• The Korean Journal of Pesticide Science
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• v.5 no.4
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• pp.40-44
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• 2001

Pesticide actual usage in fruit crop cultivation was surveyed, and usage trends of individual pesticides were evaluated to provide data for the development of indicators of environmental impact. The amount of pesticide used for fruit crops indicated the order of fungicide>insecticide>herbicide unlike the case of paddy rice. The fungicide rate of total usage was 72% in apple cultivation. Top ranking fungicides used on fruits were Mancozeb, Propineb, Thiophanate-methyl and the main insecticides were Mancozeb, Propineb, Thiophanate-methyl. The usuage by formulation types showed the order of WP>EC>SL>SC>SP>WG. Pesticide usage (a.i.) per hectare by different fruits was citrus 48.6kg, apple 27.1kg, pear 18.6kg, persimmon 17.5kg, peach 11.3kg and grape 9.2kg. Comparison of pesticide usage (a.i.,kg/ha) in some fruit crops between Korea and USA indicated that more pesticides were used for citrus, pear and peach in USA than Korea while more pesticides were used in Korea than USA for apple.

• The Korean Journal of Pesticide Science
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• v.12 no.3
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• pp.283-290
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• 2008

Baculoviruses have been used to control some serious lepidopteran pests. However, their narrow target insect spectrum and slow efficacy are main limitations to be used in various applications. This study introduces a technique to overcome these limitations by inhibiting insect immune defence to enhance the viral pathogenicity. Polydnaviruses are an insect DNA virus group and symbiotic to some ichneumonid and braconid endoparasitoids. Cotesia plutellae bracovirus (CpBV) is a braconid polydnavirus and encodes several immunosuppressive genes. We selected seven CpBV genes and recombined them to wild type Autographa California multiple nucleopolyhedrovirus (AcNPV). A bioassay of these seven recombinants indicated that most recombinants had similar or superior efficacy to wild type AcNPV against beet armyworm, Spodoptera exigua, and diamondback moth, Plutella xylostella. Recombinant AcNPV with CpBV-ELP was the most potent in terms of lethal time by shortening more than 2 days compared to wild type AcNPV. This recombinant was further proved in its dose-dependent pathogenicity and its efficacy by spray application on S. exigua infesting cabbage cultivated in pots. We discussed the efficacy of CpBV-ELP recombinant AcNPV in terms of suppressing antiviral activity of target insects.

• The Korean Journal of Mycology
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• v.46 no.3
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• pp.333-344
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• 2018

Selection of the optimal culture medium and evaluation of the antimicrobial activity against various phytopathogens were performed for four entomopathogenic fungal isolates with excellent insecticidal and antimicrobial activity against the two-spotted spider mite (Tetranychus urticae), green peach aphid (Myzus persicae), and gray mold (Botrytis cinerea). The optimal medium was selected by measuring the amount of blastospore production and the antifungal activity of the culture medium. On the basis of these experiments, GY medium was selected for Beauveria bassiana 2R-3-3-1 and Metarhizium anisopliae 4-2, SD3, and PDB medium for B. bassiana SD15. The antimicrobial activity test against other phytopathogens indicated that all four isolates showed high antifungal activities against Colletotrichum acutatum and Sclerotinia sclerotiorum. However, for Phytophthora capsici and C. fructicola, only M. anisopliae SD3 showed a high antifungal activity against P. capsici, and the other three isolates had little activity. Antibacterial activity against Clavibacter michiganensis subsp. michiganensis was high in two isolates of M. anisopliae but not in two isolates of B. bassiana. Thus, it was confirmed that entomopathogenic fungi effective for pest control could be effectively used as a control agent for various plant diseases.

