Monochamus alternatus (M. alternatus) and Monochamus saltuarius (M. saltuarius) are major vectors for Bursaphelenchus xylophilus in South Korea. When an adult, they are easily distinguishable by several morphological classification. However, it is difficult to identification between M. alternatus and M. saltuarius when they are larvae as they have very similar morphological characters. Thus, they are not easily distinguishable without expertise about Cerambycidae taxonomy. Furthermore, during epidemiological investigation, sometimes, adults or larvae would not be founded in death pine trees. For these reasons, in this experiment, we are able to identified between M. alternatus and M. saltuarius by mitochondrial 12S rRNA gene primers that are specific to 12S rRNA gene fragment of M. alternatus using larvae tissue and frass. Moreover, we had examined whether vectors that were already escaped from dead pine tree have Bursaphelenchus xylophilus or not by multiplex PCR using larva frass that was remained in dead pine tree.

Since first reported in 1988 the Pine Wilt Disease has been established and spreaded nearly nationwide in South Korea, causing tremendous economic damage in pine forests. The pine wilt nematode (Bursaphelenchus xylophilus), causing the Pine Wilt Disease, in Korea is known to be transported by two insect vectors that are Monochamus alternatus Hope and Monochamus saltuarius Gebler. Currently the pest management strategy largely relies on pesticide application and infected tree clearing. The aim of the present study was to search for early larval parasitoids of M. alternatus using the sentinel log infested with the cerambycid eggs. Only one braconid species was collected and identified as Spathius verustus Chao. Two to ten wasp larvae attached and fed on one host larva. Parasitism rate was 55.5 to 59 % in Jinju site, while 1 to 18.1 % the other sites. Sex ratio was female-biased (female : male = 18.9 : 1). The S. verstus has potential to be use as parasitic natural enemy of M. alternatus.

The Baermann funnel method requires three to four Kimwipes tissues for clean nematode extraction. To find more efficient and economical nematode extraction paper, 14 different kinds of tissue papers were tested and compared with Kimwipes tissues. Nematode species used in the extraction efficiency test were juvenile (J2) of Heterodera spp., J2 of Meloidogyne spp., Pratylenchus spp., Rhabditis spp., Acrobeloides spp., Panagrolaimus spp., Poikilolaimus spp. and Diplogasterida. Extraction efficiency varied between 42.0 to 88.8%. Considering costs, extraction efficacy, and cleanness, one sheet of Pulling Kitchen Towel (MONALISA Co., Korea) is selected.

It is difficult to identification between Bursaphelenchus spp. and Pine Wood Nematode (PWN) by morphological characteristics without expertise about nematode taxonomy. Furthermore, Baermann funnel method, which is nematode extraction method from wood chips or soil, requires at least 24 hours to extract nematode that is unsuitable to rapid diagnose the Pine Wilt Disease (PWD). For these reasons, the aim of this experiment is not only to improve accuracy of a PCR based method but also to reduce total experiment time for detection Bursaphelenchus spp. and PWN in the wood chips of PWD infected pine tree. In this experiment, we had been employed two PCR primer sets, which were originated from PWN specific Internal Transcribed Spacer (ITS) sequence region and Bursaphenchus spp. universal mitochondrial Cytocrome Oxidase subunit I (mtCOI) sequence region in order to discrimination between Bursaphelenchus spp. and PWN at the same PCR reaction. This experimental procedure was able to reduce experiment time and cost as well as to improve accuracy of detection than previous PCR based detecting method by not using Baermann funnel method and commercial genomic DNA extraction kit but using direct pine wood chips lysis method.

