• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.509-516
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• 2023

The use of sulfur(S) in concrete has been variously studied as a way to improve salt resistance in concrete. However, sulfur is a solid material and is difficult to powder, which has disadvantages in its usability as an admixture or mixture for cement and concrete. For these problem, polymers such as dicyclopentadiene have been used to modify sulfur, but this also exists in a sticky state after modifying and does not improve the fundamental problem. So, reforming sulfur with slaked lime and the effect on cement hydration was examined by reforming sulfur with slaked lime, and the following conclusions were obtained. Depending on the reaction conditions, slaked lime modified bio-sulfur exists in a slurry state containing unreacted sulfur, unreacted slaked lime, calcium-sulfur(Ca-S) compounds and water. When slaked lime modified bio-sulfur is used as a cement mixture, salt resistance of concrete with slaked lime modified bio-sulfur is to be superior to that of plain concrete. This is believed to be because structure of cement hydrates with slaked lime modified bio-sulfur is to be more dense to that of plain cement hydrates by the continued presence of ettringite and can be used as a cement mixture in concrete.

• Korean Journal of Organic Agriculture
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• v.28 no.2
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• pp.223-233
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• 2020

The aim of the present study was to investigate the suppressive effects of the bio-sulfur used by eco-friendly farms on the outbreak of citrus scab. To evaluate the inhibiting effect of bio-sulfur on citrus scab germ tube growth, the citrus scab pathogen Elsinoe fawcettiiwas cultured in PDB and agar media, and germ tube growth was observed after bio-sulfur treatment. At both 40 and 88 h after inoculation, germ tube formation was inhibited by 500-, 1000-, and 2000-fold diluted bio-sulfur, and at dilutions above 4000-fold, germ tube formation was observed, although growth was still inhibited, when compared to untreated cultures. Meanwhile, the occurrence of citrus scab on spring-flush leaves in the field was 40.3% in the untreated control and 5.3, 10.3, 12.3, 15.3, and 24.0% when treated with imibenconazole, 2-4 and 6-6 lime-Bordeaux mixtures, which are also used by eco-friendly farms, 500-fold diluted bio-sulfur, lime sulfur, and 1000-fold diluted bio-sulfur, respectively. The occurrence of citrus scab on citrus fruit was 79.3% in the untreated control and 4.0, 33.8, 42.0, 43.3, 44.8, and 78.0% when treated with imibenconazole, 2-4 lime-Bordeaux mixture, 6-6 lime-Bordeaux mixture, 500-fold diluted bio-sulfur, lime sulfur, and 1000-fold diluted bio-sulfur, respectively. Because citrus scab can infect citrus leaves as early as May, as the spring flush begins, preventative control should be implemented by mid- to late-April, thereby increase disease control and reducing both labor and farming costs.

• Korean Journal of Organic Agriculture
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• v.25 no.1
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• pp.125-134
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• 2017

This study was carried out to examine the effects of soil sulfur mixture on the control apple valsa canker in apple orchard for two years. In organic apple orchard, The recovery percentages of apple valsa canker were compared among control (no treatment), lime sulfur, and soil sulfur in organic orchards. In conventional apple orchards, those of recovery percentages were compared among control, neoasozin, lime sulfur, and soil sulfur. Compared with control, soil sulfur treatments significantly improved the recovery percentages of apple valsa canker infected trees in organic orchard. However, there were no differences between lime sulfur and soil sulfur treatment in organic apple orchard, except BongHyun orchard experiment in 2013. Compared with control fruit qualities, fruit skin red color and fruit firmness were improved in lime sulfur and soil sulfur treatment, respectively. In conventional orchard, apple trees treated with lime sulfur, soil sulfur or neoasozin improved recovery percentages, compared with those of control trees. Soil sulfur treatments recovered 87.5~97.5% of infected 'Fuji'/MM106 apple trees in organic and conventional apple orchards. The trees applied with neoasozin showed significant lower shoot growth than those of soil sulfur treatment in conventional orchard. Soli sulfur treatment improved fruit red color, but did not affected fruit weight, fruit firmness, soluble solids concentrations, and titratable acidity.

