Southern root-knot nematode (SRKN, Meloidogyne incognita) is known to be responsible for annual economic losses of 38.2 million USD in cucumber cultivation in Korea. Nematicides are frequently used to manage SRKN in plastic greenhouses. A field experiment was conducted to assess the effect of a soil fumigant (dimethyl disulfide, DMDS) and a non-fumigant (fluopyram, FL) against SRKN during the winter fallow season in a greenhouse from October to December. Nematicidal efficacy was assessed at 43 days after treatment, and the root gall index was measured 4 months after transplanting cucumber seedlings. DMDS effectively reduced second-stage SRKN juvenile density with 91% control efficacy, while FL showed no control efficacy against SRKN. Root gall index values were significantly different (p=0.020) in DMDS treatment and controls at 1.0±0.00 and 4.3±0.58, respectively. This study showed that DMDS could be considered an effective nematicide for controlling SRKN in the fallow period in winter.

A survey of plant-parasitic nematodes (PPNs) was carried out in medicinal crop cultivated fields from July to August in 2023. Three-leaf ladybell, Adenophora triphylla var. japonica is a highly valued medicinal plant that is used to treat or prevent bronchitis, cough, cancer, and obesity in Korea. A. triphylla plants with small root-galls were observed in a field of Yeongju Agricultural Technology Center, which were identified as a root-knot nematode. Additional morphological and molecular analyses studies were performed and identified as Meloidogyne hapla, Northern root-knot nematode. Population densities of M. hapla ranged from 20~30 nematodes per 100 cm3 of soil. M. hapla was detected at lower densities in soil compared to other infected host crops, but there are concerns about damage to M. hapla since A. triphylla is cultivated for more than two years once planted. Our results indicate that A. triphylla roots damage by M. hapla were identifed, it is necessary to prepare control methods such as registration of applicable nematicides and crop rotation.

Root-knot nematode (RKN), Meloidogyne incognita, inflicts significant greenhouse crop damage, causing over 40% economic losses. While chemical agents effectively control RKN, they leave harmful residue in soil and crops. To address this issue, we investigated soil-derived entomopathogenic fungi (EPF) in this study. We assessed the nematicidal impact of ten EPF species through in vivo and in vitro tests. Beauveria bassiana JEF-503 exhibited nematicidal effectiveness exceeding 65% in both experimental settings. In a semi-field test using greenhouse pots, we experimented with the application of B. bassiana JEF-503 suspension during tomato growth, which is an uncommon practice in comparison to chemical treatments due to residue concerns. B. bassiana JEF-503 was applied during transplantation, and the same application was repeated four weeks later. JEF-503 One-time and abamectin treatments were used as control groups. The JEF-503 two-time application notably reduced root damage compared to single JEF-503 or abamectin treatment. In conclusion, JEF-503 offers a promising, residue-free, and environmentally friendly alternative to chemical agents for RKN management.

An increased use of organic phosphorous based chemical pesticides in domestic and overseas agriculture has resultedin emergence of tolerant strains of insect pests. These pests have spread throughout South Korea and are responsible forsignificant reduction in crop yields. Furthermore, as yet there is no effective way of controlling these insects or the damageresulting from pest infestation. To this end, we are attempting to develop biological control based methods to protectcrop plants against insect pests. A screen for biocontrol agents conducted in five farms that were heavily infested bynematodes in 2015-2016 identified Aspergillus niger F22 strain that was very effective against root-knot nematode. Afour-time treatment with A. niger F22 at an internal of ten days was able to reduce nematode population by 70-90%compared to untreated controls. The biocontrol agent was also more effective compared to ograno-phosphorus based pesticide,which caused a 30% reduction in nematode population. Notably, the extract (suspension concentrate) prepared from A.niger culture was equally effective in controlling the root-knot nematode and is currently being developed as a marketableproduct under the brand name “NAMAFREE”.

