• Research in Plant Disease
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• v.30 no.2
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• pp.181-188
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• 2024

Southern blight, caused by the soil-borne fungus Sclerotium rolfsii, is a serious disease that affects many economically important crops. In this study, we selected Bacillus subtilis GJ6-14, from a total of 260 strains, to control Southern blight in pepper plants. In both seedling and plant tests, GJ6-14 significantly suppressed disease incidence and severity compared to control, furthermore, GJ6-14 demonstrated efficient colonization in the rhizosphere by maintaining the population from log 5.41 to log 3.92 in the pathogen-inoculated plants, indicating its potential as a biocontrol agent. Molecular analysis revealed up-regulation of defense-related genes, such as a 7.6-fold increase in LOX1 and 15.5-fold increase in PR1, at 72 hr after inoculation of S. rolfsii in GJ6-14-treated plants, suggesting activation of plant defense mechanisms. Overall, our findings highlight the promising role of B. subtilis GJ6-14 as a potential biocontrol agent in sustainable management of Southern blight in pepper plants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.328-333
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• 1983

Due to fast industrialization and reduced agricultural population, there has been increased farm mechanization to reduce the labor requirement. In rice production, mechanical transplanting has been increasingly popular due to the heavy labor requirement in hand transplanting and development of convenient transplanters. For mechanical transplanting, rice seedlings is grown in boxes with limited soils under super dense population, thus short period of exposure to unfavorable temperature and poor water management would cause severe damage to rice seedlings such as seedling damping off and the similar physiological disorders. Several chemicals were evaluated for their effectiveness to control the disease and disorders, and other effects as plant growth stimulants. 3-hydroxy-5-methylisoxazole-a soil fungicide, Metalozyl-a fungicide which controls mildew, SF 8002-the composite of above two chemicals, and Isoprothiolane-a fungicide which controls rice blast were found to be effective controling seedling damping off and similar physiological disorders, and improvement of physiological characteristics of the seedlings such as the amount of bleeding sap, rooting ability, negative geotrophism, and regrowth after cutting. The results indicated that the chemicals will be very effective raising healthy seedlings even under unfavorable environments by the improvement of physiological activities of seedlings and preventing seedling damping off and the similar physiological disorders.

• The Korean Journal of Mycology
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• v.31 no.1
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• pp.44-49
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• 2003

Several microbial biocontrol products (Greenbiotech Co., Paju, Korea), Green-all T (Trichoderma harzianum), Green-all S(Bacillus sp.) and Green-all G (Streptomyces sp.) were supplemented with organic amendments such as sawdusts and rice hulls to study on efficacy of biological control of seeding damping-off of cucumber caused by Pythium ultimum. Sawdusts amended into potato dextrose agar alone could inhibit in vitro mycelial growth of P. ultimum. All there microbial products of Green-all T, Green-all G and Green-all S significantly reduced seeding damping-off (LSD, P=0.05). However, several amendments such as sawdusts and rice hulls into Green-all T and Green-all S products did not increase efficacy of biological control compared to non-amended treatment. In contrast, supplements of aminodoctor containing several amino acids (Greenbiotech Co., Korea) into Green-all G product significantly increased efficacy of biological control of seeding damping-off, resulting in from 42% to 2% disease incidence in relation to seedling emergence (LSD, P=0.05). Also, amendment of sawdusts into Tricoderma product significantly increased efficacy of biological control as disease index of 5.0 compared to non-amended control of 56.0 in Green-all T product alone. This indicates that organic amendments could increase efficacy of biological control of cucumber seedling damping-off.

