• 한국식물병리학회지
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• 제14권3호
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• pp.278-285
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• 1998

Effects of chitosan on growth of tomato plant, and suppression of Fusaruim wilt caused by Fusarium oxysporum f. sp. lycopersici and late blight casued by Phytophthora infestans, were examined. Both late blight and fusarium wilt were suppressed by spray and irrigation of chitosan, respectively. Inhibition of mycelial growth was not greatly affected by molecular size of chitosan but, concentration dependent effects was observed. Ninty percent of P. infestans and 80% of F. oxysporum f. sp. lycopersici of mycelial growth was inhibited by 1,000 ppm of chitosan (MW 30,000~50,000) when amended in plate media. Induction of defense-related gene expression in plant by chitosan treatments were observed when chitosan treated tobacco and tomato RNA samples were hybridized with several defense-related genes as probes. The results revealed that $\beta$-1,3-glucanase and chitinase genes were strongly induced, while pathogenesis-related protein-1, 3-hydroxy-3-methylglutaryl coenzyme A reductase, anionic peroxidase, phenylalanine ammonia lyase genes were weakly induced by chitosan treatment. These results suggest that chitosan have dual effects on these host-pathogen interactions. Possible roles of chitosan in suppression of tomato diseases by inhibition of mycelial growth and activation of plant defense responses are discussed.

• The Plant Pathology Journal
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• 제28권2호
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• pp.185-190
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• 2012

Sclerotinia sclerotiorum is a serious pathogen which causes yield loss in many dicotyledonous crops including potato. The objective of this study was to assess the potential of biofumigation using three Brassica crops including Brassica napus, B. juncea and B. campestris against potato stem rot caused by S. sclerotiorum by in vitro tests. Both macerated and irradiated dried tissues were able to reduce radial growth and sclerotia formation of five pathogen isolates on PDA, but macerated live tissues were more effective. Compared with other tested crops, B. juncea showed more inhibitory effect against the pathogen. The volatile compounds produced from macerated tissues were identified using a gas chromatograph-mass spectrometer. The main identified compounds were methyl, allyl and butyl isothiocyanates. Different concentrations of these compounds inhibited mycelial growth of the pathogen in vitro when applied as the vapor of pure chemicals. A negative relationship was observed between chemicals concentrations and growth inhibition percentage. In this study, it became clear that the tissues of local Brassica crops release glucosinolates and have a good potential to be used against the pathogen in field examinations.

• Weed & Turfgrass Science
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• 제6권2호
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• pp.151-156
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• 2017

국내 Kentucky bluegrass로 조성된 골프장이나 잔디 재배지에서 여름철에 여름잎마름병 발생으로 인한 피해가 심각한 상황이다. 그럼에도 불구하고 여름잎마름병방제약제가 아직까지 등록되어있지 않아 병원균에 효과적인 약제를 선발하기 위하여 본 연구를 수행하였다. 전형적인 여름잎마름병 병징에서 병원균을 분리하였고 ITS1과 ITS4 염기서열 분석으로 Magnaporthiopsis poae로 동정되었다. 잔디용으로 사용되는 10개의 약제를 대상으로 병원균 반응을 조사한 결과, 약제의 농도가 높아질수록 병원균 생장을 억제하였고 시간이 경과할수록 병원균 억제효과가 떨어지는 것이 관찰되었다. triazole계 약제 4종(metconazole, myclobutanil, propiconazole과 tebuconazole)의 병원균 억제효과는 100%로 나타났다. 다음으로 thiophanate-methyl의 억제효과가 높았으며 strobilurin계의 약제인 azoxystrobin, pyraclostrobin과 trifloxystrobin 약제를 비교하였을 때는 pyraclostrobin 약제가 가장 높게 나타났으며 다음으로 azoxystrobin과 trifloxystrobin 순으로 나타났다. Fludioxonil과 fluxapyroxad의 병원균 억제효과는 trifloxystrobin과 유사하게 나타났다.