식물 기생성 선충은 토양 병해의 중요한 요인 중 하나로 작물 생산에 심각한 피해를 일으키지만 토양 속에서 일어나므로 그 피해를 판단하기 어렵다. 식물 기생성 선충은 주로 오이나 당근, 상추 등 많은 작물의 뿌리를 통하여 침입하는데 이때 생긴 상처를 통하여 토양 전염 병원균의 감염이 발생되고 또한 바이러스도 전파하여 작물의 많은 수확 손실을 가져온다. 본 연구에서는 뿌리혹선충 방제를 위한 친환 경적인 방법을 찾고자 유기성 부산물의 퇴비 처리에 의한 상추의 뿌리혹선충 방제 효과와 상추 수확량, 토양 화학성분 및 미생물밀도를 분석하였다. 퇴비를 처리하지 않은 무처리구와 퇴비 처리량(3, 10kg/3.3m2) 별 효과를 비교한 결과, 퇴비 처리량의 증가에 따라 상추의 뿌리혹선충 발병이 유의성 있 게 감소하였으며(R2=0.230, p=0.022) 따라서 수확량은 증가하였다(R2=0.360, p=0.004). 상추 근권 토 양 중 방선균의 밀도도 퇴비 처리에 의하여 약 10배 정도 유의성 있게 증가하였으며(R2=0.276, p=0.013), 방선균 밀도와 수확량 간에 높은 정의 상관관계가 확인되었다(R2=0.232, p=0.021). 각 처리 구의 토양 성분을 분석 비교한 결과 퇴비를 처리한 토양에서 유기물 함량과 양이온 교환용량이 높게 나 타났다. 이러한 결과로 볼 때 충분히 완숙된 유기성 부산물 퇴비 처리는 상추의 뿌리혹선충의 발병율을 낮추고 좋은 미생물인 방선균 밀도를 증가시킴과 동시에 토양의 지력도 향상시켜 상추 생산량을 증가 시킬 수 있는 친환경적이고 효과적인 뿌리혹선충 방제법 임을 알 수 있었다.

Thrips worms and root-knot nematodes occur in a variety of crops, and have shown a great deal of damage to farm income every year, and the damage is increasing every year. In order to solve these problems, a variety of biological materials are used in Korea to develop a control agent. However, there are very few products available that can satisfy the consumer's satisfactory control effect, efficacy, formulation stability and pesticide compatibility. In order to propose a biological control solution to these problems, this study was conducted to develop the optimal bioprocess technology and formulations suitable for the material by transferring the Aspergillus nigerF22 strain, which is effective for root-knot nematodes, at Chonnam National University. This study was conducted to investigate the efficacy of Aspergillus niger F22 20% suspension concentrate (Productname:NEMAFREE), which has excellent efficacy on root nematodes. The packing test result showed about 70-90% control effect. Soil fumigation and disinfection treatments after 4 days of planting were effective. In addition, we have developed a product to control the under powder pupa using Beauveria bassiana ERL836, an insect pathogenic microorganism, which has excellent control effect against resistant insect pupa. The main purpose of this study was to investigate the effect of insect pests on the under poor control of the pupa in the soil. In the pavement test, more than 70%(GR) formulation, which can be treated withch emical pesticides, and it is confirmed that synergy effect is in the control of Thrips worm.

The BIG11003 strain was isolated as protein-degrading actinomycetes from cucumber farm. The effect of plant natural resources (Azadirachta indica L and Sophora angustifolia) of juveniles and the hatching of eggs of Meloidogyne sp. were examined the laboratory. The nematicides (fosthiazate), actinomycetes protease and S. angustifolia extract resulted in 45.6, 46.6 and 51.23% mortality of J2 of M. incognita. The nematicides (fosthiazate), A. indica L and S. angustifolia extract resulted in 2.06, 3.96 and 6.22% hatch of egg of M. incognita. Antinematode activity test had done after the formulation of liquid (Nemastar) with mixture of additives and inerts into selected highly active natural material and actinomycetes protease. In pot and field experiments, the nemastar had good control efficacy against plant root-knot nematodes. Anti-nematode activity of strain BIG11003 from phylogentic analysis based on 16S rDNA sequences, it is suggested the Streptomyces koyangensis.

