This study was conducted to clear the regional difference in the resistance development of the spirodiclofen 36% WP, an acaricide of tetronic acid class, against two-spotted spider mite, Tetranychus urticae occurred in apple orchard since 2007. Two-spotted spider mite was collected from eight regions in the Chungnam, Chungbuk and Gyeongbuk that were major apple cultivation in Korea. An bioassay was investigated the ovicidal activity to compare with the degree of resistance development of this pest. The managed orchard in Sancheok-myeon, Myeongseo-ri, Chungju was controlled by several different acaricides from 2001 to 2008, and spirodiclofen WP was used for the last seven years. LC50 of spirodiclofen WP was estimated as 19.4 ppm in managed orchard, it showed as high as 2.6-fold (resistance ratio) comparing to those of susceptible strain showed as 7.5 ppm. LC50 of spirodiclofen WP against etoxazole-resistant two-spotted spider mite, gained from Chungbuk National University, was proved in 8.1 ppm. This observation indicates that spirodiclofen WP did not occurred in cross resistance with etoxazole SC. Other two regions in Chungju, the resistance ratio against spirodiclofen WP showed as 2.5- and 2.3-fold, respectively. In Chungnam, Gyeongbuk, it has been limited the resistance ratio under 3-fold, respectively.

The susceptibility of the Blattella germcanica (L.) in the Republic of Korea (ROK) to insecticides was evaluated under laboratory conditions using 12 insecticides currently used by the local public health centers and/or pest control operators in the ROK. The insecticides included seven pyrethroids and five organophosphages. Based on their LD50values, the order of susceptibility of B. germanica adults to the insecticides was chlorpyrifos-methyl, profenofos, and chlorpyrifos with the values of 0.07, 0.29, and 0.88 ㎍/♀, respectively. The least susceptibility was obtained with tetramethrin at LD50 of 7.39 ㎍/♀. In the comparative resistance test, the resistance ratios (RR) of 12 insecticides were compared to each other using field collected B. germanica adults in Seoul between 1993 and 2007. Blattella germanica demonstrated higher RRs to pyrethroids such as λ-cyhalothrin, and low RRs among the organophosphates. Among the pyrethroids, λ-cyhalothrin had the highest RRs of 111 and 129 fold differences at LD50 and LD90 values, respectively. Among the organophosphates, profenofos was observed to have the highest RRs of 4 and 15 fold differences at LD50 and LD90 values, respectively. However, there were no significant differences in susceptibility to tetramethrin, chlorpyrifos, and fenitrothion. Blattella germanica was more susceptible to pyridafenthion showing a 0.7 fold difference in a resistance rate (RRLD50), respectively. Resistance ratio of tetramethrin was low, but susceptibility was also not high.

It has been reported that the antimicrobial susceptibility patterns of viridans streptococci vary according to geographical region. Although several studies on the antibiotic resistance of viridans streptococci in foreign countries have been reported, little is known about the distribution of resistance among viridans streptococci in Korea. In this study, 88 isolates of viridans streptococci from Korean students' dental plaque were identified as 12 different species. The susceptibility of these isolates to 8 antibiotics was investigated. The in vitro antibiotic activity of penicillin G, ampicillin, vancomycin, streptomycin, gentamicin, erythromycin, amoxicillin, and tetracycline was measured by the broth microdilution method. The range of the minimum inhibitory concentrations (MIC), MIC50, MIC90, and the percentage of the susceptible isolates were determined. Streptococcus mutans and Streptococcus salivarius were susceptible to the 8 antibiotics. Isolates with resistance to vancomycin, streptomycin, and amoxicillin were not found. The overall resistance rates of the 88 isolates to penicillin G, ampicillin, gentamicin, erythromycin, and tetracycline were 12.5%, 62.5%, 62.5%, 26.1%, and 26.1%, respectively.

