• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.329-336
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• 2014

As an abiotic stress, chilling stress is one of the major factors limiting plant growth and increasing susceptibility to pathogens. Therefore, enhancing stress tolerance in plants is an important strategy for their survival under unfavorable environmental conditions. The objective of this study was to determine the effects of the exogenous application of salicylic acid (SA) or nitric oxide (NO) on chilling tolerance in pepper seedlings. Pepper (Capsicum annuum L. 'kidaemanbal') seedlings were grown under normal growing conditions ($20/25^{\circ}C$, 15 hours photoperiod, $145{\pm}5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, fluorescence lamps) for 23 days after transplanting. The solution (3 mL) of 1 mM SA and 0.3 mM NO with surfactant triton 0.1% were sprayed two times a week, respectively. Right after the completion of chemical application, seedlings were subjected to chilling condition at $4^{\circ}C$ for 6 hours under dark condition and then the seedlings were recovered at the normal growing conditions for 2 days. In order to assess plant tolerance against chilling stress, growth characteristics, chlorophyll fluorescence (Fv/Fm), and membrane permeability were determined after chilling stress imposition. Total phenolic concentration and antioxidant capacity were measured during the whole experimental period. Disease incidence for pepper bacterial spot and wilt was also analyzed. Pepper seedlings treated with SA or NO were maintained similar dry mass ratio, while the value in control increased caused by chilling stress suggesting relatively more water loss in control plants. Electrolyte leakage of pepper seedlings treated with SA or NO was lower than that of control 2 days after chilling treatment. Fv/Fm rapidly decreased after chilling stress in control while the value of SA or NO was maintained about 0.8. SA increased higher total phenolic concentration and antioxidant capacity than NO and control during chemical treatment. In addition, increase in total phenolic concentration was observed after chilling stress in control and NO treatment. SA had an effect on the reduction of bacterial wilt in pepper seedlings. The results from this study revealed that pre-treatment with SA or NO using foliar spray was effective in chilling tolerance and the reduction of disease incidence in pepper seedlings.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.2
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• pp.24-34
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• 2000

The project for rehabilitation and revegetation of the abandoned coal-mine lands is a very important national environmental restoration project in the view point of rehabilitation and revegetation of denuded forest-lands caused by coal mining as well as restoration of disturbed natural environment and control of the variable pollutions. In Korea, because a large number of coal mines had been developed in order to fill up abundantly consumption of coal as a major energy source in the developing period, a lot of denuded forest-lands caused by coal mining had distributed in the whole country. And, due to the absence of effective rehabilitation and revegetation works on the denuded forestlands caused by coal-mining, most of them had been remained with being damaged. In 1990, area of the abandoned coal-mine lands, requiring the rehabilitation and revegetation works, was about 1,437.1 ha. For the past ten years ('90~'99), about 1,081.8 ha out of them had been rehabilitated and revegetated, and the rehabilitation planning area was about 33.0 ha in 2000. So, remaining area out of abandoned coal-mine lands will be about 322.3 ha after 2000. In principle, after abandoning coal-mine, mine owners must carry out the rehabilitation and revegetation works on the abandoned mine lands by themselves. But, most of mine owners were in financial difficulty after abandoning coal-mine, so that principle couldn't have obtained the desired effects. To solve this problem, from 1995, Coal Industry Promotion Board (CIPB) have carried out the rehabilitation and revegetation works on the abandoned coal-mine lands at government budgets, and they have obtained good results in the construction area. However, due to application of the "conventional erosion control measures and techniques" to the rehabilitation and revegetation measures on the abandoned coal-mine lands, the results and effects of the works excuted have not been successful. Therefore, unique measures and techniques for rehabilitation and revegetation of the abandoned coal-mine lands will have to be developed, especially including development of new techniques on the soil-dressing and soil-covering, seed spray and hydro-seeding measures with seed-fertilizer-soil materials as the mechanized measures, and using of new materials for the tree planting and seedling measures.

• The Korean Journal of Pesticide Science
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• v.17 no.3
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• pp.213-219
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• 2013

This study focused on the promotion of the insecticidal activity of eco-friendly insecticidal materials against four major insect pest in the organic Chinese cabbage cultivation area. Among insecticidal materials mixture, BT+Matrine+Neem against leaf beetle larva, Phaedon brassicae, showed the highest 94.1% at 0.05% which is the lowest concentration of three treated concentrations. The insecticidal activity of Matrine, Neem, and BT alone (0.1%, w/v) or the mixtures (0.05%, w/v) against Cabbage worm larva, Artogeria rapae, was investigated by leaf disc spray method. The insecticidal efficacy of the mixtures of two or three eco-friendly materials was higher than the single treatment of each material with 94.3%, 100% and 100%. Control efficacy of 0.3% COY+0.05% (95.3%) against the green peach aphid, Myzus persicae was higher than that of 0.3% COY+0.05% Neem (90.2%) and lasted for more than 21 days after one time treatment. At 35 days after treatment, the effect of 0.05% BT+0.05% Matrine and 0.05% BT+0.05% Matrine+0.05% Neem treatments against diamondback moth showed very high insecticidal activity with more than 90% of control value. Therefore, BT, Neem, and Matrine where are properly treated could be effective eco-friendly materials for controlling major insect pests in an organic Chinese cabbage field.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.411-418
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• 2013

