The root-lesion nematode Pratylenchus spp. is the most important plantparasitic nematode due to its worldwide distribution, wide host ranges, and migratory endoparasitic characteristics. One population of Pratylenchus collected from the giant pussy willow (Salix chaenomeloides Kimura) in the Andong area as part of a nematode survey in Korea was characterized morphologically and by molecular methods. The analysis of morphological measurements and morphometric characteristics, as well as DNA sequencing of the rRNA large subunit (LSU) D2/D3 expansion segments and the internal transcribed spacer (ITS) gene sequence, confirmed the identity of this population as P. hippeastri. This study is the first report of P. hippeastri associated with Salix chaenomeloides in Korea and worldwide. Further studies on distribution and pathogenicity in different P. hippeastri host crops, such as grapevines, strawberries, and apples, are necessary. The taxonomic keys to 16 Pratylenchus species in Korea are provided.

Perilla plant is a special crop that is used as oilseed and food in Korea. Root lesion nematodes have caused great damage to perilla plants, so for effective management of root lesion nematodes, it is necessary to understand their ecology in perilla. In this study, we investigated the effect of temperature in the development of Pratylenchus penetrans (Pp) and Pratylenchus vulnus (Pv) when the nematodes infected the perilla plant. To estimate the effect of temperature, we assessed the reproduction factor (RF); final population/initial population (Pf/Pi) of these two nematode species. We used perilla plants as inoculated hosts and investigated the density of nematodes at 10 weeks after inoculation. As a result, the RF of Pp was highest at 20°C (0.41 (1st test), 2.2 (2nd test)) followed by 25, 30, and 15°C. The RF of Pv was highest at 30°C (9.84 (1st test), 31.39 (2nd test)), followed by 25, 20, and 15°C. Comparing the RF by temperature between Pp and Pv, Pv was higher than Pp at all temperatures used in the test. This study showed the optimal development temperature of Pp was 20-25°C and Pv was 30°C, respectively.

식물기생성 선충인 뿌리혹선충과 뿌리썩이선충은 국내에서 생강을 포함한 수입 구근류에서 주로 검출되는 검역대상 해충이다. 그러나 이 러한 선충류가 검출된 수입 생강의 경우 적절한 소독처리기준이 마련되어 있지 않아 폐기 및 반송처리로 인한 경제적 손실이 발생하고 있다. 본 연구에서는 생강에 침입한 검역 대상 선충의 사멸을 위한 식물소독처리 기준 마련을 위해 뿌리혹선충과 뿌리썩이선충을 사멸할 수 있는 온탕침지 법에 관하여 조사하였다. 그 결과, 뿌리혹선충과 뿌리썩이선충은 각각 48°C와 49°C에서 30초간의 온탕침지 처리로 사멸되었다. 52.5°C로 설정 된 60 L의 항온수조에 침지된 생강의 열전도 조사에서 생강 중심부와 내부 5 mm 두께의 온도가 50°C까지 도달하기까지는 각각 10~32분과 6~16분이 소요되었으며 51°C에서 30분 동안 온탕침지한 생강은 정상적으로 생육하였다. 본 결과를 바탕으로 뿌리혹선충의 유충을 생강에 인공 접종 한 후 51°C에서 30분간 온탕침지 하였을 때 처리한 선충이 모두 사멸되었다. 따라서 이상의 온탕침지 처리 조건은 생강에 영향을 주지 않고 두 종의 선충을 사멸시킬 수 있는 식물소독법의 기초자료가 될 것이다.

Electrolysis techniques(electrokinetic) generally have been used mainly to remove the inorganic salts like Cu, Pb etc. in the soil. In the organic living, the effects of electrolysis has a direct impact on survival by dissociation of the ions inside the cell and accumulation of energy within cells. In this study, It was evaluated for susceptibility to nematodes(Meloidgyne javanica, Pratylenchus coffeae) in accordance with the voltage, current and electrolyte concentration. Using the electrolytic bath and electrolyte material(TAE buffer, Nacl), the susceptibility of nematodes was evaluated in the range of 30 ~ 60V, 0.02 ~ 0.77A. Unusually, the high voltage and amperage did not increase the death rate of nematodes and the most resistant stage was not clear because sensitivity of each stage could not be distinguished. In 30V 0.52A, 0.70A, 0.72A, M. javanica eggs processed for 10 minutes did not hatch at all. In 30V 0.58A, M. javanica juveniles processed for 5 minutes were showed 100% mortality and in 30V 0.77A, P. coffeae juveniles processed for 5 minutes were showed highest sensitivity compared to other treatment range.

