (Glycyrrhiza uralensis), Soybean. All of chicory, lettuce, radish, sunnhemp, and welsh onion had effective on the inhibition of ginseng root rot, while legume such as soybean, Hwanggi, Gamcho, peanut promoted the incidence of root rot. Though there were no significant correlation, $NO_3$ showed positive correlation, and Na showed negative correlation with the incidence of root rot.

• 농약과학회지
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• 제11권1호
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• pp.18-26
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• 2007

콩 검음뿌리썩음병의 방제를 위한 살균제 선발을 위하여 실내 및 온실 검정을 실시하였다. 한천희석법과 96-well microtiter plate법을 이용하여 총 25종의 살균제의 병원균에 대한 생육 억제 효과를 검정하였다. 보호용 살균제 중에서 iminoctadine을 제외한 dithianon, dichlofluanid, mancozeb, captan 등은 한천희석법에서 조사한 병원균의 생육을 억제하는 $EC_{50}$값은 $500{\mu}g\;mL^{-1}$ 이상으로 효과가 매우 낮았지만, 96-well microtiter plate법에서는 4.65, 0.61, 4.64, $0.29{\mu}g\;mL^{-1}$로, 병원균의 포자 발아에 대하여 매우 높은 활성을 보였다. 그러나 ergosterol 생합성을 저해하는 살균제 (EBI) 그룹은 물질에 따라 매우 다른 살균활성을 보였다. Difenconazole의 경우에는 균사생육보다는 포자발아 억제활성이 높았고, prochloraz의 경우에는 균사 생육활성과 포자 발아억제활성이 서로 유사하였다. 이에 비하여 다른 EBI 살균제들은 포자발아보다는 균사생육저해활성이 큰 것으로 나타났다. Carbendazim과 diethofencarb의 혼합제와 dazomet만이 두 가지의 실내 검정법 모두에서 우수한 효과를 보였다. Carbendazim과 diethofencarb의 혼합제를 비롯한 8종의 살균제를 선발하여 온실검정을 실시한 결과, carbendazim과 diethofencarb의 혼합제만이 병원균을 접종하기 2일 전과 후에 토양에 처리하였을 때, 75와 76.7%의 효과를 보였고, tebuconazole은 병원균을 접종하고 2일 후에 관주처리 하였을 때, 83.3%의 효과를 보였다.

• The Plant Pathology Journal
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• 제19권6호
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• pp.280-283
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• 2003

A soybean-sprout rot epidemic occurred in a mass production soybean sprout factory in 2000 and 2001 in Korea, which caused up to 20% production loss. Among the causal pathogenic bacteria and fungi, Pythium deliense was found to be the dominant pathogen of severe root and hypocotyls rot, particularly in recirculating water system. An average of 90% of the isolated fungi from the rotted sprout on potato dextrose agar were Pythium sp. The fungal density of Pythium in the sampled water was monitored in the recycled water system for 1 year using a selective medium (com meal agar with Pimaricin, 10 mg； Rifampicin, 10 mg； and Ampicillin, 100 mg per 1 liter). The drained water from the soybean-sprout cultivation always had a certain amount of fungus in it. The removal of Pythium from the recycling water system must be thorough, safe, and environment friendly. However, the pathogen in the water was easily found even after ozone and chlorine treatments, which were devised on the recycling system for the removal of microorganisms. 5-$\mu\textrm{m}$ pore size filter was applied and was able to successfully control the disease. As the sprout industry increasingly shifts into mass production, the demand for water will increase continuously. Recycling water for sprout production is eco-friendly. However, a process must be devised to be able to first decompose organic matters before Pythium zoospores are filtered.

• 한국응용곤충학회지
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• 제19권4호
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• pp.228-233
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• 1980

The infection rate of soybean black root rot disease caused by Calonectria crotalariae was about $14\%$. The isolated fungi from the infected soybean roots and stems were Calonectria crotalariae, Fusarium solani, F. roseum, Phomopsis sojae, Pythium aphanidermatum, Rhizoctonia solani and Macrophomina sp. Among them, C. crotalariae was the most virulent pathogen under the laboratory conditions. Mycelial growth and microsclerotial formation were good on PSA containing 1000cc of water, 100g of potato and 20g of sugar. Mycelial growth, sporulation and microsclerotial formation were good on sterilized root. Perithecial formation was better in the dark condition than in the light. Survival of macroconidia was not available between $0\~25\%$ soil water content. Microsclerotia and mycelium in infected plant debris were survived for 4 months at to $8\%\;50\%$ soil water content. The plant height, when inoculated with $1.2\%$ inoculum density, reached approximately half of uninoculated plants. Disease severity was much higher at nonsterilized soil than completely sterilized soil. It was determined that the host range of this pathogen includes soybean, peanut, green bean and red bean.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 춘계학술대회
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• pp.51-51
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• 2022

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.92.2-93
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• 2003

Severe soybean-sprout rot was found at the mass productive factory in 2000 and 2001 and it caused 10-20％ loss of the production. Pythium sp. was isolated almost 90％ by potato dextrose agar from rotted root and hypocotylsof the sprouts. And the pathogencity tests using test tubes with 2％ water agar and small containers (30 ${\times}$ 30 ${\times}$ 50 cm, WxLxH) cultivation were shown a similar rot on roots and hypocotyls. The fungal mycelium grew rapidly on the water agar and it prevented the seed germination. Density of the Pythium sp. in the recycled water system at the factory was periodically measured using a selective medium, corn meal agar with Pimaricin 10 mg, Rifampicin 10 mg, Ampicillin 100 mg per 1 liter in order to check the contamination of recycled water. After fitering step using 5 and 1 ml in the recycled system was applied and it was effectively controlled Pythium rot. The daily yield of sprout was stable and the occurrenceof Pythium in the recycled water was much less after filtering. The fungal isolates were identified as Pythium deliense Meurs based on various mycological characteristics on corn meal agar and sucrose-asparagine bentgrass leaf culture medium. P. deliens oogonia were spherical, smooth, 19-23 urn in diameter, and their stalk bending toward antheridia. Antheridia were straw hat-shaped, curred club-shaped, therminal or intercalary, monoclinous, occasionally diclinous, 12∼15 ${\times}$ 8∼11 um, 1(∼2) per oogonium.