• The Korean Journal of Pesticide Science
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• v.7 no.3
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• pp.216-222
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• 2003

In order to develop effective control methods for Bakanae disease caused by Gibberella fujikuroi (Saito) Ito during rearing of rice seedlings, we investigated the disease resistance of 15 rice varieties to G. fujikuroi and control effect of six seed disinfectants, and tried to improve the using methods of the seed disinfectants. Disease resistance was tested by investigating the disease incidence on each rice cultivar grown in rice seedling box infested with or not infested with G. fujikuroi at 30 days after sowing seeds and 20 days after heading date. The results showed that Hwayongbyeo, Dongjinbyeo, Hwoanbyeo, Nonghobyeo, Nampyeongbyeo, and Hwojinbyeo were resistant G. fujikuroi, meanwhile Keulubyeo, Sobibyeo, Odaebyeo, Junambyeo, Samchonebyeo, Sangjubyeo, and Hwabongbyeo were susceptible. Three seed disinfectants, prochloraz, fludioxonil, and carproamid + thiram + fludioxonil controlled Bakanae disease of rice very well, while bonomyl + thiram, thiophanate-methyl + thiram and thiophanate-methyl + triflumizole did not suppress the disease enough. Water temperature was turned to be an important factor for controlling the disease by treating seed disinfectants. Prochloraz showed 61% control value on the disease at $10^{\circ}C$, but it showed above 95% control value at the range of $30-35^{\circ}C$. It was confirmed that the control effect of seed disinfectants increased with increasing water temperature. Meanwhile soaking period of rice seeds in the suspension of seed disinfectants and chemical dosage had no high relation to control the disease. This results suggest that rice varieties, water temperature, and optimal selection of suitable seed disinfectants are very important to control Bakanae disease effectively.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.49-49
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• 2015

Over the past decade, clubroot has emerged as a major constraint to canola (Brassica napus) production in central Alberta, Canada. The number of fields with confirmed P. brassicae infestations in Alberta has increased steadily from 12 in 2003 to nearly 2,000 in 2014. Management of clubroot on canola has focused on sanitization of field equipment, soil amendments to reduce viable pathogen populations, long rotations out of susceptible crops and cropping of resistant cultivars. Clubroot resistance is the most effective and economical method of disease mitigation, but the recent identification of isolated P. brassicae populations with novel virulence phenotypes capable of overcoming resistance in most canola cultivars highlights the variable nature and adaptability of the pathogen. Recent studies have shown slight reductions in pathogen populations through crop rotations, but much more substantial reductions in spore populations in heavily infested areas near field entrances using fumigants such as Vapam (metam-sodium) or Basamid (dazomet). Greenhouse trials showed that seedling emergence, plant height and root weight increased, while primary and secondary infection and disease severity decreased with increased Basamid dosage. However, field trials showed some phytotoxicity. Application of Vapam at rates of 0.4 to $1.6mL\;L^{-1}$ soil resulted in 12-16 fold reductions in clubroot severity and primary and secondary infection. Vapam also was effective in reducing clubroot severity and improving canola seed yield under field conditions. These studies underscore the need for good resistance stewardship and for the integration of multiple products and practices for successful management of clubroot on canola.

• The Korean Journal of Mycology
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• v.13 no.1
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• pp.23-26
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• 1985

Percentage of Bakanae infection of rice seedlings grown in nursery box was higher than rice seedlings grown in protected semi-irrigated nursery regardless of seed treatment. Rice seedlings grown in nursery box had higher Bakanae symptom ratio than that of the rice seedlings grown in protected semi-irrigated nursery in the paddy field conditions after transplanting. Grain yield of rice transplanted from nursery box was lower than that of the rice in protected semi-irrigated nursery.

• Journal of Ginseng Research
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• v.26 no.3
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• pp.151-158
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• 2002

Ginseng (Panax quinquefolius L.) has become one of the most valuable herb crops grown in North America. However, traditional cropping practices are favourable to disease and significant losses due to root disease are common, despite frequent use of fungicides. Seedlots are often contaminated with pathogens, however, little is known about the causes of seed decay and the role of seed pathogens as incitants of root rots. It was shown that both Fusarium spp. and Cylindrocarpon destructans were able to rot seeds and that C. destructans was more virulent than Fusarium spp. on seedling roots. A modified rose bengal agar MRBA) medium (1 g KH$_2$PO$_4$; 0.5 g MgSO$_4$; 50 mg rose bengal; 10 g dextrose; 5 g Bacto peptone; 15 g Bacto agar; 30 mg streptomycin sulfate; 250 mg ampicillin; 10 mg rifampicin; 500mg pentachloronitrobenzene; 500 mg dicloran; and 1 L distilled water) was superior to potato dextrose agar in detecting C. destuctans in diseased roots. Isolation of C. destructans from diseased seedlings arising from seeds sown in replant soil supported the hypothesis that this pathogen is a cause of ginseng replant failure in North America.

