• Korean journal of applied entomology
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• v.44 no.3 s.140
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• pp.225-230
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• 2005

This study was conducted to investigate the developmental characteristics of cabbage armyworm, Mamestra brassicae L. (Lepidoptera: Noctuidae) by different temperatures and its seasonal occurrence in pepper field. Under four constant temperatures, 15, 20, 22 and $25^{\circ}C$, developmental periods from egg to adult were 88.3, 63.0, 52.3, and 42.8 days, respectively, with egg periods being 9.2, 6.2, 5.0 and 3.9 days, and larval periods being 40.5, 30.1, 23.3 and 21.2 days, respectively. Developmental threshold and thermal requirement in degree-days (DD) were $7.9^{\circ}C$ and 69.4 DD for egg, $4.8^{\circ}C$ and 434.8 DD for larva and $6.7^{\circ}C$ and 344.8 DD for pupa. Fecundity of female increased as temperature increased laying 1262.1 eggs at $15^{\circ}C$, 1663.8 eggs at $20^{\circ}C$ and 1763.2 eggs at $25^{\circ}C$. Mean numbers of eggs per egg-mass were 99.4, 114.7 and 167.9 under the three constant temperatures, respectively. In Daegwallyeong highland area, this noctuid occurred from mid June to late August and has two generations a year reaching peak two times, one at late June and the other at early August.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.411-421
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• 2005

This study was carried out to establish rational methodologies for the use of pesticide formulations to be sprayed after water-dilution. Hardness and electric conductivity of six major river water and ground water sampled from 52 sites in major rice-growing areas across the country ranged from 5 to 324 ppm(av. 90 ppm) and from 0.038 to 1.078 dS/m(av. 0.265 dS/m), respectively, which are acceptable for diluent water of pesticides. The pH changes in pesticide spray solutions with time after preparation mainly depended on the pH of the water used for pesticide dilution. The surface tensions of pesticide spray solutions reduced slightly with time after preparation, irrespective of kinds of pesticide formulations. Suspensibility of WPs became worse with an increase in the hardness and salt concentrations of diluent water, even though the degree was negligible. Emulsion stability of ECs became worse with an increase in hardness and salt concentrations of diluent water. Degradation rates of the active ingredients of pesticide spray solutions 3 days after preparation were less than 5%, regardless of mixing or non-mixing of two or more pesticides. Consequently, the spray solutions of most pesticides were usable until two to three days after preparation unless physical properties deteriorated. The tank-mixing order of EC and WP formulations did not make any differences in all the physical properties of pesticide spray solutions. However, the proper order for the tank-mixing of compatible pesticides was WP, WG, SC, EC, and SL, because the order is easy to prepare the pesticide spray solutions. The efficacy of pesticide spray solutions on the respective target pathogens and insect pests of rice plants three days after preparation was recorded over 95% of that of 0 day, which was almost the same as that of the solutions applied punctually after preparation.

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.210-215
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• 2007

This study aims to investigate if the properly use of pesticide in Ginseng farmland at Gangwon-do, Korea. Questionnaire included 36 questions such as control method for plant diseases, pests and weeds and pattern of pesticide use was answered by 271 Ginseng farmers lived in 4 cities and 8 counties at Gangwon-do. Ginseng farmers have noxious plant diseases, insects and weeds such as leaf spot, anthracnose, snail, stem-mining fly, horseweed and hairy crabgrass. To control of these, 35% of farmers relied on various type of pesticides and 31.5% of farmers used pesticides mingling with natural enemy, microorganism and organic materials. Farmers selected the pesticide based on the their own experiences or by recommendation of market dealers and neighbors, resulting in the use of inappropriate pesticides in the Ginseng farmland(78.8 % ). They followed standard dosage of the pesticide from Handbook of Pesticide Application(96.3%). They, however, used the same pesticides from 2 to 5 years(44.1 %). This consecutive use of pesticide could be induced resistance. This survey resulted that study for pesticide resistance and systematic educational program for proper use and selection of pesticide to Gingseng farmers should be conducted in farmland at Gangwon-do, Korea.

• Research in Plant Disease
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• v.29 no.4
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• pp.363-376
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• 2023

Alternaria black spots or blights in cruciferous crops have been devastating diseases worldwide and led to economic losses in broccoli, Chinese cabbage, kale, radish, rapeseed, etc. These diseases are caused by different Alternaria spp., including A. brassicae, A. brassicicola and A. raphani transmitted from infected seeds or insect vectors. Efforts to excavate disease resistance traits of cruciferous crops against Alternaria black spots or blights have been demonstrated. Genetic resource of disease resistance was investigated in the wild relatives of cruciferous crops, and different cultivars were screened under different inoculation conditions. Development of the disease-resistant lines against Alternaria black spots or blights was also tried via genetic transformation of the cruciferous crops using diverse plant defence-associated genes. Plant immunity activated by pre-treatment with chemicals, i. e. β-amino-n-butyric acid and melatonin, was suggested for reducing Alternaria black spots or blights in cruciferous crops. The disease resistance traits have also been evaluated in model plant Arabidopsis originating from different habitats. Various plant immunity-related mutants showing different disease responses from wild-type Arabidopsis provided valuable information for managing Alternaria black spots or blights in cruciferous crops. In particular, redox regulation and antioxidant responses altered in the Alternaria-infected mutants were discussed in this review.