• Korean journal of applied entomology
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• v.55 no.3
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• pp.257-266
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• 2016

Subtropical insect pests expand their habitats by migration to temperate zones along with global climate change. A subtropical insect pest, Maruca vitrata, is infesting leguminous crops including azuka beans in Korea and gives significant economic damages. Its great genetic variation raised an issue of the origin of a Korean M. vitrata population. To understand the genetic character of the Korean population, its cytochrome oxidase subunit 1 (cox 1) gene was sequenced and phylogenetically analyzed with other regional populations. The world populations of M. vitrata were grouped into three clusters: Asia-African, American, and Oceanian. The Korean population was classified into Asia-African cluster. To characterize the insecticide susceptibility of the Korean population, seven different insecticides (4 neutoxic insecticides, 1 insect growth regulator, 2 biopesticides) were assessed. Young larvae of M. vitrata were relatively susceptible to all tested insecticides. However, old larvae were much less susceptible than young larvae. No test insecticides effectively (> 50%) killed the old larvae of M. vitrata within 7 days.

• Korean journal of applied entomology
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• v.47 no.1
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• pp.37-44
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• 2008

Oriental fruit moth, Grapholita molesta, is a serious pest on apples. To control this pest in an environmentally friendly method, mating disruption strategy using sex pheromone has been developed. Area-wide application of mating disruption has been needed to be effective, with little understanding on how much size of apple cultivating area should be treated in one time application of the mating disruption technique. On this matter, we needed to determine a minimal mating active zone of G. molesta that should be applied with mating disrupters to be effective. Molecular markers to discriminate a specific population should be developed to trace population migration for reproductive behaviors. Here we developed two effective molecular markers using random amplified polymorphic DNA (RAPD) technique. Different field populations of G. molesta, based on locations and seasons, were analyzed with these markers. In a specific location, G. molesta populations varied in genetic composition with different seasons. Different local populations showed differential variation according to their relative distances among apple orchards. In overall, genetic variation among different populations became lessen with progression of seasons.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.431-435
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• 2015

Riptortus pedestris (Fabricius) is one of the important insect pests of leguminous crops, which occurs in most areas of South Korea. It is hard to distinguish each generation in crop fields since not only the longevity of adult R. pedestris is long but also the developmental period is short. Especially, the 2nd generation adults cause enormous damage to soybean while the occurrence time is synchronized with the podding stage of soybean. Controlling the 1st generation of R. pedestris helps to decrease the damage by decreasing the 2nd generation density. This study was conducted to distinguish between the 1st generation and the overwintering generation by using differences in body coloration which is dependent on the day-length during the nymph stage. In addition, the difference was verified by the population dynamics model of R. pedestris. The occurrence time of 1st generation adults could be considered when the summer form is 20% or more. These results will be used for beneficial management decisions to reduce the 2nd generation population.

• Korean journal of applied entomology
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• v.62 no.3
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• pp.117-124
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• 2023

The management of Ricania spp. is difficult because this pest has a wide host range and diverse habitats such as agricultural, suburban, urban, and forested areas. However, the researches for Ricania spp. management have been focused on only agricultural crops. Thus, it is required to determine the arboreal host preference of Ricania spp. at the surrounding areas of the farms to increase its management efficiency. To determine its host preference at arboreal plants, we reviewed the previous studies and investigated the densities of Ricania spp. at woody plants with high ecological importance but insufficiently studied. This study identified 120 species in 53 families of arboreal hosts of Ricania spp. Only Cornus officinalis and Styrax japonicus were preferred by all developmental stages of Ricania spp. The host preference of Ricania spp. was changed according to its developmental stages. This phenomenon would be caused by that each developmental stage of Ricania spp. would prefer different parts of woody plant, and require different nutrients for its survivor and reproduction. These results of this study could be helpful to make a plan of comprehensive management strategies for Ricania spp.