A nematode, which showed entomopathogenicity, was isolated from Exomala orientalis in Korea, and then identified as Rhabditis blumi. Pathogenicity of R. blumi was evaluated against major cruciferous insect pests, including Artogeia rapae, Mamestra brassicae, and Plutella xylostella. In Petri-dish tests, insect mortality was dose and time dependent, which increased with dose (0–80 dauer juveniles/larva) and time increments. In greenhouse tests, P. xylostella larvae were most susceptible to nematodes, with insect reduction rate of 88.0 %. The rate varied with vegetable species and persistence time of live nematodes on vegetable leaves after spraying. The aeration rate was an important parameter for cultivation of the nematode R. blumi. A sufficient DOT level in the culture using an air-lift bioreactor should be maintained. The nematode growth rate increased with an increasing DOT level and/or bacteria uptake rate. The maximum nematode yield of 1.75 x 105 per ml was obtained under an aeration rate of 6 vvm.

Oncholaimid nematode, Oncholaimus secundicollis Shimada, Kajihara and Mawatari, 2009, is firstly reported based on a comparative morphological study. The present specimens of O. secundicollis are collected from rocky intertidal seagrass on the eastern coast of Korea. Oncholaimus secundicollis is distinguished from all of its congeners by the following combination of morphological characteristics: buccal cavity large with thick cuticular wall and three teeth, left subventral tooth larger than right subventral or dorsal teeth, and the presence of two remarkable precloacal papillae with nine pairs of cloacal setae and single ventral tail papilla with two pairs of short setae. In this study, we provide taxonomic description and illustration of unrecorded species of the genus Oncholaimus.

Three unrecorded species of free-living marine nematodes, belonging to genus Enoplus Dujardin, 1845 collected from rocky intertidal seagrass on the eastern coast of Korea, are described and illustrated. Enoplus taipingensis Zhang and Zhou, 2012 is characterized by longer body size, a series of lateral setae throughout the tail in male, the presence of trumpet-shaped precloacal supplement with well-dilated proximal end, and the presence of spicules with five to eight semicircular plates. Enoplus meridionalis Steiner, 1921 is characterized by the presence of trumpetshaped precloacal supplement with slightly dilated proximal end, paired massive spicules, and tail with two pairs of stout terminal setae. Enoplus mammillatus Timm, 1959 is easily distinguished from the congeners by narrow tubular-shaped precloacal supplement. In this study, we provide detailed morphological features of three Enoplus species by differential interference contrast microscopy and scanning electron microscopy. This is the first report on the species of the genus Enoplus from the Korean waters.

표고버섯좀나방(Morophagoides moriutii)은 최근 버섯 에 심각한 피해를 주는 해충으로 유충이 골목이나 종균, 자실체를 직접 가해하여 생산량을 감소시키고 상품성을 저하 시킨다. 표고버섯좀나방의 환경 친화적 방제에 이용 할 수 있는 가능성을 알아보기 위하여 국내 토양에서 탐 색된 토착 곤충병원성 선충 Steinernema carpocapsae GSN1 계통의 접종 농도별 병원성, 침입수, 증식수를 표고 버섯좀나방의 령기에 따라 조사하였다. 선충의 표고버섯 좀나방에 대한 병원성은 접종농도가 높을수록 증가하였다. 표고버섯좀나방 2령충, 3령충에서 유충 한 마리당 선충 감염태 유충(3령충) 80마리 접종부터 100%의 높은 병원 성을 나타내었고, 표고버섯좀나방 4령충은 한 마리당 선 충 감염태 유충 40마리 접종부터 100%의 치사율을 나타 내었다. 선충의 표고버섯좀나방 유충 체내로의 침입수는 접종 농도와 령기가 높을수록 선충의 침입수도 증가 하였 다. 선충 감염태 유충 5마리 농도 처리에서는 2령충 1.3마 리, 3령충 1.7마리, 4령충 1.8마리 였으나, 160마리 농도 처리에서 2령충 12.3마리, 3령충 21.1마리, 4령충 22.5마 리로 조사 되었다. 끝으로 표고버섯좀나방 유충 한 마리 당 침입한 선충의 증식수는 같은 령기에서는 선충의 접종 농도가 많아질수록 증식수가 증가하였다. 또한 표고버섯 좀나방의 령기에 따라 선충 증식수의 차이는 많았는데, 선충 감염태 유충 160마리 처리농도에서는 각각 표고버 섯좀나방 2령충이 6,335마리, 3령충이 21,660마리, 4령충 이 88,700마리로 조사되었다. 따라서 토착 곤충병원성 선 충 S. carpocapsae GSN1 계통은 표고버섯좀나방의 생물 적 방제를 위한 방제제로 활용할 가능성이 높음을 알 수 있었다.

