Current investigations provide a comprehensive understanding of the occurrence and biodiversity of plant-parasitic nematodes (PPNs) in the major citrusproducing regions of Jeju Island, South Korea. Our survey identified five genera and five species of PPNs from 82 infested Citrus unshiu field samples collected across 116 sites in the Jeju provinces. Community analysis revealed the highest prevalence of PPNs (39.02%) at Namwon-eup, significantly driven by Tylenchulus semipenetrans, followed by Paratylenchus sp., Helicotylenchus sp., Meloidogyne sp., and Pratylenchus sp. Data indicate that all 82 sites were infested with T. semipenetrans (70.68%), marking a considerable increase in prevalence compared to previous surveys and posing a significant threat to citrus cultivation. The study results also demonstrate the influence of soil type on PPNs communities, revealing correlations between soil texture and nematode diversity. Citrus orchards cultivated in black clay loam soil exhibited significant PPN infestations. Overall, the PPN survey underscores the economic importance of monitoring citrus nematode infection rates and maintaining economic threshold levels in citrus production. It also emphasizes the need for developing effective management strategies to control PPNs, which are essential for maintaining crop yield and ensuring agricultural sustainability.

국내 들깨 재배지의 식물기생선충 감염현황을 조사하기 위해 2020년 1월 21일부터 10월 27일까지 8개 시군의 노지, 시설 들깨 재배지에서 채취한 토양 시료 51점을 분석하였다. 들깨 재배지에는 뿌리썩이선충류, 나선선충류, 뿌리혹선충, 위축 선충이 감염되어 있었으며, 뿌리썩이선충 (39%)과 나선선충 (55%)이 다른 선충에 비해 높은 감염률을 보였다. 들깨는 연작연수가 증가할수록 뿌리썩이 선충의 발생 빈도는 증가하는 추세를 보였으며, 11년 이상 연작하면 5년 미만일 때보다 발생 빈도가 2배 이상 증가하였다. 잎들깨와 종실용 들깨 재배지에 감염된 선충 종류와 밀도는 차이를 보였다. 들깨 검출 선충 가운데 경제적으로 중요한 뿌리썩이선충의 분자생물학적 종 동정 결과, 2속 3종 (Pratylenchus penetrans, P. vulnus, Pratylenchoides leiocauda)의 뿌리썩이선충이 감염되어 있는 것으로 나타났다. 본 연구 결과에 따라, 들깨 밭의 선충 관리 전략 수립 을 위해서는 뿌리썩이선충이 문제 선충이라는 점이 고려 되어야 할 것이다.

콩 재배지에서 콩씨스트선충(Heterodera glycines)과 반짝이씨스트선충(Heterodera sojae)의 지리적 분포에 관한 조사를 강원도와 충청북도 지역에서 수행하였다. 강원지역 10개시군, 67개 포장에서는 콩씨스트선충이 13개소, 반짝이콩씨스트선충이 5개소에서 검출되었고, 두 선충 혼 재하는 포장도 2곳이었다. 충북지역 9개 시군에서는 84개 조사 포장 중 27개소에서 콩씨스트선충이 검출되었고, 반짝이콩씨스트선충 4개소, 두 선충 혼재 발생지 5곳이었다. 강원, 충북 지역에서 콩씨스트선충류 검출 여부에 따라 발생하는 다른 식물기생성선충 속의 다양성과 우점도 지수 는 콩 재배지 사이에 유의한 차이를 나타내지 않았다. 콩씨스트선충과 토양 화학성 사이의 관계 분석에서는 결정계수가 낮게 나타났으며 콩씨스 트선충의 밀도가 높은 토양에서는 pH와 가용성 인산 함량이 높은 것으로 나타났다. 씨스트선충이 검출된 토양의 토성은 사질토가 전체 샘플의 60%를 차지하였다. 점토와 미사의 함량이 높은 토양에서는 콩씨스트선충의 밀도가 낮은 경향을 보였고, 모래 함량이 높은 토양에서 밀도는 높게 나타났다.