• Korean Journal of Heritage: History & Science
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• v.54 no.2
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• pp.194-215
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• 2021

Termites are important decomposers in the ecosystem. They are also economically significant structural pests. In this study, we reviewed the developments of termite control and recent research on termite management to provide information on the prevention and control of termites. In Korea, most of the damage to wooden historical buildings is caused by subterranean termites. Reticulitermes speratus kyushuensis is the main species, which is widely found throughout the country. In the early 1900s, inorganic insecticides, such as arsenic dust, were used for termite control. After the synthesis of chlorinated hydrocarbon pesticide in the 1940s, it was widely utilized and demonstrated high termite control efficacy. However, chlorinated hydrocarbon insecticides were later banned, disappearing from markets after reports emerged concerning environmental contamination and toxicity to humans. Therefore, the termite control industry sought a new termiticide; hence many pesticides were utilized for termite control. Organophosphate (1960s), carbamate (1970s), pyrethroid, and insect growth inhibitor (1980s) were newly synthesized and adopted. In the 1990s, the first commercial baits using chitin synthesis inhibitors (CSI) were developed, providing a means to eliminate an entire colony of subterranean termites around a structure. Many studies have been carried out on soil termiticides (liquid termiticides) and CSI baits to increase their efficacy, and different baits such as aboveground bait stations, fluid bait, and high-durability bait were also developed in the 2000s. In addition, the paradigm of termite control has shifted from localized treatments using soil termiticides to area-wide pest management using CSI baits to create termite-free zones and protect buildings over time. Termite infestations in wooden historical buildings in Korea have been reported since 1980, and considerable attention was drawn in the 1990s when several UNESCO world heritages such as the Jongmyo Shrine and the Janggyeong Panjeon Depositories of Haeinsa Temple were infested by subterranean termites. Since then, a survey of termite infestation in wooden architectural heritage has been conducted, and the National Research Institute of Cultural Heritage and Heritage Care Program regularly monitors those properties. Finally, we suggest termite management using primarily CSI baits, selective application of various soil treatments applied to the object, foundation soil treatment, research and development of durable termite baits, application of area-wide programs for wooden-building complexes, application of integrated termite management (ITM), and regular education for owners and managers to prevent and reduce termite damage.

• Korean journal of applied entomology
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• v.48 no.2
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• pp.237-243
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• 2009

This study was conducted to develop economic injury level (ElL) and economic threshold (ET) of Cabbage armyworm, Mamestra brassicae L. on cabbage (Brassica oleracea L. var). The changes of cabbage biomass and M. brassicae density were investigated after introduction of larval M. brassicae (2nd instar) at different densities: 0, 1, 2, 4, 8, and 16 larvae per plant at 40 d after planting for an open field experiment, and 0, 2, 5, 8 and 12 larvae per plant at 25 d after planting for a glass house experiment. In the field experiment, the yield loss of cabbage was not significantly different among treated-plots at 30 d after the larval introduction, showing an over-compensatory response of cabbage plants to M. brassicae attack. In the glasshouse experiment, however, the biomass of cabbage at 15 d after the larval introduction significantly decreased with increasing the initial introduced number of M. brassicae, resulting in 38.3, 36.7, 21.7, 23.3 and 16.7g in above treated-plots, respectively. The relationship between cumulative insect days (CID) and yield loss (%) of cabbage was well described by a nonlinear logistic equation. Using the estimated equation, ElL of M. brassicae on cabbage was estimated at 44 CID per plant based on the yield loss 14%, which take into account of an empirical gain threshold 5% and marketable rate 91% of cabbage. Also, ET was calculated at 80% of the EIL: 35 CID per plant. Until a more elaborate EIL-model is developed, the present result may be useful for M. brassicae management at early growth stage of cabbage.

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.284-292
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• 2012

To date, chemical control remains the most common way to reduce beet armyworm (Spodoptera exigua) populations. However, this insect has become more tolerant or resistant to many chemical insecticides and the insect larvae usually hide inside hollow, tube-like leaves of host plant so they were difficult to kill by spraying insecticides. The use of viral and bacterial insecticide to solve these problems has not been successful because of their novel feeding habit. To overcome these problems, in this study, the biological characteristics and virulence of an entomopathogenic fungus isolated from the cadaver of larvae beet armyworm were investigated. Isolated entomopathogenic fungus was identified as Nomeraea rileyi (Farlow) Samson by morphological examinations and genetic identification using sequences of the ITS, ${\beta}$-tubulin gene and EF1-${\alpha}$ regions. This fungus was named as N. rileyi SDSe. Virulence tests against 3rd larvae of beet armyworm were conducted with various conidial suspensions from $1{\times}10^4$ to $10^8$ conidia/ml of N. rileyi SDSe in laboratory conditions. Mortality rate of beet armyworm showed from 20 to 54% and the virulence increased with increasing conidial concentrations. Although N. rileyi SDSe showed low mortality rate against beet armyworm, it is expected that N. rileyi SDSe will be used effectively in the integrated pest management programs against the beet armyworm.