• International Journal of Industrial Entomology and Biomaterials
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• 제14권2호
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• pp.75-80
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• 2007

Ethanolic extracts of twenty-one plant species were tested in vitro for their fungitoxic properties against leaf spot causing pathogen of mulberry Myrothecium roridum by poisoned food technique. Ethanolic extracts of twenty-plant spp. reduced mycelial growth of M. roridum significantly except E. pulcherrima. Highest inhibition of M. roridum colony growth observed in 10% extracts of E. citriodora (49.45%) followed by D. metel (39.45%), Chromolaena odoratum (25.56%) and A. sativum (25.00%). Among the concentration tested, 10% concentration was found significantly higher effective on reducing colony growth followed by 5 and 2.5%. Aqueous extract fresh leaves/bulb of seven short-listed plant spp. (inhibition>15% in ethanolic extracts) revealed that D. metel inhibited (23.43%) followed by E. citriodora (14.66%), C. odoratum (13.53%). On dry leaf extracts D. metel was found more effective than E. citriodora. The results indicated that D. metel, E. citriodora, C. odoratum and A. sativum having high fungitoxicity against M. roridum and ethanolic extract found more effective than aqueous extract.

• 한국유기농업학회지
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• 제12권1호
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• pp.101-114
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• 2004

This study was carried out to clarify the effects of antagonistic microorganism, Bacillus sp. JC181 isolated from the greenhouse soil grown cucumber plants on the growth inhibition of plant pathogen, fusarium wilt (Fusarium oxysporum) occurred in cucumber plants in greenhouse. Antagonistic bacterial strains were isolated and were investigated into the antifungal activity of the antagonistic microorganism against fusarium wilt. Screened fourteen bacterial strains which strongly inhibited F. oxysporum were isolated from thc greenhouse soil grown cucumber plants, and the best antagonistic bacterial strain designated as JC181, was finally selected. Antagonistic bacterial strain JC181 was identified to be the genus Bacillus sp. based on the morphological and biochemical characterization. Bacillus sp. JC181 showed 58.2% of antifungal activity against the plant pathogen growth of F. oxysporum. By the bacterialization of culture broth and heated filtrates of culture broth, Bacterial strain, Bacillus sp. JC181. showed 91.2% and 260% of antifungal activity against F. oxysporum, respectivrly.

• Mycobiology
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• 제30권3호
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• pp.175-179
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• 2002

A study on comparative efficacy and in vitro activity of fresh cow urine and cow dung for controlling Sclerotinia rot caused by Sclerotinia sclerotiorum of cucumber was carried out following mycelial growth inhibition test, treated and untreated sclerotia with these organic matters at different days of incubation. Results showed that cow urine suppressed more effectively the mycelial growth even after 5 days of incubation in comparison to cow dung. The highest inhibition 75.9% of mycelial growth was recorded in cow dung potato dextrose agar(CUPDA) after 3 days of incubation and least 22.7% was in cow dung potato dextrose agar(CUPDA) after same days of incubation. Mycelial growth from sclerotia of S. sclerotiorum was also influenced by PDA medium mixed with cow urine and cow dung. After 6 days of incubation in CUPDA mycelial growth was only 12.9 mm whereas in CDPDA and PDA the corresponding growth at the same time were 65.8 mm and 80.0 mm. Treated sclerotia of the selected fungus with cow urine had a very effective role on suppression of mycelial growth than that of untreated one. No mycelial growth was observed up to 4 days in treated sclerotia with cow urine. After 5 days only 0.9 mm mycelial growth was measured in treated sclerotia, while in case of untreated sclerotia the growth was 42.6 mm. Application of cow urine and cow dung on growing plants inoculated with the pathogen at different concentrations also proved their inhibitive effects.

• The Plant Pathology Journal
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• 제26권4호
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• pp.340-345
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• 2010

Two similar microbial fungicides (termed as MA and MB) developed in a Korean biopesticide company were analyzed and compared each other in their biocontrol activities against the phytophthora blight of chili pepper caused by Phytophthora capsici. MA and MB contained the microbe Paenibacillus polymyxa and Bacillus subtilis, respectively, with concentrations over those posted on the microbial products. In comparison of the isolated microbes (termed as MAP from MA and MBB from MB) in the antagonistic activities against P. capsici was effective, prominently against zoospore germination, while MBB only significantly inhibited the mycelia growth of the pathogen. Some effectiveness of MAP and MBB was noted in the inhibition of zoosporangium formation and zoospore release from zoosporangia; however, no such large difference between MAP and MBB was noted. In a pot experiment, MA reduced the severity of the phytophthora blight more than MB, suggesting that the disease control efficacy would be more attributable to the inhibition of zoospore germination than mycelia growth of P. capsici. These results also suggest that the similar microbes MA and MB targeting different points in the life cycle of the pathogen differ in the disease control efficacies. Therefore, to develop microbial fungicides it is required to examine the targeting points in the pathogen's life cycle as well as the action mode of antagonistic microorganisms.

