• Journal of Korean Society of Forest Science
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• v.104 no.2
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• pp.332-335
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• 2015

Taphrina wiesneri, a pathogen of cherry witches' broom, is highly pathogenic to Prunus yedoensis Matsumura which are widely planted in parks and streets in South Korea. In order to control the disease, it is crucial to know the life cycle of the fungus. We attempted to detect the fungus tentatively overwintering in shoots and branches of cherry trees both having witches' broom and healthy before flowering and leafing in spring using PCR with species-specific primer set (TwITSF and TwITSR). Genomic DNAs were extracted from the symptomatic and the asymptomatic shoots or branches. Results indicated that T. wiesneri is present in leaf buds and inner bark not only in symptomatic branches but also in the asymptomatic branches in diseased trees. However, the fungus was not detected in flower buds of the symptomatic trees and any samples of healthy trees.

• Asian Journal of Turfgrass Science
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• v.11 no.3
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• pp.185-191
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• 1997

Biological control of turfgrass insect pest Blitopertha orientalis, forest insect pests, Agelastica coerulea, Meganola melancholia, and Glyphodes perspectalis,vegetable insect pests, Plutella xylostella and Agrotis segetum were conducted with entonopathogenic fungus, Metarhizium anisopliae J-22 isolated from black pine forest soil in Cheju province. Mortality of B. orientalis larvae was 53.3% at the rate of 3.4 $\times$ 1O 7 conidia /ml. A. coerulea and M melancholia larvae showed 100% mortalities at 9.6 $\times$ 106 conidia /ml and 2.7 $\times$ 10 7 conidia /ml as well. However, G. perspectalis larvae were not dead even at 4$\times$ 1O 7 conidia /ml. On the other hand, M anisopliae J-22 was effective against P. xylostella larvae showing 100% mortality at 4 $\times$ 10 7 conidia /ml. KEy words:Entomopathogenic fungi, Biological control, Metarhizium anisopliae, Pathogenicity,Blitopertha orientalis, Agelastica coerulea, Meganola melancholia, Glyphodes perspectalis,Plutella xylostella, Agrotis segetum.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.361-370
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• 1982

The effects of climatic factors on organisms lire variable and complex, and it, however, can be interpreted in terms of those on the distribution and those on the population densities. The distribution of an organism may largely be determined by the temperatures, except some temporal organisms which are depended on the air mass movements. Population density of an organism is determined by various climatic factors, such as previous winter temperature, temperature of growing season and rainfall. The start of growing season of the rice plants has been shifted to earlier since last decade in Korea. This may mean that the overall climatic condition during the growing season might be considerably different from those in past years, and such a difference in climatic conditions might have close relation with the recent status of the diseases and insect pests through direct effects on the physiology and population dynamics of the organisms, as well as through on the biotic associations of the pest organisms. The white back planthopper and brown planthopper have become the key insect pests in Korea in recent years. They are migratory and have high reproductive pontentials and more generations than average residential insects. The synchronization of the migrants and physiological condition of the rice plants seems to be the important factors in relation to the recent outbreaks of these insects; the high reproductive rate can be obtained with the growth stage of rice being 30-50 days after transplanting. The modication of the microclimate associated with high plant density and some other introduced new cultural techniques also have some relation with the outbreak. The key diseases of the rice are the blast disease, sheath blight and the bacterial leaf blight. For the rice blast, the seedling blast and leaf blast during the early growing season and the neck blast, have become more serious, the former may be related to hotbed nursery and the later may be related to the high humidity in early August, and synchronization of the heading time which has been shifted to early part from middle or late part of August. In general, for the rice diseases, the development of the new races have been the most serious which are largely resulted from the introduction of the new varieties, but it also seems to be related with the prolonged periods of the favorable condition associated with the shifted growing seasons. In general, the diseases and insect pest problems have become much more variable and complex, and control measures should be based on the thorough knowledge of the ecology of the pest organisms, that is, effects of various environmental factors on the disease cycle; spore release, spore deposition, infection, colonization and sporulation of the disease organisms, and those on the development, reproductive potentials, dispersal, age specific responses of the insects. The well organized real-time pest management systems, such as alfalfa weevil management system developed at the Purdue University in U.S., is the prime importance for the implementation of the pest management principles.