소나무재선충은 현재까지 도입된 국가의 토착수종인 소나무류를 모두 치사시키는 것으로 알려져 있으나, 고사목으로부터 추출 배양된 계통 중에는 소나무에 피해를 주지 않는 계통이 존재한다. 이러한 저병원성 계통 선충의 사전접종이 고병원성 소나무재선충에 대한 소나무의 저항성에 미치는 영향을 조사하기 위하여 연구가 수행되었다. 치수에 저병원성 소나무재선충을 선접종한 결과, 선접종에 의하여 소나무재선충에 대한 저항력이 유도되었다. 그 유도저항성은 1년 후까지 유지되었으며, 저병원성 선충의 반복 감염은 보다 저항성 유도 효과가 큰 것으로 나타났다. 소나무재선충에 의하여 고사한 후 경과기간이 3개월 이하인 피해목 및 피해진행목에서 분리된 선충은 모두 고병원성이었으며, 고사 후 2-3년이 경과한 벌채목에서 분리된 선충 5계통 중 4계통은 저병원성이었다. 저병원성 선충이 소나무 치수에 인공접종 되었을 때 초기 정착률은 고병원성 선충과 차이가 없었으나, 접종 30일 후에 수목내의 부위별 개체수를 조사한바 저병원성 선충의 증식률은 고병원성보다 현저히 낮았다. 저병원성 선충의 잿빛곰팡이병 균사배지에서의 선충증식 속도는 계통에 따라 차이가 있었으며, 증식속도가 빠른 계통은 대체로 고병원성 선충의 증식속도와 차이가 없었다.

최근 5년 동안 식물검역 현장에서 검출된 뿌리썩이선충속 선충을 분류하여 Pratylenchus crenatus, P. fallax, P. kumamotoensis, P. panamaensis, P. penetrans로 동정하였다. 이 종들의 진단형질은 구순부의 주름 수, 두부의 형태, 구침의 길이, 수컷의 유무, 측대의 구조, 수정낭의 형태, 후부자궁낭의 길이, 미부의 형태 등을 포함한다. 이들의 사진과 측정치 및 형태적 특징을 기술하였다.

Thermal death kinetics was examined to develop a heat treatment method to control the Pine wood nematode, Bursaphelenchus xylophilus, in wood packing materials for export goods. To determine the feasibility of microwave irradiation as an alternative treatment, we performed laboratory experiments on the blocks (200x200x250mm) of Douglas-fir artificially infested with live adults with subsequent 2.45GHz microwave energy irradiation. The 100% mortality of treated Pine wood nematode was achieved above 64℃ of the measured wood temperature, regardless of irradiated time. All measurement points in the blocks reached 64℃ within 84-312 seconds with microwave irradiation by wood weight. Likewise, the 100% mortality of nematodes were observed by hot water treatment on 62℃. We need further experimental verification, but commercial microwave (2.45GHz) treatment is a feasible alternative to conventional heat treatment to control Pine wood nematode on the wood packing materials for export goods.

