• The Bimonthly Magazine for Agrochemicals and Plant Protection
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• v.13 no.1 s.106
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• pp.106-111
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• 1992

• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.402-410
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• 2015

The purpose of this study was to estimate the chitinolytic and antifungal activity of Actinomycetes sp.isolated from waste mushroom media. In five kinds of waste mushroom media, Sinyeong mushroom and Yangsongi were the order of the population density of actinomycetes. Totally 91 chitinolytic isolates of Actinomycetes sp. were obtained from waste mushroom media. The isolates were categorized into 3 groups based on chitinolytic activity and antagonisms against Phytophthora capsici, Rhizoctonia solani, Sclerotinia sclerotiorum, Collectotrichum gloeosporioides, and Cladosporium cucumerinum in vitro. CA-23 was selected as a representative isolate of a group showing strong chitinolytic and antagonistic activities to all of the plant pathogens, while AA-65 was selected as a representative isolate showing no chitinolytic activities but strong antagonistic activities to the pathogens. CA-23 and AA-65 were highly effective on control of Phytophthora blight of hot-pepper, powdery mildew and scab of cucumber in a greenhouse tests. Among the isolates tested, CA-23 showed highest control efficacy, while AA-65 not only effectively controlled the diseases but also consistently increased plant growth and yield. Although the isolates are similarly affected on suppression of plant pathogens, the isolates could be differ from each other in modes of action. Further studies on mechanisms and practical applications are being progressed.

• Korean journal of applied entomology
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• v.50 no.3
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• pp.171-178
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• 2011

Bacillus thuringiensis (Bt) is a bacterial biopesticide against insect pests, mainly lepidopterans. Spodoptera exigua and Plutella xylostella exhibit significant decreases in Bt susceptibility in late larval instars. To enhance Bt pathogenicity, we used a mixture treatment of Bt and other bacterial metabolites which possessed significant immunosuppressive activities. Mixtures of Bt with culture broths of Xenorhabdus nematophila (Xn) or Photorhabdus temperata ssp. temperata (Ptt) significantly enhanced the Bt pathogenicity against late larval instars. Different ratios of Bt to bacterial culture broth had significant pathogenicities against last instar P. xylostella and S. exigua. Five compounds identified from the bacterial culture broth also enhanced Bt pathogenicity. After determining the optimal ratios, the mixture was applied to cabbage infested by late instar P. xylostella or S. exigua in greenhouse conditions. A mixture of Bt and Xn culture broth killed 100% of both insect pests when it was sprayed twice, while Bt alone killed less than 80% or 60% of P. xylostella and S. exigua, respectively. Other Bt mixtures, including Ptt culture broth or bacterial metabolites, also significantly increased pathogenicity in the semi-field assays. These results demonstrated that the Bt mixtures collectively names "Bt-Plus" can be developed into potent biopesticides to increase the efficacy of Bt.

• The Korean Journal of Ecology
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• v.22 no.5
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• pp.255-263
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• 1999

Entomopathogenic nematodes were isolated through the investigation of soil samples from various biotopes in south Korea, the efficiency of isolation for highly pathogenic nematodes to silkworms (Bombyx mori) was as high as 28 %. Twenty-eight strains of nematodes, selected among 100 samples by silkworms were confirmed the pathogenicity, multiplicity, and tolerance against various condition of preservation. Pathogenicity of the nematode isolates to agricultural and environmental pests such as Calliphora vomitoria, Pseufaletia separata, Palomena angulosa, and Melolontha incana were high. Mortality was varied from 20 to 100% by the pest insects and nematode strains. The high detectablity of entomopathogenic nematodes resulted from the methods of collection for soil samples within 10 cm depth after eliminating dried soil surface and the use of silkworm trap. High population of entomopathogenic nematodes represented the strong activity and broad action radius in the environment. Most of the nematode isolates were successfully cultured on the silkworm host as well as on artificial media, and proved their potential for the use of biological control agent.