• Korean Journal of Environmental Agriculture
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• v.37 no.2
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• pp.125-134
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• 2018

BACKGROUND: Green peach aphid (Myzus persicae) is an insect pest that significantly affects crop production. A number of pesticides have been used for aphid control, but their concerns on insect resistance and food safety have required alternative methods for pest management. In an effort to find for an alternative approach to aphid control, we screened plants extracts and examined their potentiality as insecticidal bio-resources. METHODS AND RESULTS: Two hundred and ninety eight plant extracts were examined for insecticidal activity against the aphid, and the best candidate among them was chosen for further study. The extracts from Cinnamomum camphora was determined to be the best candidate exhibiting insecticidal activity more than 60% at a level of $1,000{\mu}g/mL$. GC/MS analyses detected camphor, borneol, 4-terpineol, ${\alpha}$-terpineol and caryophyllene oxide as major compositions from the extracts obtained by hydrodistillation. Caryophyllene oxide exhibited the highest insecticidal activity with a $LC_{50}$ value of $237{\mu}g/mL$. Camphor lowered significantly the $LC_{50}$ value of caryophyllene oxide and increased largely its concentration in aphid, suggesting that camphor played a role in enhancing the insecticidal activity of caryophyllene oxide. CONCLUSION: This study suggested that camphor and caryophyllene oxide may be used as an insecticidal bio-resource for insect control against green peach aphid.

• International Journal of Industrial Entomology and Biomaterials
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• v.18 no.2
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• pp.57-61
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• 2009

Three years($2004{\sim}2007$) survey was conducted on the incidence of silkworm diseases namely, Grasserie, Flacherie, Muscardine and Uzi fly, a silkworm pest with 150 sericulture farmers in the districts of Chittoor and Anantapur in Andhra Pradesh. The data revealed that grasserie and flacherie incidence were maximum in summer season and minimum in winter season whereas muscardine was observed high in winter season in both the areas and rarely in rainy season in Chittoor and Anantapur districts. An improvement of 11.16 and 7.6 kg cocoons/100 dfls were recorded in the batches of PM xCSR2 Diseases free layings(Dfls) reared in rearing houses disinfected with 2% bleaching powder and Ankush, a plant based bed disinfectant applied as per schedule, respectively. The Uzi fly incidence was suppressed by 61.02% in batches where the integrated package was adopted for control of Uzi fly infestation.

• Korean journal of applied entomology
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• v.47 no.3
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• pp.273-286
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• 2008

Road-map for the environmental friendly integrated pest management(IPM) of insect pests was drawn up on the strawberry vinyl-houses of farmer's field. Major insect pests were occurred Tetranychus urticae and Aphis gossypii during the strawberry plant seeding in the vinyl house and open field. Also, same insect pests were occurred in the vinyl house during harvesting season of strawberry. For the control of T. urticae and A. gossypii, Phytoseiulus persimilis and Aphidius colemani as natural enemies were input to the vinyl house, respectively. However, because these natural enemies could not control insect pest populations, acaricide and insecticide were sprayed. Then natural enemies were input again in the vinyl house. Natural enemies could not endure the intense cold and differences of temperature and relative humidity between day and night during strawberry harvesting season. So, their behavior and control activity of pests were more decrease than pests. Firstly, natural enemies are input in the vinyl house during the early breeding season of strawberry, secondly, acaricides and insecticide are sprayed for the control of mites and aphids, respectively, during the middle breeding season in the hard winter. Finally, natural enemies are re-input in the vinyl house during the middle and late breeding season.