• The Korean Journal of Mycology
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• v.12 no.4
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• pp.171-174
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• 1984

To investigate the relationship between symptom development of Bakanae disease and yield component (the length of panicle, weight of panicle, number of healthy grain per panicle and number of panicle per hill), rice seedlings infected with F. moniliforme were transplanted. The number of panicles per hill and healthy grain per panicle were greatly decreased by the development of Bakanae symptom. Yield components was not correlated with the time of the Bakanae symptom development. Rice plants with Bakanae symptom had lower yield as 210g per 10 hills than healthy plants as 469g per 10 hills.

• Mycobiology
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• v.47 no.2
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• pp.135-142
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• 2019

Many members of the Saprolegniales (Oomycete) cause mycoses and disorders of fishes, of which Achlya and Saprolegnia are most ubiquitous genera worldwide. During a survey of the diversity of freshwater oomycetes in Korea, we collected seven isolates of Achlya, for which morphological and molecular phylogenetic analyses enabled them to identify as Achlya americana and Achlya bisexualis. In Korea, only a species of Achlya, A. prolifera, has been previously found to cause seedling rot on rice (Oryza sativa), but none of the two species have been reported yet. Importantly, A. bisexualis was isolated from a live fish, namely rice fish (Oryzias sinensis), as well as freshwater, and this is the first report of Achlya-causing mycoses on freshwater fishes in Korea. The presence of A. americana and A. bisexualis on live fish in Korea should be closely monitored, as considering the well-known broad infectivity of these species it has the potential to cause an important emerging disease on aquaculture industry.

• The Plant Pathology Journal
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• v.39 no.5
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• pp.513-521
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• 2023

Seed-borne diseases reduce not only the seed germination and seedling growth but also seed quality, resulting in the significant yield loss in crop production. Plant seed harbors diverse microbes termed endophytes other than pathogens inside it. However, their roles and application to agricultures were rarely understood and explored to date. Recently, we had isolated from soybean seeds culturable endophytes exhibiting in-vitro antagonistic activities against common bacterial and fungal seed-borne pathogens. In this study, we evaluated effects of seed treatment with endophytes on plant growth and protection against the common seed-borne pathogens: four fungal pathogens (Cercospora sojina, C. kikuchii, Septoria glycines, Diaporthe eres) and two bacterial pathogens (Xanthomonas axonopodis pv. glycines, Pseudomonas syringae pv. tabaci). Our experiments showed that treatment of soybean seeds with seed endophytes clearly offer protection against seed-borne pathogens. We also found that some of the endophytes promote plant growth in addition to the disease suppression. Taken together, our results demonstrate agricultural potential of seed endophytes in crop protection.

• Journal of Mushroom
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• v.13 no.1
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• pp.16-20
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• 2015

Water extracts from spent mushroom substrate (SMSE)of edible mushrooms, Pleurotus eryngii, Hericium erinaceus and Lentinula edodes promoted growth of pepper seedling. Mycellial growth rate of Phythopthora capsici and Fusarium oxysporum was dramatically inhibited by 100% and 70% on PDA added with SMSE of H. erinaceus. SMSEs from H. erinaceus, P. eryngii, and L. edodes effectively reduced the disease severity of Phytophthora blight of pepper caused by Phytophthora capsici to 75%, 10% and 35%, respectively. These results suggested that SMSE from the mushrooms have dual effects that suppress phythopthora blight disease and promote plant growth of pepper.

• Research in Plant Disease
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• v.20 no.2
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• pp.126-128
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• 2014

This study was carried out to assay the disease incidence degree of Sclerotium rot caused by Sclerotium rolfsii in sixteen most popular commercial cultivars of sweet potato (Ipomoea batatas) in Republic of Korea. The degree of disease incidence was evaluated on pot experiments. In pot experiments using artificial inoculation, the Sclerotium rolfsii caused a stem rot on seedling of sweet potato plants and causes a crown rot on lower stems near or at the soil line at favorable environmental conditions. White mycelial mats and sclerotia were formed at the infection sites. Plants severely infected were fell over or died because lower stems near soil surface were rotten. The degree of disease incidence was varied according to cultivars. Two cultivars, Bio-mi and Deayumi, were very resistant, while five cultivars, Shinjami, Shingeonmi, Hongmi, Yeonjami, and Shinhung-3 were highly susceptible.

• Research in Plant Disease
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• v.10 no.2
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• pp.112-116
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• 2004

This study was carried out to investigate factors affecting disease development of rice brown spot caused by Cochliobolus miyabeanus in the field and under the greenhouse conditions. In normal paddy fields, the pathogen was more frequently isolated from dried rice straws than wet straws after overwintering. The pathogen was also readily isolated from wet rice straws of salty paddy fields although infection rate of the fields was low. The disease symptom was first observed at 2 to 3days after inoculation when the seedlings were kept for 6 hours in dew chamber. The number of lesions peaked at 14 hr incubation in cultivars Chucheongbyeo and 24 hr incubation in cultivar Daesanbyeo and Tetep. Sixty three-d-old seedlings were more susceptible than 21 to 49-d-old seedlings regardless of cultivar. There was some difference in number of lesions observed, but the lesions were evenly spread regardless of leaf position. Light on the rice seedlings at 3,000 lux or 6,000 lux showed more severe symptoms than those in the dark.