• Korean journal of applied entomology
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• v.62 no.4
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• pp.299-305
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• 2023

Bemisia tabaci is one of polyphagous insect pests that transmits Tomato Yellow Leaf Curl Virus (TYLCV) and Cassava Brown Streak Disease (CBSD). Insecticides are primarily applied to control B. tabaci, but it has limits due to the development of resistance. As a result, a fixed precision sampling plan was developed for its integrated pest management (IPM). The tomato plants were divided into top (more than 130cm from the ground), middle (70 cm to 100 cm above the ground), and bottom (50 cm or less above the ground) strata, before visual sampling of the larvae of B. tabaci. The spatial distribution analysis was conducted using Taylor's power law coefficients with pooled data of top, middle, bottom strata. Fixed precision sampling plan and control decision-making were developed with precision levels and action threshold recommended from published scientific papers. To assess the validation of the developed sampling plans, independent data not used in the analysis were evaluated using the Resampling Validation for Sampling Plan (RVSP) program.

• Smart Media Journal
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• v.11 no.5
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• pp.48-55
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• 2022

Tomato crops are easy to expose to disease and spread in a short period of time, so late measures against disease are directly related to production and sales, which can cause damage. Therefore, there is a need for a service that enables early prevention by simply and accurately diagnosing tomato diseases in the field. In this paper, we construct a system that applies a deep learning-based model in which ImageNet transition is learned in advance to classify and serve nine classes of tomatoes for disease and normal cases. We use the input of MobileNet, ResNet, with a deep learning-based CNN structure that builds a lighter neural network using a composite product for the image set of leaves classifying tomato disease and normal from the Plant Village dataset. Through the learning of two proposed models, it is possible to provide fast and convenient services using MobileNet with high accuracy and learning speed.

• Korean journal of applied entomology
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• v.59 no.1
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• pp.55-64
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• 2020

Smart greenhouses are primarily used for growing fruits and vegetables, such as sweet peppers, tomatoes, strawberries. Although the number of smart greenhouses has been increasing exponentially, no studies have been performed to evaluate the state of smart greenhouses in Korea. Therefore, this study was conducted to determine current state of smart greenhouses with regard to greenhouse specifications, crop growing methods, pests, and user satisfaction in Korea. Contact information for smart greenhouses was provided by the officials of local agricultural research and extension services. This survey was conducted by visiting each greenhouse. Results showed that approximately 50% of surveyed smart greenhouses were between 3,300 ㎡ and 6,600 ㎡. The most frequently chosen method for pest control was chemical pesticides (97.1%). Powdery mildew and gray mold comprised 54.4% and 33.8% of the crop diseases, respectively. All tomato greenhouse farmers considered whiteflies the most problematic pest. In contrast, 76.5% and 70.6% of sweet pepper farmers believed thrips and aphids posed significant threats, respectively. The mean satisfaction score was 7.5 out of 10 points, with 10 being "extremely satisfied". These results will aid in decision making with respect to the management of current smart greenhouses and the design of future smart farms in Korea.

• Korean Journal of Organic Agriculture
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• v.21 no.1
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• pp.95-104
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• 2013

This research was performed to test the effects of oleic acid for the management of greenhouse whiteflies and tobacco whiteflies. Tobacco whiteflies, especially, are the vectors of tomato yellow leaf curl virus on tomato plants. Whiteflies are not only the vectors of various viruses but also the major insect pests that cause direct damages through sucking and induce sooty mold with their sweet dew on tomato plants. There are many eco-friendly management measures including the use of yellow sticky trap and natural enemies such as Eretmocerus eremicus and Amblyseius swirskii. However, these management measures have difficulties to implement in the greenhouse. Therefore, in this research, oleic acid was tested for its effect on the management of whiteflies at various concentrations of 1,000ppm, 2,000ppm, or 4,000ppm. As a result, treatments of 1,000ppm, 2,000ppm and 4,000ppm oleic acid showed the control value of 70%, 76% and 84%, respectively. In another test, treatments of 2,000ppm oleic acid, and control treatment of 1,5000ppm neem oil and 50ppm dinotefuran showed the control value of 82%, 75%, and 75%, respectively. Cost for one application of oleic acid and neem oil for 10a area would be 3,180 Won and 20,150 Won, respectively. As a result, it was assumed that the use of oleic acid would be a appropriate management measure.