• Natural Product Sciences
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• v.23 no.4
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• pp.235-238
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• 2017

Colorado potato beetle is a most destructive insect pest of potato throughout the world. Although utilization of chemical insecticides is a main method for management of this pest, their negative side-effects such as threat to humans and the environmental pollution prompted researchers to search for natural alternatives. Recently plant essential oils with low or without side-effects against noun-targeted organisms and with high availability were considered as safe bio-pesticides. In the present study, toxicity of essential oil of Iranian lemongrass, Cymbopogon citratus Stapf, was evaluated against 3th instar larvae and adults of Colorado potato beetle by a leaf dipping method. Results displayed essential oil had notable toxicity against both larvae and adults after 24 and 48 h exposure times. Probit analysis revealed $LC_{50}$ values (lethal concentration to kill 50% of population) with 95% confidence limits were 10.32 (9.17 - 11.72) and 7.76 (6.80 - 8.74) ${\mu}l/ml$ for larvae and 6.27 (4.82 - 8.15) and 4.35 (3.24 - 5.62) ${\mu}l/ml$ for adults after 24 and 48 h, respectively. Based on regression analysis, a positive correlation between log concentration of essential oil and insect mortality was achieved. Results indicated C. citratus essential oil can be candidate as a natural alternative to the harmful chemical insecticides in the management of Colorado potato beetle.

• The Korean Journal of Mycology
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• v.37 no.2
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• pp.139-143
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• 2009

Several entomopathogenic fungi have been exploited to be developed into biological control agents in insect pest management. The beet armyworm, Spodoptera exigua, is a serious insect pest infesting various crops, but not effectively controlled by commercial chemical pesticides due to its high insecticide resistance. A fungal isolate was isolated from S. exigua larvae collected from cabbage field in Andong, Korea. The fungus could be cultured in potato dextrose agar. Larvae of S. exigua injected with the cultured conidia showed a potent entomopathogenicity. To identify the fungus isolate, its internal transcribed space (ITS) and surrounding partial 18S/28S regions were sequenced. The ITS sequence was highly matched (99%) to that of Nomuraea rileyi. Morphological characters of its hyphae and conidia were well fit to those of known N. rileyi. This study reports the first record of an entomopathogenic fungus, N. rileyi, in Korea.

• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.2
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• pp.137-141
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• 2005

Though many insecticides are commercially available, development of resistance, pest resurgence and effects on non-target organisms led to the search for alternate insect pest management (IPM) strategy based on larval growth and reproductive fitness. Reproductive potential of insects depends on its acquiring of vitellogenic competence which is under hormonal control. Exogenous application of analogues of JR (JHAs) and ecdysterone could derail normal development and reproduction in insects by manipulating an array of physiological processes. In the rice pest, brown planthopper, Nilaparvata lugens, JHA, hydroprene induced metathetely from the fifth (final) instar nymphs in an age-dependent manner. Day 0 of the final instar showed highest sensitivity to induce this abnormal development. Adults emerged from treated day 3 nymphs looked normal. Both the morphotypes were reproductively incompetent and showed partial to complete sterility. Pre-adult exposure of the ovarian tissue to hydroprene suppressed mitotic division of germinal cells and induced abnormalities in the later s1ages of growth and differentiation of ovary in N. lugens. More over the nymphal exposure to hydroprene inhibited patency changes of follicular epithelium and affected competence of the follicles for yolk sequestration. In the absence of ovarian growth and oocyte differentiation, germarium found disintegrated, trophic core regressed and terminal oocytes resorbed. Hydroprene exposure to newly ecdysed brachypterous females did not affect ovarian development and egg production. Proper larval-adult transition appeared as a. prerequisite for vitellogenic competence in N. lugens for which the ovarian tissues must be exposed to ecdysterone in the internal milieu devoid of JH.

• Microbiology and Biotechnology Letters
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• v.27 no.5
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• pp.415-418
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• 1999

Thecodiplosis japonensis is an important insect pest in pine trees and hard to be controlled by chemical pesticides due to its characteristic life cycle. Experiments were conducted to determine the pathogenicity and growth temperature of several entomopathogenic fungi as potential microbial insectcides for T. japonensis. Beauveria bassiana SFB-SC and Paecilomyces fumosoroseus SFP-198 were highly pathogenic against T. japonensis. B. bassiana SFB-SC had also pathogenicity against a beneficial insect Bombyx mori. Growth rate and pathogenicity of P. funmosoroseus SFP-198 under 15$^{\circ}C$ was higher than those of B. bassians SFB-SC. These results indicated that P. fumosoroseus SFP-198 is a potential microbial control candidate for control of T. japonensis.