• Research in Plant Disease
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• v.18 no.4
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• pp.338-348
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• 2012

Potato late blight caused by Phytophthora infestans Cooke is one of the major diseases in the cultivation of potatoes in Korea. Effect of chitosan preparations (SH-1 and SH-2) was evaluated on the inhibition of mycelial growth of P. infestans, and protective activity using detached potato leaf assay both in vivo and in the field test. SH-1 and SH-2 were showed protective activity of young plant with control values more than 95% potato late blight by inoculation with pathogens under growth chamber conditions. Mycelial growth was inhibited the radial growth over 74% at a concentration of $300{\mu}g/ml$ of both SH-1 and SH-2. Spraying with SH-1 and SH-2 on the leaves for detached leaf assay reduced disease development. The content of total polyphenol in stem was significantly increased by SH-1 and SH-2 application in the field. In field experiments, foliar application with both SH-1 and SH-2 were significantly reduced the development of late blight on potato plants. Control of late blight disease was obtained with control values of 72% and 53% by application of 1% SH-1 and SH-2, respectively, with 4 times at 7 days interval, and reduced with similar disease control values by application with 3 times at 14 days interval compared with untreated control. SH-1 and SH-2 applications increased the fresh weight of potato, and higher grade potatoes were also increased. The results showed that SH-1 and SH-2 applications can be used as eco-friendly natural fungicide for organic farming for the increase of yields and control of late blight.

• The Korean Journal of Pesticide Science
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• v.12 no.4
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• pp.351-356
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• 2008

This study was carried out to assess adoptability and environment impacts of ultra low volume (ULV) pesticide spray solutions aerially sprayed by manned-helicopter. Uniformity of the deposited amount in paddy fields was uneven, showing $3.1{\sim}4.7$ times differences among surveyed sites. Drifting distance of aerially sprayed droplets from the target area was within 30 m in the wind direction and 20 m in the opposite direction. Most of the aerially sprayed pesticides were deposited in/on rice plants, while those in submerged paddy water and soil were relatively small. The degradation rate of the deposited pesticides was in the decreasing order of rice plants, paddy water and soil. Soil residues of pesticides in the aerially sprayed rice paddy fields after harvest ranged from non-detected to 0.201 mg/kg. However, no pesticides were detected in brown rice and rice straw. No phytotoxic symtoms were observed in rice plants and nearby non-target crops by the sprayed pesticides.

• The Bimonthly Magazine for Agrochemicals and Plant Protection
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• v.8 no.4
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• pp.101-109
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• 1987

포도나무에 발생하는 병(病)은 현재 19종(1986)이 알려져 있으며, 병 발생의 중요도가 여러 가지 요인의 변화에 따라서 바뀌고 있다. 그 요인을 우선 약제사용면에서 보면 약제종류의 변화, 살포방법의 변화, 살포회수의 변화 및 포장위생의 불철저 등을 들 수 있고 재배적인 면에서 보면 품종의 변천, 재배형의 변화, 시비방법의 변화 등을 들 수 있다. 또 해와 지역에 따라서는 이상저온, 다우다습(多雨多濕), 건조 등 기상 조건이 변함에 따라서도 병의 발생은 크게 달라 진다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.07a
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• pp.363-369
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• 2002

시비작업은 농업작업 중에서도 매우 복잡하고 까다로운 작업에 속한다. 엽색, 무성정도를 육안으로 보면서 과거의 경험, 논과 포장별 이력, 품종, 기상조건 등을 고려하여 시비시기, 시비량을 적기에 판단ㆍ결정하지 않으면 안 된다. 게다가 비료주기에서는 포장내 생육을 고려하여 위치에 따라 필요한 만큼 적정량을 살포해야 한다. 넓은 포장 안에서는 위치별로 생육차이가 있으므로 이러한 생육변이에 따라 시비량을 가감해야 하는 매우 복잡한 조작을 포함하고 있다. (중략)

• Korean Journal of Organic Agriculture
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• v.24 no.1
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• pp.123-130
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• 2016

The mortality was tested to organic control materials to the E. maslovskii adults by the dipping method in laboratory. As the result, in 2014, the extracts of Neem I was not shown control effect by 10.2% control efficacy to E. maslovskii adults in laboratory. The extract of Sophora flavescens roots was shown 84.7% mortality. And other 5 materials were shown 100% insecticidal activity to the adults in laboratory. I n 2015, Plant extract+pyrolignous acid Matrine 0.45% and Plant extract Matrine 0.5+paraffin oil 8% were shown 100% and 94.6% control efficacy, respectively. In the Japanese apricot orchards, the fruit damage rate was low on spray at 21th April in Daap, Gwangyang city, and 8th May Hwangjeon, Suncheon city in Jeonnam province in 2014. The fruit damage rate differed from spray timing and materials, but it was considered that the control of E. maslovskii should be in late April to early May. Otherwise, in 2015, the fruit damage was significantly low in late April spray in Daap, but no significant was in between one spray at 21th, 27th April and 2 spray that days. Meanwhile, the control effect was better 2 times spray of the days in Hwangjeon, Suncheon city in Jeonnam province. Therefore, in organic Japanese apricot, the use of insecticidal materials recommended to control over twice spay in from meddle to late April.