• Research in Plant Disease
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• v.24 no.1
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• pp.52-58
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• 2018

Pear scab and rust are the major diseases causing severe epidemics in organic cultivation of pear trees. Incidences of pear scab and rust were compared in organically managed plots and conventionally managed plots to obtain optimum application schedule of environment-friendly control agents in organically managed plots. Organically cultural practice with 10 time-applications of lime sulfur and Bordeaux mixture showed higher than 40% of control efficacies of pear scab and rust compared to conventionally cultural practice. Organically cultural practice with 8 time-applications of lime sulfur considering weather condition showed higher than 30% of control efficacies of pear scab compared to conventionally cultural practice. The results suggest that proper application of environment-friendly control agents such as lime sulfur considering weather condition will enable effective control of the major diseases for organic cultivation of pear.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.371-382
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• 2023

This study aimed to estimate optimal treatment for enhancing the germination rate and disinfections effect of organic wheat varieties, Jokyung, Geumgang, Saegumgang, and Baekgang using hot water treatment and lime sulfur mixture. Before disinfection, the germination rates of the seeds averaged 86.3±2.5% to 87.5±2.9%, while the infection levels caused by fungi and bacteria were observed to be 22.5±2.9% to 38.3±2.5% and 18.8±4.8% to 23.8±2.5%, respectively. The germination rates of four wheat varieties under hot water treatments were either the same or higher compared to untreated seeds. As the temperature and treatment time of hot water treatment increased, the contamination levels of fungi and bacteria decreased. The optimal hot water treatment for the seeds was observed at 55℃ for 10 minutes, resulting in germination rates averaging 90.0±0.0% to 97.5±2.9%, which were either the same or higher than untreated seeds. The disinfection effectiveness against fungi and bacteria was high, averaging 83.3~93.5% and 100%, respectively. Additionally, an investigation was conducted on the germination rates and microbial disinfection efficacy of 0.2% and 0.4% lime-sulfur mixture with varying treatment times, 3 to10 minutes for each wheat variety. As the treatment time elapsed, no significant differences in germination rates were observed among four wheat varieties. However, the germination rates were higher compared to the untreated group (86.3~87.5%), and the optimal treatment time was found to be 7 minutes or 10 minutes, resulting in an average reduction of 90.0~96.0% in contamination levels of fungi and bacteria. Therefore, the germination rates and disinfection effects varied depending on the treatment conditions of hot water treatment and lime-sulfur mixture applied for the disinfection of the four varieties of organic wheat seeds. However, it is considered that treating the seeds with hot water treatment at 55℃ for 10 minutes or with 0.2% or 0.4% lime-sulfur compound for 10 minutes enhances germination rates and reduces the contamination rate of fungi and bacteria compared to untreated seeds. Thus, these environmentally friendly seed disinfection technologies are likely to be highly useful in agricultural fields.

• Journal of agriculture & life science
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• v.53 no.3
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• pp.27-39
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• 2019

The purpose of this study was to investigate the effect of hot water treatment and pH corrected lime sulfur combination treatment on the fungicidal and bacterial disinfection effects and germination rate of organic lettuce seeds. Among the followers, Alternaria sp. was infected 53.3% and Aspergillus sp. and Cladosporium sp. Infected 14.5% and 5.4%, respectively. Bacteria were isolated only Pseudomonas sp., and infected with 16.5%. In order to investigate the effect of disinfection on the temperature of hot water (45℃, 50℃, 55℃ and 60℃). The seed germination rate sharply decreased with increasing temperature and treatment time. The germination effect and germination rate of the follower were highest when hot water treatment was carried out for 20 minutes in hot water at 50℃. In the case of combined treatment of 50℃ hot water for 10 min and 0.4% pH adjusted lime sulfur mixture, showed the highest sterilization effect and germination rate with 100% and 97.6%, respectively. The results of this study can contribute to the development of technology to sterilize not only seed surface but also fungi and bacteria inside of seed.