RNAi 기법은 예쁜꼬마선충을 비롯하여 초파리, 생쥐, 인체및 식물들을 포함한 다양한 생물종에서 작용기작이 잘 알려져 있고, 특정 유전자들의 발현을 제어하기 위해 사용되어 왔다.본 논문은 RNAi 기법을 통해 구축된 뿌리혹선충 저항성 형질전환식물체들의 개발현황, 발전 및 응용 가능성에 대해 고찰하고자 하였다. 지난 10여년에 걸쳐 진행된 연구들을 통해 다양한 분화단계의 뿌리혹선충으로부터 분석된 79,978개의 EST가 GenBank에등록되었고, 고구마뿌리혹선충(M. incognita)과 당근뿌리혹선충(M. hapla)의 전체 게놈 염기서열이 해독됨으로써 뿌리혹선충의 기생에 관련된 단백질들 및 식물세포벽 분해 관련 효소들에 대한 정보를 이용할 수 있게 되었다. RNAi의 기본 기작은 모든 진핵생물종에서 잘 보존되어 있고, 최근 식물기생선충들에서 RNAi 효과에 대한 연구결과들이 많이 발표되었다. 서로 다른 뿌리혹선충들에서 현재까지 22종 이상의 RNAi를위한 목표 유전자들이 보고되었다. 제2령 식물기생선충(second-stage juvenile of plant parasitic nematodes)에게dsRNA의 섭취를 유도하는 octopamine, resorcinol, serotonin등의 화합물들이 발견되었고, 이를 이용하여 선충 유전자의 발현제어를 쉽게 판별할 수 있는 새로운 기술의 활용이 가능하게 되었다. 최근에 RNAi 기술의 응용 및 발전을 통해 형질전환식물체에서 발현된 dsRNA에 의한 식물기생선충 유전자들의 발현제어가 증명되었고, 이를 위한 핵심 요소들로서 적절한 선충 표적 유전자의 선택, 식물체 내 높은 함량의 dsRNA의 발현 및선충이 섭취할 수 있는 충분한 양의 dsRNA의 운반 등이 중요하다는 것이 밝혀졌다. 특히, 비표적 유전자서열(off-target gene sequence)의 발현제어를 피하기 위해 다음과 같은 사항들이 고려되어야 한다. 1)비표적 유전자서열을 확인할 수 있는 소프트웨어의 개발 및 이를 통한 비표적 유전자서열을 제거한 RNAi 벡터를 제작하여야 한다. 2)식물과 동물에서 상동성이 높은 표적 유전자의 발현을 피해야 한다. 3)전사해석틀(open reading frames)의 염기서열들 보다 상동성이 낮은 5' 혹은 3'-비해석부위(untranslated regions)로부터 표적 유전자를설계하여야 한다.

The nematicidal activity of Phellodendron amurense rhizome-derived materials (methanol extract) toward Meloidogyne Spp. second-stage juveniles (J2) and these effects on Cucumis sativus and Cucumis melo. Results were compared with these of fosthiazate. J2 was examined using 24-well plate tests, pot bioassays (C. sativa and C. melo) and Field trials (C. melo). In 24-well plate test with J2, methanol extract of P. amurense exhibited 98.7% and 69.8% mortality at 0.25 and 0.125 mg/ml toward J2, respectively, whereas Fosthiazate showed 100% mortality at 1 mg/ml. In pot bioassays with J2, P. amurense rhizome methanol extract gave 79.5% and 57.4% mortality at 2ℓ/m2(1,000x) and 2ℓ/m2(2,000x)/3kg soil from C. sativa and 73.7% and 53.3% mortality at 2ℓ/m2(1,000x) and 2ℓ/m2(2,000x)/3kg soil from C. melo, respectively. In Field test at C. melo in greenhouse showed 55.1% and 26.9% mortality at 2ℓ/m2(1,000x) and 2ℓ/m2(2,000x) applied soil. P. amurense rhizome-derived materials, merit further study as potential root-knot nematode control agents because of their nematicidal activity.

본 연구는 10년 이상 과채류를 재배하여 뿌리혹선충 피해가 많이 발생되었던 시설재배 토양에서 친환경적인 뿌리혹선충방제를 위하여 밀기울 토양환원처리 효과를 구명하였다. 토양소독처리후 뿌리혹선충의 밀도를 조사한 결과 시험전과 비교하여 모든 처리구에서 뿌리혹선충밀도가 감소하는 경향을 보였지만 특히 밀기울처리구에서는 높은 방제효과를 보였다. 처리후 90일경에도 밀기울처리구가 매우 낮게 유지되었으며 멜론의 생육도 가장 양호하였다. 수확기 멜론의 고사율을 조사한 결과 무처리구 65%인데 비해 밀기울처리구, 3%로 현저히 낮았으며 과실의 크기와 품질도 밀기울처리구가 우수하였다. 따라서 밀기울 토양환원처리는 뿌리혹선충 발생포장에 농약을 사용하지 않고 멜론을 1작기 동안 안전하게 재배할 수 있는 유망한 소독방법일 뿐만 아니라 멜론의 품질을 개선하는데 매우 효과적인 방법으로 생각되었다.

It is well known that the root-knot nematodes, Meloidogyne spp., incite and aggravate the diseases caused by fungal and bacterial pathogens. The synergistic effects of the inoculation of Meloidogyne incognita combined with Fusarium oxysporum f. sp. lycopersici showed the greatly increased wilt symptoms developed on tomato plants compared to the inoculation of either of the two pests alone. For the biological control of the complex disease, a variety of bacterial isolates were tested for antagonistic effects to select ones that had both nematicidal and antifungal activities. Among forty plant growth-promoting rhizobacteria (PGPR) tested, Paenibacillus polymyxa G508 and G462 and P. lentimorbus G158 showed strong antifungal and nematicidal activities against F. oxysporum f. sp. lycopersici and second-stage juveniles (J2) of M. incognita, respectively, and also inhibited egg hatch of the nematode. The addition of Paenibacillus strains into potted soil suppressed the Fusarium-wilt severity and root galling on tomato and increased plant growths. P. lentimorbus G158 were abundantly proliferated on tomato seeds and hypocotyls more than P. polymyxa G 462 and had no phytotoxic effect on tomato plant. Under the greenhouse conditions, seed treatment of P. lentimorbus G158 reduced wilt severity caused by Fusarium wilt-root knot disease complex and root gall formation and increased tomato growth compared to the untreated control. Root-galls caused by both pathogens treated with bacterial culture had fewer and smaller giant-cells than untreated control, and scanning electron microscopy revealed alteration and distortion of hyphal cell wall of F. oxysporum and lysis of M. incognita egg shell by the bacterial treatment. All of these results suggest the Paenibacillus strains, especially G158 may have a high potential developed as biological control agents for the complex disease.

