• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.695-703
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• 2014

We experimented with the effect of oleic acid and its appropriate concentration to prevent powdery mildew eco-friendly in a cucumber greenhouse cultivation. 'Baekbongdadaki' (Nongwoo Bio. co. Korea) was treated in the plastic greenhouse at Sangmyung University. We treated four levels of concentration of oleic acid, which were 0, 2000, 4000, 6000, and 8000 ppm. There were investigated diseased severity, diseased leaf area, control value, and pesticide injury. The degree of control values by oleic acid treatments was investigated at 3 days after treatment. The recurrence of powdery mildew was checked for 55 days. The day and night temperature in the greenhouse were controlled to 23 and $15^{\circ}C$ respectively. The humidity inside the greenhouse was not controlled to prevent outbreak of the disease. From the experimental results, oleic acid was very efficient to control powdery mildew. 2000 ppm of oleic acid was shown to be the most control efficiency without any pesticide injury. The recommended method to treat it was to spray three times every 3 weeks.

• Korean journal of applied entomology
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• v.60 no.2
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• pp.229-234
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• 2021

This study investigated spray patterns and coverage generated by three types of commercial nozzles for spraying pesticides with Unmanned Aerial Vehicles (UAVs) using a multi-copter. Flufenoxuron+metaflumizone SC and bifenthrin EC were sprayed. The falling particles of the spraying agent were measured using WSP (Water and oil Sensitive Paper) and the coverage was determined. The results showed that the uniformity of falling particles was different according to the difference in wind strength, and there was no difference for different formulations. The injection amount for each nozzle was found to be different from the official information provided by the manufacturers. These results could be used to establish guidelines for the control of UAVs and pesticide registration testing.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.312-316
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• 2015

Anthracnose, caused by Colletotrichum spp. is the most important and devastating disease in sweet persimmon production in worldwide. There is no alternative control method or resistant cultivar is available. Therefore, chemical controls are widely accepted to control the disease. Three fungicides among 16 fungicides have been selected to apply in field condition. The selected three fungicides (metconazole, dithianon and propineb) showed lower EC50 and reliable control effect in both in vitro and in vivo. According to general guide line of anthracnose disease control method recommended 8 times spay of the fungicide. In this study, we performed 8, 4, and 2 times spay of the fungicides. For 8 times application, practice spray machine has been used and for 4 and 2 time application, a recently invented spray machine was input. The fungicides have been treated from middle of June to end of August in 2014 year. Control effect of among the selected fungicides showed similar result regardless of sort of the fungicide. However, frequency of spray result showed significantly different results, 8 and 4 times fungicide application showed low and similar disease occurrence, but 2 times application showed intermediated disease occurrence between 4 times treatment and untreated control. Taken together, result showed that 4 times application with effective fungicide, mechanically advanced tool can reduced the anthracnose disease damage in sweet persimmon production.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.434-438
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• 2014

The mixture of fluxapyroxad plus pyraclostrobin or the 9 time-spray schedule with various fungicides was evaluated for their efficacy in controlling pear scab in field trials. It showed sufficient condition to evaluate the efficacy of fungicides for the control of pear scab since disease incidence of the untreated control plot was 58.4% or 100% on leaves or fruits, respectively. Pear scab on leaves was occurred by 6.3% at treated plot with the mixture of fluxapyroxad plus pyraclostrobin, resulting in the 89.2% of control value. Incidence of the fruit disease was 16.7% at treated plot with the mixture of fluxapyroxad plus pyraclostrobin, showing 83.3% of control value. When the 9 time-spray schedule was tested, pear scab was occurred by 5% or 13.3% on leaves or fruits, respectively. Their control values were the 91.4% on leaves or 86.7% on fruits. Although the 9 time-spray schedule showed slightly lower disease incidence than the mixture of fluxapyroxad plus pyraclostrobin, but there is no statistically significant difference. These results suggest that the mixture of fluxapyroxad plus pyraclostrobin can control effectively the pear scab.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.284-288
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• 2010

A series of experiments was carried out for selecting insecticides and determining proper spraying time to control pea weevil (Bruchus pisorum Linnaeus) in Jeonnam area. In the field trial two times spray with diazinon, carbaryl, imidacloprid, spinosad, etofenprox, clorpyrifos-methyl showed good control effect and threetimes spray showed the better control effect. The second spray (spraying on 10th of May) took the major role of insecticide effectiveness expression for controlling pea weevil. Further trial for selecting insecticides among organophosphates to control pea weevil in lab was conducted and every organophosphate insecticide tested was very effective to pea weevil even at the concentration of one forth of its recommending concentration.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.282-287
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• 2012

This study was carried out to clarify the effects of the application of pesticide by different spray nozzle types on pesticide residues. The average droplet size and discharge rate were investigated when the manual compressed sprayer with two head disk type nozzle and the knapsack engine powered sprayer with two head fan shape nozzles were used. The fan type nozzles were classified into three types by the number of orifice in the nozzle. Three type nozzles tested were fan with one orifice, fan with two orifices and fan with three orifices. Fan (trade name : D-3) with 2.4 L/min. of the discharge rate and $76{\mu}m$ of the average droplet size while maintaining constant pressure $1.1{\pm}0.2$ MPa, and fan D-35 with 2.6 L/min. and $90{\mu}m$ while maintaining constant pressure $1.0{\pm}0.2$ MPa were appropriate. The orifice size of D-3 was 0.65 mm length ${\times}$ 0.45 mm width and the orifice size of D-35 was 0.62 mm length ${\times}$ 0.46 mm width. The residue levels of imidacloprid on perilla leaves among four applications by four different nozzles show significantly difference with 5% significance level. The residue levels $3.76{\sim}3.92mg\;kg^{-1}$ by fan or disk type is smaller than $4.52{\sim}4.92mg\;kg^{-1}$ by fan II or fan III. The residue levels of imidacloprid on perilla leaf were different depend on the spray nozzles type.