• Korean Journal of Organic Agriculture
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• v.10 no.4
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• pp.1-7
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• 2002

CODEX의 유기농업기준에 대하여 기본적으로는 공감하고 있으나, 아시아적 기후의 특성과 농가당 소유면적이 유럽이나 미주$\cdot$오세아니아 지역에 비하여 상대적으로 너무 협소한 점을 감안하여 아시아의 유기벼 재배농가들에게 과중한 부담을 주지 않을 수 있는 선에서의 유연성을 부여해야 할 것이다. 윤작이나 휴경의 경우, 지역에 따라 벼-딸기 등의 과채류-벼-토마토 등 과채류-벼 행태나, 병-보리 또는 호밀 등의 사료 또는 녹비작물-벼-자운영 등의 사료 또는 녹비작물-벼 행태의 윤작 또는 녹비작물 재배형태의 윤작 또한 유기재배로 인정해야 할 것이다. 완충지배 역시, 일정거리 보다는 경계선상에 주작물보다 상당히 키가 큰 다른 식용이나 녹비용 작물을 재배하면서 이웃 관행농장으로부터의 영농화학물질의 비산을 막아줄 수 있는 조처만으로도 유기재배 인증획득이 가능토록 해야 할 것이다. 제체작업 또한 오리를 이용할 경우, 기본적인 제초효과는 물론 해충포식이 이루어지며, 배설물에 의한 자연적인 시비가 원활히 이루어지게 볏대를 튼튼하게 자극시켜주며, 고랑사이의 공기유통 촉진과 흙탕물에 의한 잡초 발아억제 효과 등 다양한 부대효과를 올리 수 있게 된다. 왕우렁이 제초법 또한 논의 건조와 백로 등 조류의 접근만 차단해 주면 완벽한 제초가 이루어지고 있으며, 불시 경운에 의한 제초법도 유기농업 실천에 크게 기여할 수 있는 최선의 방안으로 활용되고 있는 중이다.

• The Korean Journal of Pesticide Science
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• v.8 no.4
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• pp.338-346
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• 2004

The methanol extract of Chloranthus japonicus roots effectively controlled the development of rice blast(Magnaporthe grisea), rice sheath blight(Corticium sasaki), tomato pay mold(Btrytis cinerea), tomato late blight(Phytophthora infestans), and wheat leaf rust(Puccinia recondita). From the methanol extract of C. japonicus roots, three antifungal substances were isolated. Their chemical structures were determined to be shizukanols B, C, and D mainly by mass and NMR spectral data. Among the three substances, shizukanol C showed the strongest inhibitory activity against mycelial growth of the plant pathogenic fungi tested; it completely inhibited mycelial growth of M. grisea. Colletotrichum gloeosporioides, and C. acutatum at concentrations of more than $12.5{\mu}g$/ and P. infestans at concentrations of more than $3.13{\mu}g/m\ell$. They also controlled effectively the development of rice blast and wheat leaf rust. On the other hand, they caused phytotoxic symptoms on barley leaves and inhibited the growth of duckweed (Lemna paucicostata) with $EC_{50}$ values of $30.0{\mu}g/m\ell$ for shizukanol B, $49.9{\mu}g/m\ell$ for shizukanol C, and $154{\mu}g/m\ell$ for shizukanol D. In addition, shizukanol C showed an insecticidal activity against brown planthopper (Nilaparavata lugens), peen peach aphid (Myzus persicae), diamond-back moth (Plutella xylostella), and tobacco cutworm (Spodoptera litura) of the 5 arthropod pests tested with mortality values of more than 60% at a concentration of $1,000{\mu}g/m\ell$.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.7-14
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• 2000