The black pine bast scale, Matsucoccus thunbergianae is one of the most serious insect pest in Japanese black pine, Pinus thunbergii forest in Korea. Insecticidal activity of 10 folds hot water extracts from 7 herbal plants (Atractylodes lancea, Eugenia caryophyllata, Lonicera japonica, Melia azedarach, Quisqualis indica, Sophora flavescens and Taraxacum mongolicum) were tested against different stage of M. thunbergianae using spray method both in laboratory and field. Efficacies of herbal extracts were different depending on stage of M. thunbergianae. Q. indica sprayed with hand sprayer produced the highest corrected mortality of 95.7% on intermidiated nymph stage, however, A. lancea produced the highest corrected mortality (51.3%) on pupae of M. thunbergianae in laboratory. Q. indica and A. lancea were highly effective against female M. thunbergianae in laboratory, however, corrected mortality was lower than other stage (40.0%). Efficacy of Q. indica was similar to effective insecticide, fenitrothion 50% EC against M. thunbergianae in field trials. These results indicated that Q. indica could be an environmental friendly control agent of M. thunbergianae.

• Korean journal of applied entomology
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• v.18 no.2 s.39
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• pp.111-116
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• 1979

The experiments were carried out to evaluate the effectiveness of some insecticides in the control of the pine gall midges (Thecodiplosis japonensis Uchida et Inouye) when the low-volume of the insecticides were applied by the mist foliar sprayer. The insecticides, Salithion $(24\%\;Ec)$, Omethoate $(Folimat^{(R)}\;50\%\;Ec)$, Monocrotopos $(Azodrin^{(R)}24\%\;Ec)$, Acephate $(Ortran^{(R)}\;50\%\;Wp)$, Metalkamate $(Bux^{(R)}24\%\;Ec)$. BPMC $(Bassae^{(R)}50\%\;Ec)$ and MIPC $(Mipcin\;50\%\;Wp)$ were tested with 100, 200 and 400 times of water solution on the basis of single application at the six different intervals. Salithion was the most effective for the pressure of the gall formation by the pine gall midges and Omethoate, Monocrotophos and Metalkamate were relativey effective and others no effective. The most reliable concentration of the insecticides was 100 times of water solution, and the feasible timing of insecticide application on the basis of single application would be from May 9 to July 1 with Salithion, June 6 with Metalkamate and June 20 with Omethoate and Monocrotophos. The number of pine needles with the larval injured signs (no larvae in the needles) excluded the gall-formed needles were relatively higher in the treatments of Omethoate, Salithion and Monocrotophos than other insecticides. The treatments of Omethoate, Salithion and Monocrotophos caused the lower larval population in the gall than other insecticides.

• The Korean Journal of Pesticide Science
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• v.8 no.1
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• pp.71-78
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• 2004

A promising hyperparasite, Ampelomyces quisqualis 94013(AQ94013) was selected as a biological control agent to cucumber powdery mildew caused by Sphaerotheca fusca. Effect of agrochemicals on mycelium growth and spore germination of AQ94013 and effect of spread stickers on hyperparasitical activity of AQ94013 to powdery mildew pathogen were evaluated. Finally it was confirmed that mycelial growth and spore germination of AQ94013 on potato dextrose agar amended with two fungicides for controlling powdery mildew, triadimefon and pyrazophos; five fungicides for controlling downy mildew, dimethomorph, kasugamycin+copper oxychloride, dichlofluanid+copper oxychloride and tribasic copper sulfate; three fungicides for controlling gray mold, iprodione, vinclozolin and procymidone; and six insecticides immidacloprid, teflubenzuron, bifenthrin, ethofenprox, deltamethrin and phenthoate were slightly reduced. Addition of mineral oil in the spore suspension of AQ94013 enhanced 7.9% control value to cucumber powdery mildew.