• The Korean Journal of Pesticide Science
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• v.7 no.3
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• pp.228-237
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• 2003

Temporary control schedules were tested at sweet persimmon orchards to development new control programs to meet the quarantine repuirements of America in 2001 and 2002. The 'MRL-type control orchards' were sprayed with chemicals which were possibly adaptable to the pome trees in America. A control schedule consisted of those chemicals registered for persimmon in Korea was incorporated in the 'domestic-type control orchards'. The efficacy of these two control type against insect pests was compared with that of a conventional control schedule. In 2001, MRL orchard and domestic orchard were sprayed 7 and 6 times, and two conventional orchards were 6 and 9 times, respectively. In 2002, acaricide was added once to the MRL orchards at late September to reduce the density of mites on harvested fruits. However no insecticide to plant bug control could be applied to the MRL orchards, because no insecticide against bugs was registered for pome trees in America. This resulted in 7 times of applications in MRL and domestic orchards. The conventional orchard was sprayed 9 times. Only the occurrence of the peach pyralid moth, Dichocrocis puntiferalis (PPM) out of 4 quarantine inset species was observed. The PPM was observed during growing season in MRL, domestic, and conventional orchards. However no fruits damaged by PPM larvae were observed after mid October and after harvest. In 2002 only 1 fruit out of 1,350 fruits inspected in June was damaged by the larvae of PPM at MRL orchards. A fungus-feeding mites and collembolan were under calyx of vested fruits. In 2001 they were found on 45.3% of harvested fruits at MRL orchard. However the percentage of fruits with mites in 2002 was greatly reduced to 3.5% at MRL orchard, presumably because of a added application of acaricide at late September. However percentage of fruits damage by hemipteran bugs at harvesting time was quite high 11.3 % at MRL orchards, because no application of insecticide against plant bugs.

• Korean journal of applied entomology
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• v.56 no.4
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• pp.345-350
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• 2017

Sunflower, selected as a trap plant that can be controlled by attracting Ricania spp. adults via attraction has the highest attractiveness during the preoviposition period. Considering the ecological characteristics of Ricania spp., adults are distinguished by the preoviposition and oviposition periods and the attractiveness of sunflower to Ricania spp. adults was 91.4~95.2% higher than that of blueberry during the preoviposition period. On August 20, when Ricania spp. adults entered the oviposition season, sunflower attractiveness was low at 9.8~11.6% owing to preference for tree species. Based on the result of the selection of systemic chemicals that could be used concomitantly with sunflower, all chemicals, except etofenprox, showed a high controlling effect of over 90%, and among them, dinotefuran showed the highest insecticidal rate of 95.8%. The systemic chemicals acetamiprid, dinotefuran, thiamethoxam, and imidacloprid persisted for 13 days (survey period). Therefore, the concomitant use of sunflower and systemic chemicals can reduce the density of Ricania spp. entering farmlands and their populations in surrounding habitats, which are expected to help in stabilizing the ecosystem.

• Research in Plant Disease
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• v.25 no.4
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• pp.173-178
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• 2019

From our field investigation from 2017 to 2018, five diseases and four insect pests have been identified as the primary biotic stressors of fruit-producing mulberry, which include popcorn disease and mulberry sucker, respectively. In this study, we examined the relative control effects of selected agro-chemicals against the popcorn disease and mulberry sucker. Our systemic treatment methods to simultaneously control the popcorn disease and the mulberry sucker indicated that an integrated control method showed a superior result with the control efficacy of 89.3%, while a conventional control method resulted in 66.7%. As a result, we concluded that it is much efficient to control both disease and insect pest in mid-April while sequentially applying chemicals only for the popcorn disease from February. By considering the ecological aspects of the popcorn disease and mulberry sucker, this systemic treatment will be able to reduce the labor of growers required for the control.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.255-265
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• 1996