천마(Gastrodia elata Blume)는 난초과 다년생 기생식물로 곰팡이균과 공생하는 독특한 생활방식을 가진다. 천마의 지하근은 고혈압, 뇌졸중, 백혈병, 두통 특히 신경쇠약치료 등에 쓰이는 약용식물이다. 본 연구는 지구온난화가 천마의 생태적 반응에 미치는 영향을 알아보기 위해 보통의 야외 대기환경과 같은 대조구, 대조구보다 온도를 약 2℃ 상승시킨 온도상승구, 온도와 함께 대조구보다 CO2 농도를 약 2배 증가시킨 CO2+온도상승구에서 참나무 원목, 뽕나무버섯균, 종마를 함께 파종하고, 재배하여 생식기관과 지하근의 생물량을 비교 관찰하였다. 그 결과, 꽃대 수는 온도상승구> 대조구> CO2+온도상승구 순으로 적었다. 꽃대 길이는 온도상승구> 대조구> CO2+온도상승구 순으로 짧았다. 화서 길이는 대조구> 온도상승구> CO2+온도상승구 순으로 짧았다. 생식기관의 무게는 온도상승구> 대조구> CO2+온도상 승구 순으로 가벼웠다. 지상부의 생물량은 온도상승구> 대조구> CO2+온도상승구 순으로 낮았다. 생산된 근경의 수는 온도상승구> 대조구> CO2+온도상승구 순으로 적었다. 근경의 생물량은 온도상승구> 대조구> CO2+온도상승구 순으 로 낮았다. 이러한 결과는 온도만 올라간 환경조건에서는 천마의 생육은 활발하여 생산량이 증가하지만, 지구온난화조 건인 온도와 CO2 농도가 동시에 상승하는 조건에서는 천마의 생육이 불량하게 됨을 의미하는 것이다. 따라서, 천마의 성마와 종마 생산량을 높이기 위해서는 재배지의 적정지온 20~25℃를 유지하고, 높은 CO2 농도에 노출되지 않도록 하여야 할 것이다.

이 연구는 완전 기생성 침입종인 미국실새삼(Cuscuta pentagona)의 기주선호도와 기생부위를 야외현장과 기생유도 실험 통하여 확인하여 이들 식물의 기주다양성을 알아보고 잠재적인 위해성을 제시하고자 시도하였다. 미국실새삼의 기생은 구상나무와 신갈나무와 같은 목본성 식물종(12.1%)의 목질화가 되지 않은 소지나 잎에서도 관찰되었다. 미국실 새삼의 기주식물종은 국화과에 속하는 종이 가장 많았고, 과내 차지하는 기주식물종의 비율은 사초과, 마디풀과 그리고 콩과 등의 것에서 높았다. 기생 유도 실험을 통해 미국실새삼은 1종을 제외한 모든 식물에 기생할 수 있음이 확인됨으로 써 이 침입식물의 분포의 제한 요인은 분산과정이라는 것을 알 수 있었다. 기주식물의 감염된 부위는 줄기와 잎 두 곳에서 대부분 나타났고, 드물게 잎이나 줄기에만 나타나기도 하였다. 이 연구로 12개 과의 기숙식물 45종(12개 과의 초본식물 33종과 목본식물 12종)을 새롭게 추가하였다. 그 중에는 조와 같은 농작물뿐만 아니라 멸종위기야생식물 6종에도 기생하였고, 특히 후자의 경우에는 미국실새삼의 기생으로 식물체가 고사까지 당하는 경우도 있었다. 이는 미국실새삼이 잠재적으로 야생식물에게도 확산될 가능성이 높다는 것을 의미한다.

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.