• Korean journal of applied entomology
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• v.41 no.4
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• pp.269-277
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• 2002

Ecological studies on entomopathogenic nematodes are required to increase control efficacy against target insect pests and to obtain basic information for mass production. Thus, effect of temperature and nematode concentration on infectivity and reproduction of Steinernema carpocapsae Pocheon and that of exposure time and soil depth on infectivity were examined using Galleria mellonella larvae. Infectivity and reproduction were examined at five temperatures, 13, 18, 24, 30 and 35$^{\circ}C$ with seven concentrations, 0, 5, 10, 20, 40, 80 and 160 infective juveniles (IJs)/larva. Temperature and nematode concentration influenced infectivity and reproduction of S. carpocapsae Pocheon. Although G. mellonella larvae were killed by S. carpocapsae Pocheon at all given temperatures and nematode concentrations, mortality was higher at 24$^{\circ}C$ than other temperatures. Lethal time of G. mellonella by S. carpocapsae Pocheon was shorter with increasing temperature and nematode concentrations. S. carpocapsae Pocheon was not established in G. mellonella at 13 and $35^{\circ}C$. Time for the first emergence from G. mellonella cadaver was longer $18^{\circ}C$ (about 20 days) than 24 and $30^{\circ}C$ (about 5 days). The highest number of progenies was obtained at $24^{\circ}C$ with 80IJs/1arva, i.e., $18.8$\times$10^4$IJs were produced from a larva. In the exposure time assay, G. mellonella death was recorded in 10 minutes when 300 IJs were inoculated per larva. When S. carpocapsae Pocheon was inoculated at the rate of $10^{9}$ IJs/ha to G. mellonella at the depth of 0, 2, 5 and 10 cm of sand columns, 100% mortality and similar sex ratio were observed but number of established IJs in cadaver was decreased with deepening the soil depth. The results indicated that optimum temperature for infectivity and reproduction of S. carpocapsae Pocheon was $24^{\circ}C$ In addition, S. carpocapsae Pocheon was effective to target insects within 5 cm from the soil surface.

• The Korean Journal of Pesticide Science
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• v.17 no.3
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• pp.200-205
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• 2013

Mating disruption experiments were evaluated and compared in several pheromone traps and sex pheromone composition ratios at commercial chestnut garden for developing alternative control method of D. punctiferalis. The highest attractive was shown in Delta traps at the effective sex pheromone ratio of 75:25 (E10-16:A1:Z10-16:A1). Comparisons of domestic and imported pheromone constituents were not significant difference in 90:10 (E10-16:A1:Z10-16:A1). But, there was significant difference in sex pheromone ratio of 75:25. D. punctiferalis was caught the highest number in Gongju area for attractive test using pheromone trap. Attractive effects with dose of pheromone were showed the highest at 2.5 mg/lure and 1 mg/lure in Gongju area and Cheongyang area respectively. However, there was no significant difference among pheromone dose in Buyeo area. These data could be useful for eco-friendly managing of D. punctiferalis in the chestnut farm.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.440-447
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• 2013

F. occidentalis (WFT, western flower thrips) is a major pest in artificial chrysanthemum houses. Nnumber of WFT attracted to yellow sticky trap was highest at trap plant and lowest at 15 and 20m places away from trap plant. Number of WFT attracted to yellow stick trap when trap plant was placed in chrysanthemum house 30 days after planting (resident WFT) was 4.4~7.7 times more than at 5 and 10 m places away from trap plant and when trap plant was placed in chrysanthemum house immediately after planting (resident WFT) was 5.7~9.4 times more at 5 and 10 m places away from trap plant. Number of WFT between the place trap plant located and unlocated was undifferent when cultured chrysanthemum formed flower. In case of the plot that trap plant and natural enemy was used simultaneously, number of WFT was highter then chemicals plot. In case of the plot that trap plant and chamicals (chemicals was sprayed on trap plant only) WFT was controlled in trap plant place only but density of WFT on 5m and 10m places away from trap plant was increased. Therefore, WFT could be controlled effectively by use of trap plant (flowering yellow chrysanthemum) and natural enemy simultaneously.