과채류 재배지에서 발생하는 식물기생성 선충의 방제를 위해 충남 공주의 오이 재배지와 충남 부여와 논산, 경남 진주의 딸기 재배지, 전남곡성의 메론 재배지역에서 시설재배와 노지 재배를 하고 있는 농가토양을 채취하여 선충을 분리, 동정한 후 각 지역별 토양에서 abamectin 1.68% SC, cadusafos 3% GR, dazomet 98% GR, fosthiazate 30% SL, BA12011 SL 등 약제들의 선충에 대한 밀도억제 효과를 알아보기 위하여 실내실험과 포장실험을 실시하였다. 대부분의 지역에서 채취한 토양 시료에 분포하고 있는 식물기생성 선충의 평균밀도가 약제처리 후 감소하는 것으로 확인되었지만, 부여의 경우 fosthiazate 처리시 Pratylenchus spp.가, 곡성의 경우 fosthiazate, abamectin, cadusafos, dazomet 처리시 Pratylenchus spp.에 대하여 토양 내 평균 밀도가 상승하였다. 또한 BA12011 처리시 약제처리 후 다른 약제와 비슷한 수준의 개체군 평균밀도를 보였으며, 특히 공주 토양에서는 fosthiazate의 약제처리 효과보다 모든 종에서 높은 방제효과를 확인하였다. 각 지역에서 채취한 토양에 약제처리를 한 후 난낭 형성을 확인한 결과, abamectin의 경우 부여와 진주의 토양에서 효과를 보였고, BA12011은 논산과 곡성, dazomet는 공주에서 난낭 형성을 억제하는 효과를 확인하였다. BA12011을 가지고 오이재배지에서의 방제효과를 살펴본 결과, Meloidogyne spp., Pratylenchus spp., Helicotylenchus spp.의 평균 밀도가 감소하였고, 2차 처리시보다 1차 처리시 평균 밀도의 감소율이 높은 것으로 보아 초기 단계의 방제의 중요성을 확인할 수 있었다.

선충절대기생세균(Pasteuria penetrans)이 감염되어 있는 온실토양을 이용하여 세균의 내생포자가 땅콩뿌리혹선충(Meloidogyne arenaria) 유충 표면에 부착하는데 대한 온도의 영향에 대해 시험하였다. 갓 부화된 뿌리혹선충 2령충(J2)을 페트리디쉬 내의 토양에 접종한 후 20℃, 25℃, 30℃, 35℃에서 7일간 처리하였다. 모든 온도에서 내생포자의 J2 부착률은 모두 100%로 나타났으나 J2당 내생포자 부착수는 25℃에서 28.3개로 가장 많았으며 30℃, 20℃ 및 35℃에서 각각 J2 당 20.2, 18.6 및 13.6개로 낮아졌다. J2를 접종하기 전에 세균이 있는 토양을 온도 별로 10일간 전처리하였을 때 내생포자 부착률은 실온에서의 60%에 비해 -30℃, 4℃, 40℃, 50℃ 및 100℃에서 각각 25.0, 31.7, 8.3, 5.0 및 0%로 현저하게 낮아졌다. J2 당 내생포자 부착수도 실온에서의 5.3개에 비해 -30℃, 4℃, 40℃, 50℃ 및 100℃에서 각각 3.5, 4.3, 1, 1, 0개로 적었다. P. penetrans 세균의 내생포자를 뿌리혹선충 종별로 J2에 부착 시험한 결과 땅콩뿌리혹선충에서는 100%였으나 당근뿌리혹선충(M. hapla)과 고구마뿌리혹선충(M. incognita)에서는 모두 0%로 본 균주는 뿌리혹선충 종에 대해 기주선호성을 가진 것으로 나타났다.