The susceptibility of five stink bugs species collected soybean fields in Milyang in 2006 to seven insecticides was evaluated using electric auto-sprayer. The insecticide deltamethirn had the lowest median lethal concentration (LC₅₀) of 0.4 to 2.3 ppm regardless of stink bugs species while phenthoate had the highest concentration for one-banded stink bug (Piezodorus hybneri), green stink bug (Nezara antennata), sloe bug (Dolycoris baccarum), and brown marmorated stink bug, (Halyomorpha halys), and fenthion for bean bug (Riptortus clavatus). The average LC₅₀ for stink bugs to seven insecticides was lowest at 7.5 ppm for R. clavatus, followed by 16.6 ppm for H. halys, 17.6 ppm for D. baccarum, 19.1 ppm for N. antennata, and 28.4 ppm for P. hybneri. The relative tolerance ratio (TR), which is the TR of 90 percent lethal concentration (LC₉₀) of stink bugs to the recommended concentration, was the lowest in fipronil for R. clavatus, P. hybneri and D. baccarum, fenitrothion for N. antennata, and fenthion for H. halys. The relative average TR was lowest at 0.09 for R. clavatus, followed by 0.26 for D. baccarum, 0.30 for N. antennata, 0.37 for P. hybneri, and 0.39 for H. halys. Therefore, insecticides susceptibility was highest for R. clavatus and lowest for P. hybneri while the relative average TR was lowest for R. clavatus and highest for H. halys. Accordingly, it is expected that stink bugs can be effectively controlled with by spraying insecticides in soybean field because the relative average TR value of stink bugs was below 1.0, indicating high susceptibility of stink bugs to insecticides.

본 연구는 박리방지 첨가제를 혼입한 아스팔트 혼합물의 수분민감성에 대한 특성 평가 방안을 제시하고자, 기존의 수침 시험을 개선한 3가지 종류(Hc, Vs, F-T)의 수침 방법을 통하여 생석회, 소석회, 1종의 액상 박리방지 첨가제를 혼입한 각 아스팔트 혼합물에 대한 수분민감성의 거동 특성을 분석하였다. 실험방법은 AASHTO TP-9에 규정된 간접인장시험(Indirect Tensile Test, IDT)을 통한 크리프시험 (Creep Test), 회복탄성계수시험(Resilient Modulus Test) 및 강도시험(Strength Test)을 수행하였다. 분석방법으로는 미국 플로리다 대학의 Roque에 의해 제안된 에너지비(Energy Ratio, ER) 개념을 사용하여 박리방지제의 사용에 따른 효과 및 수분민감도 특성을 평가하였다(Roque, 2004). 시험결과, 수분처리 방법 에 따른 아스팔트 흔합물의 물성 변화뿐만 아니라 박리 방지 첨가제에 따른 물성 변화가 현저하게 나타났다. 또한 누적 수분 손상에 의해 발생되는 균열에 대한 저항성이 각 첨가제 및 수분처리 방법에 따라 변화됨을 나타내었다. 이를 토대로 Energy Ratio를 분석한 결과 약 10~30% 정도의 균열 저항성 변화가 나타났다.

Tetranychus evansi Baker & Pritchard occurs on solanaceous plants, and causes serious damage to a variety of crops in Africa and Europe; it has not been reported from Japan. Tetranychus takafujii Ehara & Ohashi was found on Solanum nigrum L. in Japan in 2001 and described as a new species in 2002. It is considered to be a Solanaceae-specialist too and it is feared to become a severe pest on solanaceous crops, once it invades them. Because T. takafujii is morphologically very similar to T. evansi, doubt has arisen about the difference between these two species. Here we avoid the issue of taxonomy and focus on a solution for the potential problems that may arise when either of the species invades solanaceous crops. The present study determines the susceptibility of three T. takafujii populations from Japan and six T. evansi populations from various countries to 11 acaricides. The LC50-values of all nine populations tested were lower than the recommended concentration of every acaricide. These results suggest that mites from all nine populations can be controlled with acaricides when they occur on crops.

This study was performed to investigate the toxicity of 39 registered insecticides to the susceptibility, systemic effect, and residual effect and control effect against Pine sawyer beetle, Monochamus saltuarius. Eleven kinds of chemicals such as fenitrothion, fenthion, phenthoate, phosphamidon, dinotefuran, actamiprid, clothianidin, thiacloprid, thiamethoxam, esfenvalerate + fenitrothion, and fipronil were showed 100% insecticidal activity both in body spray and twig dipping bioassay. Among these chemicals, fenitrothion and fenthion were showed 100 % insecticidal activity when sprayed at 4000 times diluted solutions, and phenthoate, thiacloprid, thiamethoxam and fipronil were showed 100% insecticidal activity when sprayed at 2000 times diluted solution. Root systemic effect was showed 100% mortality in phosphamidon, clothianidin, thiamethoxam, and 77.7% in thiacloprid. In residual effect, fenitrothion and thiamethoxam were showed 80% mortality fifteen days after treatment (DAT), and fenthion, phosphamidon, clothianidin were showed 80% mortality ten DAT, fenitrothion, thiamethoxam, fipronil showed 100% mortality in seven DAT, thiacloprid was showed 100% mortality in three DAT. Fenthion and phenthoate were showed 100% mortality one DAT. In the control effect, 6 kinds of chemicals were showed 100% mortality one DAT and all chemicals showed 100% mortality three DAT.