• The Plant Pathology Journal
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• v.28 no.3
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• pp.311-316
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• 2012

Fusarium root disease can be a serious problem in forest and conservation nurseries in the western United States. Fusarium inoculum is commonly found in most container and bareroot nurseries on healthy and diseased seedlings, in nursery soils, and on conifer seeds. Fusarium spp. within the F. oxysporum species complex have been recognized as pathogens for more than a century, but attempts to distinguish virulence by correlating morphological characteristics with results of pathogenicity tests were unsuccessful. Recent molecular characterization and pathogenicity tests, however, revealed that selected isolates of F. oxysporum are benign on Douglas-fir (Pseudotsuga menziesii) seedlings. Other morphologically indistinguishable isolates, which can be virulent, were identified as F. commune, a recently described species. In a replicated greenhouse study, inoculating Douglas-fir seedlings with one isolate of F. oxysporum prevented expression of disease caused by a virulent isolate of F. commune. Moreover, seedling survival and growth was unaffected by the presence of the F. oxysporum isolate, and this isolate yielded better biological control than a commercial formulation of Bacillus subtilis. These results demonstrate that an isolate of nonpathogenic F. oxysporum can effectively reduce Fusarium root disease of Douglas-fir caused by F. commune under nursery settings, and this biological control approach has potential for further development.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.212-226
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• 2002

North American ginseng production may have been maximized in the traditional growing areas in the last decade and further increases may be in woods grown root, for niche markets. The marketplace demands high quality roots. Most problems leading to low quality roots start with the grower and can be avoided. These include poor site selection, inadequate soil drainage, untimely and poorly applied pesticides, and neglect of good sanitary practices. Selection of low lying sites increased the plant damage from frost in Ontario in May 2002. Seeding is still the major method of propagation of ginseng in spite of some success in culturing different parts of the plant. Opportunities exist for shortening the stratification period of North American ginseng seed to allow spring planting. This may reduce disease incidence. Since only one-third of ginseng seed sown ultimately produces plants harvested after 3 years any approach that reduces disease incidence and improves seed germination, seedling emergence and crop stand must be pursued. Disease is the major problem in ginseng cutivation from seed stratification, soil preparation prior to planting, right through to drying of the roots. Replant disease remains as an unresolved problem and needs full characterization and new approaches for control. Much progress has been made in research and related extension activities in disease control although challenges will arise such as with Quintozene and its replacement with Quadris for control of diseases caused by Rhizoctonia. Decreased labor populations and increased associated costs for ginseng production are causing rapid mechanization in every aspect of the ginseng industry. Engineers, machinery dealers, and fabricators, and growers are being challenged to increase efficiency by mechanization.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.413-420
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• 2013

The purpose of this study was to evaluate the control efficacy of major environment-friendly control agents against powdery mildew, as affected by the application condition such as disease-developing stage and microclimate, as compared with the efficacy of pesticides in plug seedling of three Cucurbitaceae vegetables, including cucumber, melon, and oriental melon. Single or combined application of major six environment-friendly control agents was used in the experiment: two biofungicide (Ampelomyces quisqualis 94013 and Bacillus subtilis Y1336), two plant extracts (neem oil and extracts of Rheum undulatum), and two mineral materials (wettable sulfur powder and lime bordeaux mixture). These control agents were treated to the plug seedlings for preventing powdery mildew and curative applications for managing powdery mildew. In all treatments, the disease incidence declined as daily average temperatures increased to $30^{\circ}C$ for consecutive 6~8 days with maximum temperature over $40^{\circ}C$. In preventative application, the control efficacy against powdery mildew was the highest in the treatment of wettable sulfur powder, and lowest in the B. subtilis Y1336, with values of 20~40%. In cucumber seedlings, the preventive single application of neem oil or wettable sulfur powder was more effective than curative application of fungicides, while the control efficacy of these agents was similar to those of fungicides in melon seedlings. The single application of R. undulatum extracts was also effective in preventing the disease for both cucumber and melon seedlings, showing a higher control efficacy than those of biofungicides during seedling stage. The treatment of water spray was not effective and showed a higher disease incidence than the untreated control plot in the oriental melon and melon seedlings. The curative application with environment friendly control agents, after powdery mildew was first detected, could not successfully controlled the disease at the middle stage (5~10% of disease incidence) of disease development. The curative combined application of [R. undulatum extracts (1st application) + wettable sulfur powder (2nd) + neem oil (3rd)] showed the highest control efficacy among the other treatments, with control value over 80% at the early stage (less than 1% of disease incidence) of disease development.