• Food Science and Preservation
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• v.15 no.5
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• pp.635-641
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• 2008

This study was conducted to investigate the optimal sub-zero temperature for storage of two garlic cultivars, the northern ecotype 'Jaerae' and the southern ecotype 'Daeseo'. These cultivars of garlic bulbs were stored at different temperature (room temperature, $0^{\circ}C$, and $-4^{\circ}C$) conditions after predrying. Southern ecotype garlic showed higher weight loss than northern ecotype garlic. Northern ecotype garlic at $-4^{\circ}C$ exhibited less than 5% of weight loss during 10 month storage. Sprouting rate was higher in southern than in northern ecotype at room temperature storage. The value of injury by disease and insect was similar between southern ecotype and northern ecotype for 5 month storage, and then northern ecotype showed higher value of injury by disease and insect than southern ecotype. Hunter 'b' value of northern ecotype garlic was the lowest at $-4^{\circ}C$ storage. Northern ecotype garlic showed no cold injury at freezing point temperature storage. However, southern ecotype garlic had $0{\sim}5.3%$ cold injury occurrence at $-4^{\circ}C$ storage. Respiration and ethylene production exhibited the highest at room temperature storage, those had the slight increase at $0^{\circ}C$ and $-4^{\circ}C$ storages. Northern ecotype showed higher enzymatic pyruvic acid and fructan contents than those of southern ecotype. Enzymatic pyruvic acid content increased and fructan contents decreased during storage time.

• Journal of Wetlands Research
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• v.25 no.3
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• pp.184-195
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• 2023

To develop an effective management plan for Ambrosia trifida L., an invasive alien plant in Korea, we assessed the potential of Ophraella communa LeSage as a biological control agent. This involved investigating the host specificity of the herbivore Ophraella communa LeSage, its annual travel distance, and the impact of this insect on the fitness of Ambrosia trifida L. We confirmed the host plant preference of Ophraella communa LeSage. The travel distance of this insect was determined by monitoring its appearance in selected Ambrosia trifida L. communities without these insects at distances of 10, 20, 30, and 100 meters, based on the locations where the presence of Ophraella communa LeSage was observed. The growth, reproductive, and physiological responses of Ambrosia trifida L. were measured according to feeding by Ophraella communa LeSage. As a result, Ophraella communa LeSage fed on only three taxa and moved short distances within a radius of 30 m per year from the host. The feeding behavior of the herbivore had a negative impact on the growth, reproductive, and physiological responses of Ambrosia trifida L. And the plant's growth and reproduction improved with increasing distance from the herbivore. Furthermore, the introduction of herbivores was able to control over 90% of Ambrosia trifida L. when the coverage of the Ambrosia trifida L. group was below 50%. However, the effectiveness of the removal decreased when the coverage exceeded 90%. These results are likely to be utilized by Ophraella communa LeSage as an ecological control agent. It is advantageous to introduce them in spring (May) when the coverage is low to maximize the effectiveness of control.

• Korean Journal of Weed Science
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• v.31 no.3
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• pp.279-288
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• 2011

To suggest the weed management technique for environment friendly rice cultivation, we investigated occurrence patterns of weeds, the actual condition of weed management, and rice yield at the environment friendly agricultural complex located in Honam and Chungnam regions. The practical performance of weed management was relatively satisfactory in decreasing order of agricultural technique with golden-apple-snail (GAS) > agricultural technique with duck (Duck) > agricultural technique with rice bran (RB) > agricultural technique with soft-shelled turtle (ST). In the rice fields employed by agricultural technique with GAS, the dominant weeds were Echinochloa crus-galli, Ludwigia prostrata, Monochoria vaginalis, Sagittaria trifolia, and Aneilema keisak. However, E. crus-galli, M. vaginalis, L. prostrata, Aeschynomene indica and Bidens frondosa were found as dominant weeds at the fields using the Duck and E. crus-galli, M. vaginalis, L. prostrata, Polyganum hydropiper and Eleocharis kuroguwai at the fields using RB. In comparison of rice yield ($5.2\;MT\;ha^{-1}$) obtained from the conventional cultivation using herbicides, about 93% was reached by Duck, about 91% by GAS, about 92% by RB, and about 78% by ST. When rice qualities obtained from environment friendly rice cultivation were compared with those from the conventional cultivation, the producing rates of perfect kernel, immature kernel, immature opaque kernel, cracked rice, and damaged kernel were lower in the former cultivation, whereas contents of protein, amylose, and fatty acid were similar in the two cultivation methods. The problems found in the environment friendly agriculture were poor plowing and harrowing, carless irrigation management, and geological poor condition as cultivation area with cold water. These have caused severe infestation of weeds, frequent incident of disease and insect pest, and rice lodging. This resulted in reduction of rice yield as high as about 32 to 79% as compared with the conventional cultivation using herbicides.