토양에 존재하는 진균인 Gliocladium virens는 식물병을 감소 또는 방제할 수 있는 생물학적인 특성에 의하여 G. virens는 지난 수십년간 실용가능성이 큰 생물학적 방제균(또는 길항균)으로 집중적으로 연구되었다. 이 균이 식물병의 발생을 감소시키는 생물적 방제효과는 항생작용, 중복기생, 근권에서의 생존과 집단번식, 뿌리표면에서의 정착 등에 의한 것으로 분류되고 있다. 특히, 항생물질인 gliotoxin, gliovirin, viridin 등은 Rhizoctonia solani 및/또는 Pythium spp. 등에 항생효과가 뚜렷하고, 식물병의 발생과 직접적인 상관관계를 나타내고 있어 G. virens의 식물병의 방제에 관련된 중요한 작용기작으로 제시되어 있다. 또한, 근권에서 이균의 생존과 집단증식 및 뿌리표면에서의 정착은 식물병의 방제와 상관관계를 나타낼 수 있는 중요한 작용기작으로 제시되고 있다. 그러나 이균이 R. solani 등에 기생하는 현상은 식물병의 생물적 방제의 직접적인 연관관계를 나타내고 있지 않다. G. virens을 이용의 생물적 방제효과를 증진시키기 위한 방법으로 다음과 같은 두 가지 방법을 들 수 있다. 첫째, 길항효과가 높은 G. virens 균주를 선발하기 위하여 여러 종류의 토양에서 길항력이 높은 G. virens의 선발이 지난 수십년간 진행되고 있다. 또한, 특정 길항효과를 발현하는 유전자를 G. virens의 염색체에 도입하고 이를 발현시킴으로써 생물적 방제효과를 증진시키는 것으로 이러한 방법은 1980년 후반부터 진행되고 있다. 둘째, G. virens의 길항효과가 최대의 효율로 발현될 수 있도록 최적의 미세환경을 갖추고 있으며 농민이 편리하게 사용할 수 있는 G. virens의 운송매체의 개발이 중요하다. 운송매체의 개발에 의한 'Glioguard'는 G. virens의 포자를 alginate 입자에 제형화한 것으로서 미국에서 시판되고 있다. Aldicarb, metalaxyl, atrazine 등의 농약을 분해할 수 있는 능력은 G. virens의 다른 생물적 특성중의 하나이다. 특히, parathion을 분해할 수 있는 Flavobacterium sp.의 유전자(opd)가 G. virens의 염색체에 도입되여 발현될 수 있는 방법이 제시되었으며, 이는 G. virens을 이용한 토양에서의 특정한 농약의 분해효율을 증진시킬수 있는 가능성을 제시한 것이다. 그러나, G. virens를 이용한 농약의 생물적 분해에 관한 연구는 기초단계로 평가되고 있으며, 포장에서 이를 실용화하기 위해서는 향후 지속적인 연구가 필요하다.

• Korean Journal of Organic Agriculture
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• v.17 no.4
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• pp.557-566
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• 2009

This study was conducted to develop an organic control of powdery mildews of cucumber by using mayonnaise in green house. The treatment of 0.1~2% mayonnaise resulted in 8.3%~99.2% control efficiencies against powdery mildew of cucumber. 0.5% mayonnaise treatment resulted control values over 97% in disease. It did not adversely affected the photosynthesis of foliages. Although one application of mayonnaise to the foliage was not practically effective enough, two or three application of mayonnaise to the foliage at the 0.5% concentration resulted in excellent control against powdery mildews. This treatment could provide protection for 10~14 days after application. Among the type of mayonnaise, general mayonnaise revealed 97.5% control value, but mayonnaise containing low oil content revealed 39.3%~97.5% control values on powdery mildews at the 0.5% concentration. Therefore, oil content in mayonnaise played a essential material to control powdery mildew. Results indicated that mayonnaise could be used as organic control of powdery mildews of cucumber. This control might be environmentfriendly as well as cost-effective.

• The Korean Journal of Pesticide Science
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• v.20 no.3
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• pp.181-188
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• 2016

BtPlus is a group of biopesticides that are made of Bacillus thuringiensis and immunosuppressant. A new BtPlus that exhibits high insecticidal activity against mosquito larvae has been investigated in control efficacy in field conditions and its environmental safety against aquatic system. This study assessed the control efficacy of BtPlus against mosquito larvae with two different application methods. In aerial spraying application (100 mL per $3.3m^2$), BtPlus was effective at 50% or above formulation concentrations to control mosquito larvae. For a direct application to aqueous mosquito habitat, a semi-field mimicking paddy rice field was constructed. In this condition, BtPlus showed 80% and 100% control efficacies at 0.1% and 0.2% concentrations, respectively. BtPlus also showed 40% mortality against adults at 0.1% concentration in 10% sugar bait. However, its control efficacies against adults were much less than against larvae. Safety assessment of BtPlus against ecosystem was evaluated using young carp (Cyprinus carpio), a water flea (Daphnia magna), and a honey bee (Apis mellifera). BtPlus did not give any adverse effects on these nontarget organisms. Based on these results, BtPlus can be applied to control mosquitoes by direct aqueous application to paddy rice field.