• Korean Journal of Agricultural Science
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• v.5 no.1
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• pp.7-14
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• 1978

The experiment was carried out in order to choose fungicides which are proper to be used in flowering time of fruit trees. The effect of fungicides on pollen germination and pollen tube growth was investigated in vitro. The results obtained are as follows : 1. Difolatan-Wp, Lime-sulfur, Captan-Wp and Bordeaux mixture greatly inhibited pollen germination and pollen tube growth. 2. The effect of Daconil-Wp and Zimaneb-Wp on pollen germination and pollen tube growth was not so great as that of Difolatan-Wp, Lime-sulfur, Captan-Wp or Bordeaux mixture. 3. Polyram-combi-Wp, Topsin-Wp and Benlate-Wp did not affect pollen germination but these fungicides slightly inhibited pollen tube growth. 4. Polyoxin-Wp significantly increased pollen tube growth but did not show promotive effect on pollen germinaiton.

• Horticultural Science & Technology
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• v.34 no.5
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• pp.708-718
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• 2016

Two different pest control programs were applied on 8-year-old 'Ryoka'/M.26 apple trees (Malus domestica Borkh.). Lime sulfur or Bordeaux mixture with emulsified oil were applied 12 times from late March to mid-September as organic treatment, and synthetic chemicals were 7 times applied as control treatment. Over the entire apple-growing season, photosynthesis rates of apple trees were significantly lower in the organic treatment than in the control, and this photosynthetic differences were larger in July and August. Photosynthesis-related parameters such as stomatal conductance and transpiration behaved similarly to photosynthesis. The leaf area in the organic treatment was significantly smaller ($24.7cm^2$) than that in the control treatment ($30.7cm^2$). Organic leaves contained significantly less Chl. a ($15.5mg{\cdot}g^{-1}$) than did control leaves ($17.6mg{\cdot}g^{-1}$). Fruit yield per tree was significantly lower in the organic treatment (18.8 kg) than in the control (24.5 kg), because organic fruits experienced a higher rate of disease infection such as white rot (Botryosphaeria dothidae) and bitter rot (Glomerella cingulata) than did control fruits. Organic fruits had high flesh firmness but less color development (lower Hunter's a values). In this experiment, the pest control program with frequent applications of organic fungicides showed negative effects on photosynthesis and disease infection on leaves and fruits, and thus reduce the fruit quality and yield in 'Ryoka'/M.26 apple trees.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.445-460
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• 2017

This study was carried out for three years from 2013 to 2015 to investigate the actual condition of pest control of domestic persimmon organically cultivated farmers, to select environment - friendly pest control materials for major pests, and to conduct field test of established control system. The main cultivated cultivar of the reader farmer of organic cultivation was "Buyou" and sprayed organic agricultural material 9~17 times per year for pest control. The most harmful pests were anthracnose, bugs, persimmon fruit worm, and scales, etc. The control materials used were organic lime sulfur mixture, red clay sulfur, emulsifier, bordeaux solution, and self-made plant extracts using garlic, ginkgo nut and pine tree. The effective materials for controlling anthrax were lime sulfur mixture and red clay sulfur. Garlic oil + citronella emulsion, shrubby sophora seed extract + tea extract was effective to control Riptortus clavatus and Euproctis subflava. When installed 60 ea per 10a of mating disruption trap in a sweet orchard, the fruit setting rate was improved by 30%. The results of field test of control system to control 10 times a year in organically grown persimmons were able to harvest fruit of 70.7%. However, since any kinds of pesticides can not be sprayed during the harvest season in September and October, the damaged by bugs did not decreased, and further research is needed.

• 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.