This study was conducted to investigate the regional difference in the degree of resistance development of the spirodiclofen 36% WP, an acaricide of tetronic acid class, against two-spotted spider mite, Tetranychus urticae occurred in apple orchard. Two-spotted spider mite was collected from every three regions in the Chungbuk and Gyeongbuk. To compare with the degree of resistance development, this pest was focused on the ovicidal activity (when treated acaricide). The managed orchard in Sancheok-myeon, Myeongseo-ri, Chungju was controlled by several different acaricides from 2001 to 2007, and spirodiclofen WP was used for the last six years. In case of managed orchard, LC50 of spirodiclofen WP was 14.0 ppm, it showed 1.6 fold (resistance ratio) that was estimated as considerably low level resistance ratio comparing to the those of susceptible strain showed in 8.7 ppm. LC50 of spirodiclofen WP against etoxazole-resistant two-spotted spider mite, gained from Chungbuk National University, was investigated in 7.5 ppm. This observation indicates that spirodiclofen WP did not occurred in cross resistance with etoxazole SC. At other regions in Chungju, the resistance ratio against spirodiclofen WP showed as 1.0 and 1.4 fold, respectively. In Gyeongbuk, one region of Yecheon and two regions of Yeongju, it showed as 0.7, 0.8 and 0.9 fold, respectively.

본 연구는 북한산 국립공원을 대상으로 산사태 발생인자들에 대한 공간정보를 구축하였으며, 중첩분석 및 합산평가 매트릭스분석을 이용한산사태 취약성 지도 및 생태적 위험 지표 작성을 통해 향후산사태 재해 예방을 위한 기초자료를 제시하고자 하였다. 산사태 평가 인자로는 사면경사, 사면방향, 경사길이, 토양배수, 식생활력도(NDVI), 토지이용도가 선택되었으며, 공간데이터베이스는 30m×30m 해상도로 구축되었다. 분석결과, 우이동 및 도봉계곡 일대의 산사태 취약성이 높은 것으로 분석되었으며, 생태적 위험도는 도봉계곡, 용어천계곡 및 정릉계곡, 평창계곡 등이 높은 것으로 분석되어 향후 이들 지역의 관리계획 수립 시 산사태 위험에 대한 영향도 고려되어져야 할 것으로 판단된다.

One hundred isola tes of Staphylococcus aureus were obtained from feces samples of patients with food poisoning. The a ntibiotic susceptibility against vari ous antibiotics was examined by disc diffusion test . The S. aureus isolates had 92% resista nce to peni cillin. They also had 30% resistance to ampicillin and erythromycin. respect ively. The percentage of re sistance to oxacillin was 14%. Three vancomycin resistant isolates were also found. The minimal inhibitory co ncen tra ti on(MIC)s of antibiotics were examll1ed Antibiotics-intermediate S a ureus isolates were not det ected by disc dif fu sion t est

Laboratory tests were conducted to determine the susceptibility of the alfalfa weevil, Hypera postica to Korean entomopathogenic nematodes, Steinernema carpocapsae GSN1 strain (ScG), S. glaseri Dongrae strain (SgD), Heterorhabditis bacteriophora Hamyang strain (HbH), and Heterorhabditis sp. Gyeongsan strain (HeG) at the petri dish assay. The larval mortality of H. postica was significantly different depending on nematode species and treatment concentration. SgD and HeG strain were more effective against H. postica larva than ScG and HbH strain. When SgD and HeG strain were treated with the rate of ＞20 infective juveniles (ijs) per alfalfa weevil larva, mortality was ca. 77.5-100% at the late instars of H. postica in 3 days. The number of established nematode was significantly different depending on nematode species, whereas number of progeny was not significantly different. The mean number of established ijs of SgD strain in a host was the highest at 80 ijs by 30.2. The highest progeny number of HeG strain was 2,671.5 with 80 ijs. All nematode strains were not parasitic entirely to H. postica adults. These results show that alfalfa weevil late larva is highly susceptible to Korean entomopathogenic nematodes in the laboratory.