Methanol extracts from 21 grains were tested for fungicidal activities against six phytopathogenic fungi and for insecticidal activities toward five insect pests in a greenhouse. The efficacy varied with both the plant pathogen/insect pest and grain species used. Potent fungicidal activity at 5 mg/pot, were produced from extracts of Elymus sibiricus and Hordeum vulgare var. nudum against Pyricularia grisea and Erysiphe graminis and these of Sesamum indicum (W) and Triticum aestivum against Puccinia recondita and Erysiphe graminis. At 2,500 ppm, potent insecticidal activities were exhibited from the extracts of Fagopyrum esculentum against Myzus persicae and Ischaemum crassipes, and these of Oryzo sativa var. glutinosa, Panicum miliaceum, Setaria italica, Sorghum bicolor, and T. aestivum against Tetranychus urticae. All grain extracts revealed weak or no fungicidal and insecticidal effect against Phytophthora infestans, Plutella xylostella and Spodoptera litura. As a naturally occurring fungicide and insecticide, grain-derived materials described could be useful as new fungicidal and insecticidal products against phytopathogenic fungi and insect pests.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.375-380
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• 2014

The sweetpotato whitefly (SPW), Bemisia tabaci Gennadius, is a major pest in tomato greenhouses on Jeju Island because they transmit viral diseases. To develop practical sampling methods for adult SPWs, yellow-color sticky traps were used in commercial tomato greenhouses throughout the western part of Jeju Island in 2011 and 2012. On the basis of the size and growing conditions in the tomato greenhouses, 20 to 30 traps were installed in each greenhouse for developing a sampling plan. Adult SPWs were more attracted to horizontal traps placed 60 cm above the ground than to vertical trap placed 10 cm above the plant canopy. The spatial patterns of the adult SPWs were evaluated using Taylor's power law (TPL) and Iwao's patchiness regression (IPR). The results showed that adult SPWs were aggregated in each surveyed greenhouse. In this study, TPL showed better performance because of the coefficient of determination ($r^2$). On the basis of the fixed-precision level sampling plan using TPL parameters, more traps were required for higher precision in lower SPW densities per trap. A sequential sampling stop line was constructed using TPL parameters. If the treatment threshold was greater than 10 maximum adult SPWs on a trap, the required traps numbered 15 at a fixed-precision level of 0.25. In estimating the mean density per trap, the proportion of traps with two or more adult SPWs was more efficient than whole counting: ${\ln}(m)=1.19+0.90{\ln}(-{\ln}(1-p_T))$. The results of this study could be used to prevent the dissemination of SPW as a viral disease vector by using accurate control decision in SPW management programs.

• Korean journal of applied entomology
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• v.46 no.1 s.145
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• pp.63-69
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• 2007

This study was conducted to examine the problems that would arise in our cropping systems when introducing Gain Threshold (GT) which is an important element in determining Economic Injury Level (EIL). Cain Threshold (GT) can be defined as the amount of damage (=yield loss) to justify management, and calculated by dividing the management costs by the market crop price. GTs for some pests in rice, soybean, and greenhouse vegetable crops cultivation were estimated and also compared with those in foreign countries. GTs and percentage of yield loss equivalent to them were estimated to be 4.6-6.1kg/10a/season and 1.0-1.3% for brown planthopper, white-backed planthopper, rice water weevil, and sheath blight, whereas for rice blast in rice cultivation were 12.7kg/10a/season and 2.7%. In soybean cultivation, the values for bean bug were 6.2 kg/10a/season and 3.6%. GTs and percentage of yield loss estimated for melon thrips, whitefly, and downy mildew in cucumber cultivation were 10.0-12.6kg/10a/week, 1.4-1.7%, and the values for two spotted mite and gray mildew in strawberry cultivation were 3.1-3.5kg/10a/week, 1.3-1.5%, and the values for American leaf minor, whitefly, and gray mold in tomato were 8.4-9.7kg/10a/week, 1.7-1.9%. Overall GTs in our cropping systems were so low compared to those in foreign countries, which meant that the low GTs might yield the low EILs. Therefore, we could suggest that prior to direct introduction of GTs calculated from current cultivation systems in developing EILs it is necessary to seriously consider reasonable values of GTs or the yield loss equivalents to them.