• Research in Plant Disease
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• v.10 no.4
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• pp.209-216
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• 2004

The circular leaf spot of persimmon is occurred almost every place where persimmon is cultivated, especially the disease outbreak severely in southern part of Korea. The disease reveals unusually long incubation period after pathogen invade into leaf tissue and no practical control measure is available once the symptom has appeared. Most of the farmers just follow the suggested spray schedules calculated on the basis of weather condition of ordinary years. Therefore the damages due to circular leaf spot greatly differ year after year. In this article, we tried to describe and summarized the investigation on the circular leaf spot pathogen, Mycosphaerella nawae, related to disease outbreak such as overwintering of pathogen, inoculum formation and spread, incubation period after infection, and secondary inoculum. With the summary of these results, we suggest the disease cycle of circular leaf spot of persimmon. The pathogen overwinters in diseased leaves as mycelial form or pseudoperithecial premodium. The pseudoperitheria become matured in spring as the temperature raise and forms asci and ascospores. The maturation of pseudoperithecia are closely related to the temperatures during March and early April. The ascospores completely mature in early May and the ascospores released when the pseudoperithecia absorbed enough moisture after rainfall. The release of ascospores are diverse greatly with the variation of maturity of pseudoperithecia. Generally the spore start to release from middle of May to early of July. Duration of ascospore release is depend on the weather condition of particular year, especially amount and number of precipitation. The ascospores produced from pseudoperithecia is known to the only inoculum for circular leaf spot disease. But according to the results obtained from our investigations, the conidia formed on the lesions which incited by natural infection. This conidia are infectious to persimmon leaves and formed identical symptom as natural infection. The time of producing secondary inoculum of circular leaf spot of persimmon is considered too late to develop new disease. Generally the importance of secondary inoculum is low but the conidia produced in early September are competent to develop new disease and new infection also significantly affect to harvest of persimmon. The importance of circular leaf spot disease is recognized well to farmers. The approaches to control of the disease should be initiated on the basis of the knowledges of inoculum dynamics and ecology of disease development. The forecasting system for circular leaf spot is need to be developed.

• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.147-152
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• 2015

In order to develop the cooling load estimation method in the greenhouse, the cooling load calculation formula based on the heat balance method was constructed and verified by the actual cooling load measured in the fog cooling greenhouse. To examine the ventilation heat transfer in the cooling load calculation formula, we measured ventilation rates in the experimental greenhouse which a cooling system was not operated. The ventilation heat transfer by a heat balance method showed a relatively good agreement. Evaporation efficiencies of the two-fluid fogging system were a range of 0.3 to 0.94, average 0.67, and it showed that they increased as the ventilation rate increased. We measured thermal environments in a fog cooling greenhouse, and calculated cooling load by heat balance equation. Also we calculated evaporative cooling energy by measuring the sprayed amount in the fogging system. And by comparing those two results, we could verify that the calculated and the measured cooling load showed a relatively similar trend. When the cooling load was low, the measured value was slightly larger than calculated, when the cooling load was high, it has been found to be smaller than calculated. In designing the greenhouse cooling system, the capacity of cooling equipment is determined by the maximum cooling load. We have to consider the safety factor when installed capacity is estimated, so a cooling load calculation method presented in this study could be applied to the greenhouse environmental design.

• The Korean Journal of Pesticide Science
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• v.10 no.1
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• pp.36-42
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• 2006

For the effective control of pepper anthracnose, in vitro antifungal activities of 13 commercial fungicides were tested on spore germination, mycelial growth, and sporulation of Colletotrichum gloeosporioides, anthracnose fungus. Among them, captan, chlorothalonil, dithianon, fluazinam and folpet completely inhibited the spore germination of C. gloeosporioides at the concentration of 0.8 ${\mu}g/ml$. They were followed by mancozeb and propineb, showing more than 80% inhibition of spore germination at 20 ${\mu}g/ml$. The mycelial growth of C. gloeosporioides was strongly inhibited by fluazinam and nuarimol. Except for nuarimol, most of the fungicides represented more antifungal activity on the spore germination than the mycelial growth of C. gloeosporioides. Azoxystrobin and metominostrobin, Strobilurin fungicides, were only moderately active against the spore germination and the mycelial growth of C. gloeosporioides, but they were effective antisporulant against C. gloeosporioides. From these results, control of pepper anthracnose will have achieved by preventive spray of the commercial fungicides.

• The Korean Journal of Pesticide Science
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• v.13 no.3
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• pp.197-202
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• 2009

Based on the insecticidal efficacy by insecticide treatment methods, neurophysiological responses were compared with the larvae of diamondback moth (DBM) and beet armyworm (BAW) using pyrethroids working on nervous system. By body spray method, all pyrethroids were showed lower insecticidal activity below 50% on the larvae of DBM and BAW. By leaf dipping method, DBM larvae were showed the insecticidal activity as 100% at 50 ppm deltamethrin, 80.0% at fenvalervate and 63.3% at permethrin. However, BAW larvae were showed lower insecticidal activity as similar as control in all concentration. In order to examine electrophysiological response on nervous system on DBM and BAW larvae when treated three insecticides, we investigated the voltage and reaction degree. The voltage of DBM were responded as high as $10^{-7}M$ in deltamethrin, $10^{-5}M$ in fenvalerate and $10^{-3}M$ in permethrin. However, those of BAW were showed dull responses with small variation of voltage to all three insecticides.