• Research in Plant Disease
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• v.13 no.1
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• pp.40-44
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• 2007

Powdery mildew of pepper is one of the most devastating diseases which is occurring all the year under greenhouse condition. In this study, control efficacy against powdery mildew was evaluated by mixed culture solutions of two chitinolytic bacteria, Lysobacter enzymogenenes strain C-3 and Chrornobacterium sp. strain C-61, cultivated in the chitin-supplemented medium. In all experiments, white powder on the reverse side of pepper leaves perfectly disappeared 3 days after application of mixed culture solutions. However, periods required for formation of new white powder on the same sites after application (control-lasting period) were largely differed according to environmental conditions. In particular, the control-lasting period was much longer when sprayed on 6 PM than 9 AM and especially, on rainy days than sunny days. This indicates that control efficacy of culture solution may be largely affected by environmental conditions after application. The undiluted culture solution resulted in a perfect control with control value more than 95% by application of 5-day-intervals under severely diseased field and 7-day-intervals under disease-started field. A ten-fold diluted product also showed control value more than 81% by application of the same method. These results suggest that this culture solution can be practically used to control powdery mildew disease in pepper plants.

• Research in Plant Disease
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• v.14 no.1
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• pp.37-42
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• 2008

Bacillus subtilis BD0310 isolated from tea leaves was used for the development of a biofungicide against Pestitalotiopsis longiseta causing gray blight of tea plants. After mass culture of the antagonistic bacteria, the biofungicide formulated as a suspension concentrate was evaluated for its control efficacy against the gray blight of tea plant in a greenhouse and a tea plantation, respectively. Spray of the biofungicide 2 days before inoculation of P. longiseta inhibited more efficiently the development of gray blight compared with spray of the biofungicide 2 days after inoculation of the pathogen onto the leaves of tea plants in a greenhouse. In the field investigation under application of the biofungicide in 2005 and 2006, control efficiencies increased according to the number of spray of the biofungicide. Control efficiencies of the biofungicide were 52.4%, 66.7%, 71.4% and 85.7% against gray blight in 4 times spray of the biofungicide alone at 7 days interval, 6 times spray of the biofungicide alone at 7 days interval, 2 times alternate spray of biofungicide and chemical fungicide at 7 days interval and 4 times spray of chemical fungicide alone at 7 days interval, respectively. Therefore, the alternate application of the biofungicide and chemical fungicide at 7 days interval can increase the control efficiency with reduction of the amount of chemical fungicides and the number of spray for the control of gray blight of tea plants in the field.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.293-299
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• 2002

This experiment was conducted to elucidate the effects of fruit bagging on the amounts of pesticide residues on/in pears with two pesticides, chlorpyrifos 25% WP, and penconazole 5% WP, and two pear cultivars, Niitaka and Hwangeum-bae. Residues of chlorpyrifos and penconazole in bagged pears were only $0.4{\sim}27%$ of those in non-bagged one. Residues of both pesticides in bagged and non-bagged pears were steeply reduced in the field but slowly reduced during storage. Residues of chlorpyrifos were more in the peel than in the flesh, while penconazole in bagged pear was evenly distributed in the peel and flesh. Chlorpyrifos was evenly distributed in outer bag and inner bag irrespective of bag materials, while most of penconazole was found in outer bag rather than in inner bag. To produce safer pear from pesticide residues, removal of bag before storage is recommended.

• Korean journal of applied entomology
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• v.42 no.2
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• pp.153-157
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• 2003

This experiment was conducted to investigate control effect of Spodoptera litura using nucleopolyhedrovirus in chrysanthemum seedlings of open field and plastic house. Values of LT$_{50}$ of treatment 1.0$\times$10$^{6.8}$ PIBs/ml were 6.2-5.1 days in open field and 6.9-5.4 days in plastic house. Values of LT$_{50}$ and LT$_{95}$ were shorter in open field than in plastic house. Cumulative mortality was 100% in 1.0$\times$10$^{7.8}$ PIBs/ml and also higher in open field than in plastic house. In chrysanthemum field, organic synthetic insecticide (endosulfan EC) killed S. litura larvae in 2 days after application. Motality of S. litura larva inoculated with S. litura nucleopolyhedrovirus (SINPV) 1.0$\times$10$^{6.8}$ PIBs/ml was found out from 4 days after application and maintained during 14 days. Protection values of with SINPV 1.0$\times$10$^{8}$ PIBs/ml after 16 days were 94.0% and 89.4% in open field and plastic house, respectively, and those of endosulfan 350 ppm were 91.4% and 88.6%, respectively.

• Research in Plant Disease
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• v.10 no.1
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• pp.82-85
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• 2004

Bacterial soft rot by Erwinia carotovora subsp. carotovora is one of the diseases causing the biggest damages in Chinese cabbage cultivation. This study was conducted to evaluate on suppressive effect of calcium fertilizer to bacterial soft rot of Chinese cabbage. Seven calcium fertilizers were selected for evaluation. And screening was conducted to select effective agents for controlling bacterial soft rot. When applied by the nursery test condition using mineral oil inoculation method with Chinese cabbage, calcium hydroxide had more suppressive efficacy than any other calcium fertilizer, While nitrogen fertilizer was induced the disease, calcium hydroxide was suppressed soft rot disease in field test as well as seedling test. Treatment of calcium+nitrogen fertilizer as well as calcium only showed a significant control effect in the field experiment with Chinese cabbage 'Sanchon' in 2003.