전국의 콩밭에서 274점의 토양을 채집하여 식물기생성 선충의 종류와 밀도를 조사하였다. 콩씨스트선충은 제주도를 제외한 전국의 모든 토양에서 발견되었으며 검출율은 38%(25-51%)였고 씨스트 밀도는 토양 300 cm3 당 평균 46개(1-500)로 중요도 1등급으로 분류하였다. 뿌리혹선충(Meloidogyne spp.)의 검출율은 약 13%였는데, 경남, 전남, 제주 등 남부지역에서 높은 검출율(16-44%)을 보여 중요도 2등급으로 분류하였다. 내부기생성 선충인 뿌리썩이선충(Pratylenchus spp.)은 경기, 강원 등 북부지역에서 검출율(10-13%)이 높아지는 경향으로 중요도 3등급으로 분류하였다. 나선선충류인 Helicotylenchus는 특히 제주에서 검출율과 밀도가 높았는데(62%, 토양 300 cm3당 평균 571마리), 제주도는 국내 나물콩의 주산지로 앞으로 나선선충이 나물콩에 피해를 주기 않을까 우려되며 중요도 4등급으로 분류하였다. 위축선충류인 Tylenchorhynchus, 침선충류인 Paratylenchus, 주름선충류인 Criconema, Criconemoide, Mesocriconema, Ogma, 검선충류인 Xiphinema, 궁침선충류인 Paratrichodorus,Trichodorus 등은 국내 콩밭에서는 밀도와 검출율이 낮음으로 중요도 5등급으로 분류하였다. 다음의 선충들은 콩에 대한 피해가 확인되지 않았음으로 콩 기생성선충 목록에서 제외하고자 한다.; 식이성이 토양 조균류인 Tylenchus, Aphelenchus, 잎선충류의 Aphelenchoides, 줄기구근선충인 Ditylenchus, 벼뿌리선충, Hirschmanniella immamuri, 그 외 꼬리주름선충 Basiria graminophila, 곤봉선충류인 Psilenchus, Pseudhalenchus 등은 콩밭에서 드물게 발견이 되고 콩에 대한 피해는 알려져 있지 않음으로 콩 기생성선충 목록에서 제외하였다. 창선충 Hoplolaimus tylenchiformis는 콩에 상당한 피해를 끼치는 선충이나 표본미확인 상태임으로 콩 기생성선충 목록에서 제외하였다. 지금까지 국내 콩밭에서 총 26속 41종의 식물기생성선충이 보고되었는데, 이번 연구에서 선충 종류별 콩에 대한 중요도를 검토하고 우리나라 콩 식물기생성선충을 16속 30종으로 정리하였다. 국내 주요 콩 기생선충의 중요 우선순위는 1) 콩씨스트선충, 2) 뿌리혹선충, 3) 뿌리썩이선충으로 생각되며 4) 제주지역의 나물콩은 나선선충의 피해에 대한 검토가 필요하다.

Since 1956 the state of Florida has been implementing Nematology regulatory programs to protect high value crops such as Citrus spp and ornamental plants. The discovery of Radopholus similis, which causes a severe disease called “spreading decline” of citrus, during the 1950s, prompted the state to develop and implement strict phytosanitary and regulatory measures, including quarantine and a citrus nursery certification program to avoid further dissemination of the nematode. This also included two other major citrus pathogens, Pratylenchus coffeae and Tylenchulus semipenetrans. Also, ornamental and other plant nurseries certification programs were implemented to promote the export of plants to both national and international markets. These markets have restrictions against the movement of R. similis and other plant-parasitic nematodes that occur in Florida. Other plant-parasitic nematodes present in Florida, not regulated internally but regulated by other states and countries include Rotylenchulus reniformis and Belonolaimus longicaudatus. Regarding root-knot nematodes occurring in Florida, only Meloidogyne enterolobii is of regulatory concern because its ability to overcome the resistance of Mi-1, N, Rk, Tabasco and in omato, bell pepper, cowpea, sweet pepper and soybean, respectively, as well as other unidentified genes in soybean cultivars. The identification of M. enterolobii using morphological and morphometric characters, molecular markers, such as isozyme phenotypes (esterase and malate dehydrogenase) and mtDNA (C2F3/1108 primer set) will be discussed.