• Korean Journal of Medicinal Crop Science
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• v.9 no.3
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• pp.211-219
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• 2001

The disease incidence rates of Phytophthora root rot of A. macrocephala caused by P. drechsleri were dramatically increased in two distinctive periods at experimental fields of National Crop Experiment Station(NCES), Suwon, in 1999 and in 2000 ; one was in the period of 30 to 45 days old seedling stage in spring and the other was just after heavy rainy season in late summer or in early fall. The disease was occurred at seedling stage under the conditions of ${{\geq}15^{\circ}C}$ of average temperature with ${{\geq}100mm}$ rainfalls for 20 days and the tendencies were similar in both year. By the disease, rhizome propagated field was more damaged(18.6%) than seed propagated field(56.0%). Comparing the disease incidence rates at five different fields in Suwon, Youngju and Andong, the damages at soil improving fields and non-mulching fields were less severe than those at continuous cropping fields without soil improvement and mulching fields and occurrence. Expansion of the disease were seemed to be highly related with the populations of P. drechsleri in soils depend on the cultivation method and field conditions. Although the populations of the pathogen in soils collected from Andong and Youngju, in which rhizome were continuously propagated for two and three years respectively, were comparably less than that from Suwon, in which rhizome were propagated for one year, however, the damages by the disease were more severe in Andong and Youngju. So, two or more years of cultivation at the same field may not be useful for Atractylodes plants..

• Korean Journal of Microbiology
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• v.1 no.1
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• pp.45-47
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• 1963

1. A Kind of Bacillus, which was seemed to be pathogenic, was isolated from Pinus rigida planting. 2. The bacillus were grown well on the Agar-Bacto-Beef media (pH 7.4) at $30^{\circ}C$. C for 24 hours. 3. The soil infection for the one year old seedling was the best inoculating method in this experiment. 4. Almost of all characteristics were simillar between isolated and reisolated bacillus. 5. The author should like to call temporarily the name of this bacterial disease Stem-rot of pinus rigida Mill.

• Plant Disease and Agriculture
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• v.5 no.1
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• pp.8-13
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• 1999

Twenty two different disease on strawberry have been reported in Korea. Their occurrence patterns were depended on the varieties cultivated. Fusarium wilt occurred seriously on var. Hokowase, a variety used for the fields or semi-forcing culture. In recent years, however, anthracnose occurred remarkably as the acreage of forcing culture increases. Consequently, anthracnose reduced the stand rate and yield of the strawberry. Average occurrence rate of anthracnose was 36.9% on major strawberry cropping areas. Nyoho and Akihime, which are popular varieties for the forcing culture, are considered to be susceptible, but Holiwase and Suhong are resistant against this disease. Colletotrichum gloeosporioides and Glomerella cingulata have been reported as casual agents for this disease in Korea. C. gloeosporoides was recently reported, but C. fragariae, known to be a strong pathogen in foreign countries, has bot been found yet in Korea. These two fungal pathogens showed significant differences in some characteristics such as major infection parts of plant and responses to temperatures as well as benomyl resistance. In addition, C. gloeosporioides is more pathogenic than G. cingulata. Because vinly sheltering is effective for control of anthracnose to protect water disposal of the pathogen during the seedling stages, it is strongly recommend to use this method in conjunction with integrated control programs.

• Plant Disease and Agriculture
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• v.5 no.2
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• pp.90-94
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• 1999

Effect of inoculum concentration inoculation method and plant age on development of clubroot disease of Chinese cabbage seedling were examined in growth chambers. Root galls were developed at the concentration of 105 resting spore or above per ml of incoulum and as the inoculum concentration became higher rate of development of root galls was faster. In the plants with root gall development fresh weight of above ground parts was reduced to 30-44% of that of healthy plants but root weight increased by 4-10 times. Growth of diseased plants was greatly reduced as compared to healthy plants. Planting in the diseased soil as a inoculation method was most effective for disease development showing uniform infections but time of initial root gall development was delayed by root soaking inoculation. Some plants inoculated by soil drenching method did not develop root galls. However root gall enlargement after its initial formation did not differ greatly among inoculation methods. Nine-day-old seedlings showed poor development of root gall but 16-days-old seedlings was found to be most adequate for inoculation for gall development.