본 연구에서 사용한 QRD(Quadratic Residue Diffusor) 마이크로파는 일반적인 마이크로파와 달리 파장의 위상차를 변화시켜 균일한 살균을 유도할 수 있어 저전력으로 효과를 높일 수 있는 새로운 기술로 알려져 있다. 따라서 친환경적이고 에너지 소비가 적은 QRD 마이크로파를 이용하여 식물공장에 이용되고 있는 배지를 멸균할 수 있는 가능성에 대한 기초적인 연구를 수행하여 얻은 결과는 아래와 같다. 마이크로파의 조사 출력에 따른 배지의 외적변형은 배지 내의 수분의 함유량과 마이크로파 출력을 2~8kW까지에서 우레탄스폰지와 암면은 외적변형이 전혀 일어나지 않은 것으로 확인되었다. 그러나 PDA고체배지는 2kW 출력에 60초와 180초에서는 배지가 녹지 않았고, 그 외 처리에서는 전부 배지가 녹았다. Bacillus sp.와 Burkholderia sp.에서 마이크로파의 조사 출력과 처리시간에 따른 균주 표면 온도는 차이가 나타났다. 마이크로파의 조사 출력과 처리시간에 따른 균주 멸균 실험은 마이크로파의 출력 2kW에서 시간과 관계없이 Bacillus sp.와 Burkholderia sp.는 모두 자라고 있는 것을 확인하였고, 마이크로파의 출력 6kW에서는 Burkholderia sp.의 60초 처리를 제외한 모든 실험구에서 멸균되었으며, Bacillus sp.는 모든 실험구에서 사멸되었다. 마이크로파의 출력 8kW에서 시간과 관계없이 Bacillus sp.와 Burkholderia sp.는 모두 멸균되었음을 확인하였다. 균주를 각각의 배지에 오염시킨 후 마이크로파를 처리한 배지 내의 온도는 처리시간 60초 지난 뒤에는 우레탄스폰지와 암면배지에서의 온도가 100℃ 이상으로 유지되어 대체로 60초 부터 멸균이 가능한 것으로 판단되었다. 따라서 식물공장내에 가장 문제가 되고 있는 Bacillus sp.와 Burkholderia sp.는 본 실험에서 사용된 QRD 마이크로파로 충분히 멸균될 수 있을 것이라 판단된다.

Three acetylcholinesterases (ACEs) were identified from the pinewood nematode, Bursaphelenchus xylophilus, and named BxACE-1, BxACE-2, and BxACE-3. Sequence comparison with known ACEs in conjunction with three-dimensional structure analysis suggested that all BxACEs share typical characteristics of ACE but show some differences in the peripheral anionic site. BgACE-3 was most predominantly transcribed, followed by ACE-1 and ACE-2. Immunohistochemistry using anti-BxACEs antibodies revealed that BxACE-1 is most widely distributed whereas BxACE-2 exhibits more localized distribution in neuronal tissues. BxACE-3 was detected from entire body together with some limited tissues, and determined to be soluble. Kinetic analysis of in vitro expressed BxACEs revealed that BxACE-1 has the highest substrate specificity whereas BxACE-2 has the highest catalytic efficiency with BxACE-3 having the lowest catalytic efficiency. Interestingly, presence of BxACE-3 in the pool of BxACEs significantly reduced the inhibition of BxACE-1 and BxACE-2 by inhibitors. Knockout of BxACE-3 by RNAi significantly increased the toxicity of nematicides, supporting the protective role of BxACE-3 against these toxicants. Taken together, BxACE-1 appears to be the major ACE with the function of postsynaptic transmission whereas BxACE-3 has been evolved to acquire the function of chemical defense. BxACE-2 appears to play a role in post-synaptic transmission in specialized neurons.

Recently, a rapid movement of agricultural products with an extensive international trading and climate change have led to an increased attention to nematodes as having regulatory significance. With the increase of global dispersal of pests, new diagnosis methods are required for a rapid and reliable species and/or biotype identification to restrict introduction of the pests. Recently, novel molecular diagnostic techniques provide clues to solve taxonomic problems associated with conventional species identification. In this articles, we proposed various molecular diagnostic techniques to complement the limitation of morphological taxonomy.