This study was conducted to evaluate the effects of temperature and nematicides on endospore attachment characteristics of 2 Korean isolates of nematodeparasitic bacteria, Pasteuria penetrans. P. penetrans CJ-1 and 98-35 isolates and 3 species of root-knot nematodes in U. of Florida were used ; Meloidogyne incognita (MI), M. arenaria (MA), and M. javanica (MJ). Three nematicide levels of 2, 4, and 6 ppm were compared by treating Vydate and Nemacur in the endospore containing soils. The endospores were attached to the root-knot nematode juveniles by centrifugal method. Reproduction of the isolates was checked by observing root-knot nematode females harvested from inoculated tomato roots. 1. Among the two Korean isolates, 98-35 showed attachments to MI, MA, and MJ juveniles, but it could not reproduce in any species. CJ-1 reproduced on all the 3 tested root-knot nematode species. 2. Endospores pretreated in -14°C showed higher attachment rate than those pretreated in 4, 24, and 40℃. 3. Nemacur treatments significantly suppressed the attachment of the endospores to the juveniles, while Vydate treatment effects were negligible.

The toxicity of Kaempferia galanga rhizome materials and constituents against Meloidogyne incognita second‐stage juveniles (J2) and eggs were examined. The active principles of K. galanga rhizome were identified as the phenylpropanoids ethyl (E)‐cinnamate (EC, 1) and ethyl (E)‐p‐methoxycinnamate (EMC, 2) by spectroscopic analysis. Results were compared with those of carbofuran, fosthiazate, and metam‐sodium. In direct‐contact mortality bioassay, EC (LC50, 0.037 mg/ml) was the most toxic constituent, followed by EMC (0.041 mg/ml). EC was more effective than carbofuran (LC50, 0.092 mg/ml) but less active than fosthiazate (0.002 mg/ml). EC, egg hatch was inhibited 100, 93, and 87% at 125, 62.5, and 31.25 μg/ml, respectively. EMC caused 100, 81, and 75% inhibition of egg hatch at 125, 62.5, and 31.25 μg/ml, respectively. The inhibition of two phenylpropanoids were similar or more inhibition to that of either carbofuran or metam‐sodium but was lower than that of fosthiazate. In contact + fumigant mortality bioassay, EC and EMC treatments resulted in 86 and c 73% mortality at 0.5 and 0.125 mg/g soil, respectively. The lethality of these phenylpropanoids was almost similar to that of either carbofuran or metam‐sodium but was lower than that of fosthiazate. In vapor‐phase mortality bioassay, EC and EMC were more effective in closed container than open containers, indicating that the mode of delivery of these compounds was, in part, a result of vapor action. K. galanga rhizome‐derived materials, merit further study as potential nematicides and hatching inhibitors for the control of M. incognita populations.

The nematicidal activity of Kaempferia galanga rhizome-derived materials (methanol extract, steam distillate, and powder) toward M. incognita second-stage juveniles (J2) was examined using residual contact toxicity and pot bioassays. In residual contact toxicity bioassays with J2, the active principles of K. galanga rhizome were identified as the phenylpropanoids ethyl cinnamate (EC, 1) and ethyl-p-methoxycinnamate (EMC, 2) by spectroscopic analysis. EC exhibited 95% and 49% mortality at 0.06 and 0.04 mg/ml toward J2, respectively, whereas EMC showed 98% and 63% mortality at 0.1 and 0.08 mg/ml. In pot tests with J2, K. galanga rhizome methanol extract gave 92% and 82% mortality at 100 and 20 mg/50g soil, respectively. Steam distillate gave 88% and 68% mortality at 85 and 42.5 mg/50g soil, respectively, whereas rhizome powder provided 83% and 62% mortality at 400 and 200 mg/50g soil. K. galanga rhizome-derived materials, particularly EC and EMC, merit further study as potential root-knot nematode control agents or leads because of their great activity as a nematicide.