• Journal of Bio-Environment Control
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• v.31 no.1
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• pp.52-59
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• 2022

Pest control treatment was carried out using an unmanned automatic pesticide spraying system that can spray pesticides on crops while moving autonomously to control pests in vegetable greenhouse. As a result of examining the control effect on tomato and strawberry on thrips (Frankliniella occidentalis) and greenhouse whitefly (Trialeurodes vaporariorum) pests, 85.6% of yellow flower thrips were found in tomatoes and 87.5% in strawberries, and 81.7% (tomato) and 80.6% (strawberry) of greenhouse whitefly. In addition, the control effect according to the pesticide treatment method showed a control effect of 81.7% of the chemical spraying treatment by manpower and 83.9% of the automatic moving pesticide spraying treatment (F=22.1, p < 0.001). When comparing the control effect between the two treatment sections, there was no significance, but the automatic transfer spraying treatment showed a 2.2% higher effect. On the other hand, as a result of comparing the spraying time of the drug, the automatic unmanned control sprayer had a spraying time of 5 min/10a, which took about 25 min less than the conventional manpower spraying time of 25-30 min/10a. Based on these results, it was judged that the automatic transfer spraying method could be usefully used for efficient pest control in the facility greenhouse during the peak period of development.

• Food Engineering Progress
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• v.15 no.1
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• pp.28-33
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• 2011

UV-C and -B types of lamps, and $H_2O_2$ as a photocatalytic material were applied to optimize processing conditions for pesticides removal in Mandarine orange peel. Factors to affect the removal of pestrcides were arranged as a function of irradiation temperature, irradiation time, and $H_2O_2$ spray concentration. The optimum processing conditions for the chloropyrifos and the EPN removals in Mandarine orange peel were irradiation time of 60 min, irradiation temperature of $45^{\circ}C$ and $H_2O_2$ spray concentration of 1000 ppm. However, the optimum processing conditions for methidathion removal were 60 min of irradiation time, $40^{\circ}C$ of irradiation temperature and 1000 ppm of $H_2O_2$ spray concentration. The residual percentages of chloropyrifos, EPN and methidathion were 46, 49 and 28% after above irradiation processing, respectively.

• Korean journal of applied entomology
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• v.44 no.2
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• pp.115-123
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• 2005

Historical changes of population abundances of European red mite (ERM), Panonychus ulmi (Koch), and two-spotted spider mite (TSSM), Tetranychus urticae (Koch) (Acari: Tetranychidae), were described in selected apple orchards in the National Horticultural Research Institute (NHRI, Suwon, Korea), based on research reports of the NHRI from 1958 to 1998. ERM was an abundant species up to 1970, and TSSM became a dominant species after 1980. The change occurred around mid 1970. Three hypotheses were made to explain the change: TSSM competitively replaces ERM, ground cover weeds are a major influencing factor on movement of TSSM (TSSM movement into trees is accelerated by destroying weeds), and ERM and TSSM populations are regulated by natural enemy complexes when the orchard system is not disrupted. And long-term results of the interaction between two species were projected according to the combination of different orchard management strategies: pesticide sprays (non-selective toxic pesticide spray : heavy pesticide pressure (HPP), and selective soft pesticide spray = low pesticide pressure (LPP)) and weed control methods (grass planting, and clean culture system with herbicides). In the HPP and grass planting system, ERMs are abundant because ERM can avoid competition with TSSM as movement of TSSM to trees are restricted, and natural enemy complexes are destroyed by toxic pesticides. In the HPP and clean culture system, TSSMs are abundant because TSSM moves to trees from early season and competitively replaces ERM. In the LPP and grass planting system, ERMs are abundant because movement of TSSM to trees is reduced, but they do not build up a high population density since their densities are regulated by natural enemy complexes. In the LPP and clean culture system, TSSM moves to trees and competes with ERM, but the competition pressure is reduced because population densities of mites are regulated in a lower level by natural enemy complexes. So, ERM can occurs in late season. Thus, two species can coexist temporarily with more ERM in early season and more TSSM in late season. TSSM abundant phenomenon presented in this study can be partially explained as a result of long-term interaction between ERM and TSSM under the HPP and clean culture system.

• Korean journal of applied entomology
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• v.61 no.1
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• pp.255-266
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• 2022

This study was conducted to examine the effects of grass vegetation (W: manual weeding, NW: herbicide sprays) and pyrethroid spray (P: pyrethroid spray, NP: no pyrethroid spray) on the population dynamics of Panonychus citri and natural enemies in citrus orchards. Two essential hypothesis were made to test the population dynamics: 1) weed planting promotes natural enemies by offering habitat and alternative food sources, resulting in the reduction of P. citri populations, and 2) pyrethroid spray removes natural enemies by its non-selective toxicity, resulting in the increasement of P. citri populations. The observed natural enemy populations (mainly Phytoseiids and Agistemus sp.) were not different largely from the expected values in the hypothesis, which assumes more abundant natural enemies in weeds and no pyrethroid plots. Although some discrepancy was occurred in NW+NP and W+NP plots in 2011, the observed values were almost same with expected values in 2012. In overall, pesticide effect was strongly significant and pyrthroids removed largely natural enemies. Although habitat (weeds) effect showed a conflict result, natural enemy population increased in plots allowing weed growth, when considering the increased autumn population relatively compared to that of spring-summer population. The decreased abnormal P. citri populations in pyrethroid plots could be explained under the assumption of a strong repellent behavior of P. citri to the pyrethroids.