The most effective way to control plant parasitic nematodes are immersed in hot water, but the larger-scale processing is difficult to adjust a target processing temperature. Thermal equilibrium formula used to fit the processing temperature was very accurate and effective. Use of the thermal equilibrium formula was determined to be well suited on commercial scale(1400L volume chamber) hot water immersion treatment that should be quickly processed. 1000L of water based on 10%(111kg), 12%(136kg), 15%(176kg) filling ratio was applied in 48oC for 30min treatment and only 10%, 12% filling ratio was applied in 49oC for 10min. In 10% filling ratio, thermal equilibrium has been proceeding rapidly in 1-2 min, and no juvenile hatched in all treatments(at 48oC for 30min, at 49oC for 10min). In 12% filling ratio, though thermal equilibrium has been proceeding in 2 min, few juveniles were hatched in boundary temperature at 49.0oC. In 15% filling ratio, it took 7-8 minutes to reach thermal equilibrium after dipping. The result of applying the two treatment conditions(at 48oC for 30min, at 49oC for 10min) to commercial scale field experiment showed nematodes were almost completely eliminated in hooker chive roots. However, some of living nematodes were observed in 15% filling ratio treatment.

This study was carried out to find out the effect of water stress (RDI) on multiplication of plant parasitic nematodes on grapevines. The responses to irrigation treatments were not significantly different in relation to new root growth, root dry weight and total number of parasitic nematodes, however significant differences in the density of Meloidogyne javanica in the soil between daily irrigation and the treatment with water stress (RDI). The main effect of inoculum type was significant, and the water treatments significantly affected total root growth between the nematode treatments, as well as M. javanica density in the soil in the nematode treatments. The daily irrigation treatment with Pratylenchus spp. had the least root growth but was not significantly different to root growth in the RDI treatment with Pratylenchus spp. Similarly with RDI, there was no significant difference in root growth in treatments receiving combined nematode inoculum between daily irrigation and RDI. However, root growth in treatments receiving M. javanica in RDI was significantly greater than those receiving M. javanica with daily irrigation. Under RDI treatment, the number of M. javanica recovered from soil receiving M. javanica inoculum was significantly greater than under daily irrigation. However, there was no significant difference between daily irrigation and RDI in the number of M. javanica or Pratylenchus recovered from soil receiving the combined treatment or in Pratylenchus recovered from soil in the Pratylenchus treatment.

Root-lesion nematodes, Pratylenchus sp., are recognized as one of the most important plant parasitic nematodes. They infest various crop plants and cause severe root damages which lead to the yield loss of agricultural crops. There are 72 species recorded in the world, but 14 species in Korea. Soil samples were collected from chrysanthemum cultivars in various regions. Morphological and molecular diagnosis firstly recognized two species as Pratylenchus kumamotoensis and P. pseudocoffeae in Korea. Morphologically, P. kumamotoensis characterized by pharyngeal gland lobes overlapping with intestine dorsally. P. pseudocoffeae, which is similar with P. coffeae, but pharyngeal gland lobes are longer than P. coffeae. In molecular diagnosis, nucleotide sequences of D2-D3 region (700-800 bp) within 28S rDNA and ITS region including ITS1, 5.8S and ITS2 (700-1,000 bp) between 18S and 28S rDNA were determined from collected samples. NCBI database comparison of D2-D3 of P. kumamotoensis and P. pseudocoffeae were 99% similar with those of corresponding species, respectively. ITS of P. pseudocoffeae was 99% similar within species. ITS sequence of P. kumamotoensis was firstly determined in this study. Distribution of P. kumamotoensis was only reported in Japan but P. pseudocoffeae is present in Japan and USA. Here we firstly report the presence of these two species in Korea.

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.

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.