As nematologists we should ask ourselves how has nematode management changed or improved over the past 50 years. During this period we have lost over 12 key chemicals used as nematicides, some of which were highly efficacious. And in the meanwhile practically none have been added to our chemical control guides. This is problematic as we move into the future. For example, high value vegetable crops were highly dependent on methyl bromide for the past 40+ years. This product, whether used singly or in formulations mixed with chloropicrin, was highly efficacious against weeds, soilborne fungal diseases, and plant-parasitic nematodes. Now that the product is in very short supply, expensive, and allocated on the basis of critical use exemptions vegetable growers must begin to turn to other tactics. In 1994 scientist set a goal of developing a highly efficacious, reliable, and cost effective alternatives to methyl bromide but little success has been attained. The task was made difficult because of the lack of highly efficacious products, environmental constrains, worker protection issues, and newly imposed regulations that impact the use of soil fumigants. As a consequence we are moving toward a period when growers will be forced to choose less efficacious chemical products, if such products receive Federal registration, or choose other nematode management tactics. There has been only limited success with development of crop plants with resistance to plant-parasitic nematodes. Although promising, biological control has not yet made an impact on nematode management. Crop rotation, which has been listed as a control tactic for many years, remains one of the better choices for growers. Other tactics, e.g., solarization, organic amendments, and fallowing-flooding, etc have limited use. The pros and cons of each of these possible plant- parasitic nematode management tactics will be discussed.

To control Thrips tabaci in Korean leek and green onion which grow at vinyl house in IKSAN, Jeollabuk-do, the non-treatment was set as negative control. In general treatment group, 120 mesh gauze was installed on the side window after planting(May, 2nd) and, in spring, Orius strigicollis (1.0/m2) was grazed 3 times every 7 days from mid of May which is early development stage and In the mid of June, which is the peak stage, plant extracts were sprayed one time. In autumn, O. strigicollis was grazed 3 times every 7 days from mid of September which is early development stage, and in the mid of October, which is the peak stage, plant extracts were sprayed one time. The result shows that the leaf damage ratio was decreased by 22% in Korean leek and by 27% in green onion compared to the untreatment. And the control value of Thrips tabaci shows 78.7% in korean leak and 90.6% in green onion. The density control effect of Thrips tabaci was significantly controlled under max 6.2/plant in general treatment group compared max 25/plant in the untreatment and this result was similar in green onion. The yields by general treatment was increased by 85% in Korean leek and 56% in green onion, compared with non-treatment yields, which was 900kg/10a in Korean leek and 1,287kg/10a in green onion.

This study was conducted to identify plant-parasitic nematodes and determine the distribution pattern of the nematode species in citrus fruit orchards in Korea from April to August, 2008. Plant-parasitic nematodes were found in 139 among 178 soil samples. Tylenchulus semipenetrans was collected from 85 out of 94 Citrus unshiu orchards examined (90.4%). C. junos orchards infested with T. semipenetrans were 60 out of 84 (71.4%). However, proportion of dominant species between the two was different. At domestic Citrus orchards, it proved that T. semipenetrans was the most important plant-parasitic nematode from this study. The overall frequency of the plant-parasitic nematodes was positively correlated with the cultivation years. More alkaline soils tended to harbor more T. semipenetrans. However the correlation coefficient between the two was very low.

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.

This study was conducted to get basic information on the occurrence of plant-parasitic nematodes for the establishment of nematode management strategy in major potato production areas in Korea. Nationwide soil collection was done in 11 areas of Cheju, Yesan, Gimchun, Goryoung, Hong chun, Pyungchang, Gimjae, Milyang, Namwon, Gangnung, and Inje in 2004-2005. Root-knot nematode juveniles(J2) were detected in 30 samples among the 50 samples. The average density was 12-69 J2/100㏄ soil. Pratylenchus sp., Helicotylenchus sp., Ditylenchus sp., Tylenchus sp., and Tylenchorh-ynchus sp. were also detected in various locations, however, their densities were very low. Root-knot nematode females were collected from tomato roots inoculated with the potato field soils for PCR-RFLP identification. The females from Cheju, Milyang, and Goryung showed PCR products of 500 bp. And the Dra I restriction enzyme digestions showing 290 bp and 230 bp fragments confirmed their identity as Meloidogyne hapla.