• 식물병연구
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• 제16권3호
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• pp.266-273
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• 2010

Xanthomonas axonopodis pv. glycines에 의해 발병되는 콩 불마름병은 콩에 가장 많이 발생하는 중요한 세균성 병해 중 하나이다. 게다가 병원균은 강한 병원성을 가지고 한국 전역에 분포하고 있지만, 한국에서는 불마름병방제를 위한 약제나 저항성 품종이 개발되어 있지 못한 실정이다. 따라서 본 연구의 목적은 불마름병을 화학적 방법으로 방제할 수 있는 방법을 개발하기 위해 수행되었다. 콩 불마름병 병원균의 효과적인 생육억제 약제를 선발하기 위해 여러 가지 살세균제들(8개의 항생제, 2개의 구리화합물, 1개의 quinoline, 18개의 농약)을 이용하여 효과를 확인하였다. 실내 생장억제 효과조사 결과, tetracycline, streptomycin sulfate 처리에서 병원균의 생육이 크게 억제되었으며, 또한 oxolinic acid도 병원균의 생육억제 효과가 우수하였다. 하지만 vancomycin, polymyxin B sulfate and copper compounds 등은 불마름병 병원균의 생육억제효과가 확인되지 않았다. 18종의 농용약제 중에는 streptomycin sulfate + oxytetracycline(18.8 + 1.5%)WP, oxytetracycline(17%)WP, oxolinic acid(20%) 등이 실내에서 병원균의 생육억제 효과가 높은 것으로 조사되었다. 선발된 5종의 농용약제에 대하여 포장에서 방제효과 시험을 실시한 결과, streptomycin sulfate + oxytetracycline (18.8 + 1.5%) WP와 oxytetracycline(17%) WP가 자연 감염된 태광콩 포장에서 70% 이상의 높은 방제효과를 나타내었다. 그러므로 콩불마름병균에 대한 강한 억제효과를 가지는 이 약제들은 콩 불마름병의 화학적 방제에 실용성이 있을 것으로 생각된다.

• International Journal of Industrial Entomology and Biomaterials
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• 제5권2호
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• pp.183-188
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• 2002

Anti-fungal potential of 5 plant extracts viz., Eucalyptus citriodora, Allium sativum, Cassia sophera, Chromolaena odorata and Datura metel on the growth of mulberry brown leaf spot pathogen Myrothecium roridum were examined. Except fur the aqueous extract of Allium bulb, ethanolic leaf extract of all other plants more efficiently reduced the colony growth of the fungus on potato-dextrose-agar, Of which, Allium and Eucalyptus extracts were more effective. Initiation of radial growth of M. roridum on solid media was deferred maximum 6 days by ethanolic Eucalyptus extract and 4 days by aqueous Allium extract at $0.4 mg.ml^{-1}$. In the liquid media amended with Eucalyptus extract ($0.4 mg.ml^{-1}$) complete inhibition of sporulation was noticed upto 8 days, and initial inhibition of mycelial bio-mass generation was considerably diminished with time and reduction was 1.3 fold 14 days after application. While, complete inhibition of mycelial growth for 6-14 days was recorded with $\geq$0.1 mg.ml$^{-1}$ commercial eucalyptus oil. However, rejuvenation of growth appeared when fungus was re-inoculated in fresh media. Post-inoculate application of different doses Of Eucalyptus and Allium extracts significantly (p < 0.05) reduced the disease severity in pot-ted mulberry. However, persistence of the effect up to 28 days was apparent at $\geq$ 1.0 mg.ml$^{-1}$ and effectively was on par with carbendazim (1 mg.ml$^{-1}$ ). Almost equal control ability of 1.0 mg.ml$^{-1}$ Eucalyptus extracts can be achieved by ca. 10 times lowered dose of commercial eucalyptus oil. It seems, the toxic principle of E. citrodora to M. roridum is fungistatic in nature and may have essential oil based origin.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.386-389
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• 2002

식물의 토양전염병을 유발하는 P. aphanidermatum 및 R. solani에 대한 길항력, 생장속도 및 표면장력 감소를 고려한 RPI (relative performance indices) 기법을 이용하여 90 여개 후보균 중 #16 길항균을 선정하였다. 선정된 Bacillus sp. #16은 16S rRNA 서열을 분석한 후 GenBank에서 비교한 결과 B. subtilis DSM10과 99% 유사성을 보였다. 또한 pot test 결과 오이 모잘록병에 대해 우수한 방제가를 보였다.