Root-lesion nematode (Pratylenchus vulnus) and pin nematode (Paratylenchus sp.) were detected with high population density at the spray chrysanthemum greenhouse in Gumi, Gyeongbuk. The average density of P. vulnus and Paratylenchus sp. was 667 and 716 nematodes per 100 g soil and P. vulnus density were distributed 87% to the depth of 0~30 ㎝ in greenhouse. When spray chrysanthemum cv Chopin, was transplanted in September 2004 in greenhouse, P. vulnus were 854 nematodes/100 g soil in planting and increased 14,985 nematodes/100 g soils and 1g root after 10 weeks in harvest. Shoot weight and shoot height of spray chrysanthemum decreased 24.8% and 8.0% compared with non-infested P. vulnus after 10 weeks in greenhouse.

A survey was conducted to find out the major plant parasitic nematode in Chrysanthemum morifolium fields in Korea from May to June in 2005. A genus of Pratylenchus was determined as the most important plant parasitic nematode based on analysis of total 50 samples from 8 cities of chrysanthemum field. Pratylenchus showed 86% occurrence rate and average numbered 1,095 per 200㏄ soils and Ig root. Five Pratylenchus isolates, "Muan", "Masan", "Tean", "Gumi", "Jeongup", were selected for the molecular identification of the species of Pratylenchus, and ITS and D3-28S ribosomal DNA were amplified by PCR. For the ITS, only" Muan" isolate was differentiated by total 1 kb PCR amplification, which was 200 bp larger than all the other isolates. There was no size variation in amplified D3-28S rDNA and all isolate represented approximately 320 bp of PCR product. Sequence data of D3-28S rDNA were analysed by MegAlign program in DNASTAR software and phylogenetic tree was constructed. Sequence homology was 100% between "Gumi" isolate and "Tean" isolate and "Jeongup" isolate was also close to these isolates by 99.7% sequence homology. "Gumi", "Tean" group and "Jeongup" isolate were determined to be closely related to Pratylenchus vulnus by 96.7% and 96.3% similarity in respectively. D3 sequence of "Masan" isolate was 100% identical to P. penetrans, and "Muari" isolate showed 99.7% similarity to P. brachyurus. This result was congruent with the branch divergence pattern shown in phylogenetic tree.

차나무뿌리썩이선충(Pratylenchus loosi)이 국내에서 처음으로 전라남도 명암군과 제주도 남제주군의 차나무 뿌리와 주변 중에서 발견되었다. 차나무뿌리썩이선충의 두부주름은 2개이며 암컷의 길이는 433-646이고, a ＝ 29.1-37.5, b ＝ 5.1-6.4, c ＝ 15.0-21.3, vulva (%) ＝ 73.0-85.4였다. 수컷의 몸길이는 408-512 였으며 a ＝ 36.1-40.0, b ＝ 4.8-6.7, c ＝ 17.0-19.0, spicule ＝ 14.1-18.0였다. 구침의 길이는 11.6-18.0였으며, 측선의 갯수는 4개였다. 저정낭은 정자로 차 있으며, 모양은 둥근 고치모양 또는 직사각형 모양이다. 꼬리의 형태는 가늘고 끝이 둥글거나 뾰족하다.

본 연구는 뿌리썩이선충(Pratylenchus vulnus)이 옥수수뿌리조직을 침입했을 때, 조직의 해부학적.생화학적 변화를 밝힘으로써 식물과 선충의 상호관계를 이해하고, 이들 정보를 바탕으로 선충저항성 작물의 육종 및 선별에 활용하기 위함이다. 옥수수뿌리 표피를 뚫고 들어온 선충은 뿌리 피층에 자리를 잡고, 세포벽을 파괴하면서 다른 세포로 이동한다. 마침내 선충들은 피층의 내피와 세근의 기부에 밀집했다. P.vuinus의 암컷들은 세포내에 공간(cavity)을 형성하여 그 속에 알을 낳는 습성을 지니고 있다. 선충에 의한 주된 피해양상은 세포벽이 파괴되고 부서져서 공간을 형성하는 것으로 나타난다. 이러한 현상은 세근의 기부에서도 관찰된다. 선충의 피해로 야기된 옥수수 뿌리의 생화학적 변화는 선충접종구와 무접종구간 총단백질양과 esterase활력조사를 통해 비교.분석되었다. Denaturing gel 상에서 총단백질양의 비교는 유의한 차이를 나타내지 않았고, esterase 의 pattern 및 활력에서도 유의할 만한 차이는 발견되지 않았다.