Influences of low concentration of heavy metals (As, Cd, Cu and Pb) on the nematode community structure were examined to assess the changes of the soil ecosystem for a short period of time. Notable increases of heavy metal concentration on the experiment soil were found on the maximum and their 4-1x concentration treatment of all heavy metals after 18weeks. Overall abundance of the nematodes increased regardless of kinds of heavy metal and their concentrations. Also there were no significant differences in the nematode abundance among all treatments of heavy metals except the abundance of c-p 4 in the maximum treatment of Pb. The number of nematode genus found in soils treated with heavy metal solutions also increased compared to that of the genus of the initial soils; however, no significant differences in richness were observed among the treatments of all heavy metals. In maturity and diversity indices of the nematode community, no significant changes occurred in the soils treated with heavy metal solutions with a few exceptions such as MI2-5 and ΣMI2-5 for Pb, and MI2-5 for As. Significant decreases of the ecological indices in the treatments with highly concentrated heavy metal solutions were noticed in MI2-5 and ΣMI2-5 for Pb, and MI2-5 for As, respectively. All of these results is supposed that the maturity and diversity of the nematode community may be decreased in soils contaminated with heavy metals such as Pb and As at relatively low concentrations of a short period of time, which may be derived from differential effects of heavy metals at low concentrations on the growth and development of the nematodes with different c-p values and trophic types. In the analysis of food web structure, only structure index (SI) was significantly lowered in soils irrigated with the heavy metal solutions of Pb and As, but enrichment index (EI) and channel index (CI) were not, suggesting that stressful soil conditions might be provided to the soil food web structure governed by direct toxic effects of heavy metals differential to nematode populations with different trophic type sandc-p values. Analyses of correlation coefficients also suggest that the influence of heavy metals at low concentrations, especially by Pb, maybe most prominent on the nematodes of c-p2-5, including fungivores, providing stressful soil environments.

The pinewood nematode, Bursaphelenchus xylophilus is a serious forest pathogen in many countries including Japan, China and Korea. To minimize the environmental problems caused by synthetic chemicals broadly utilized in the control of B. xylophilus, we estimated the nematicidal potency of 63 aliphatic compounds against B. xylophilus by measuring their inhibition activity against acetylcholinesterases (ACE, EC 3.1.1.7) of B. xylophilus (BxACEs). In the primary inhibition assay using B. xylophilus crude protein, C6, C9, C10 2E-alkenal C12 alkanoic acid were observed the > 45% BxACE inhibition rate and they were subsequently estimated the inhibition rate against three recombinant BxACEs. Whole compounds showed the high inhibition rate against BxACE-1 and BxACE-2. Interestingly, C6 2E-alkenal and C12 alkanoic acid exhibited the high inhibition rate against BxACE-3 which would be insensitive to ACE inhibitors.

콩 씨스트 선충은 콩 수량에 가장 심각한 피해를 입히는 선충이며, 콩 씨스트 선충으로 입는 피해가 연 간 전 세계적으로 9백만 메가그램이나 되는 것으로 추정되고 있다. 콩 씨스트 선충은 식물 영양분을 먹어 뿌리의 성장을 지연시키고 근류균의 고정을 억제함으로서 수량의 감소를 가져 오게 된다. 콩 씨스트 선충을 방제하는 근본적인 방법은 저항성 품종을 재배하거나 윤작을 하는 것이다. 유전적으로 콩 씨스트 선충의 다양한 레이스들과 상업적 품종들의 제한된 저항성 품종들이 오랜 시간에 걸쳐 레이스 전환을 가져왔고, 이러한 이유로 콩 씨스트 선충의 방제가 매우 어려운 실정이다. 이 논문은 콩의 중요성, 콩 씨스트 선충, 콩 씨스트 선충 저항성에 대한 연구현황, 그리고 전망에 관해 고찰하였다.

The genus Pratylenchus is considered as one of the most important plant-parasitic nematodes around the world because of its broad spectrum host ranges and worldwide distribution. 72 species of root-lesion nematodes have already been described from various parts of the globe. Among all of them, only 5 species are regulated as a target species in quarantine inspection. As the importation of target items inspecting nematodes are surely increasing every year, detection rate of nematodes in quarantine also increased. However, the rate of species identification has been decreased due to lack of related information. The species belonging to genus Pratylenchus are shown very low identification rate because we have specimens and information about only 10 domestic species and 5 regulated species. In this study, we identified the species in the genus Pratylenchus and obtained related information for application in the quarantine field. Species identification was performed with extracted nematodes from plants obtained in the recent quarantine inspection. Newly identified species were 5 species including Pratylenchus crenatus, P. fallax, P. kumamotoensis, P. panamaensis and P. penetrans. The photos, measured value and morphological characters of each species are provided.