• Mycobiology
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• 제30권2호
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• pp.96-101
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• 2002

Four pathogenic fungal isolates belonging to different genera including Alternaria, Fusarium and Curvularia were isolated from selected diseased weeds growing in the fields in Dakahalia district. The inoculum of these pathogenic fungi specific to weeds were cultured, standardized and formulated as alginate pellets containing mycelium plus culture filtrate. These mycoherbicides were evaluated for disease severity(DS). Maximum DS was obtained with the alginate pellets of mycelium filtrate Fusarium solani. Physiological changes of the treated weed were determined 5 aiid 10 days after treatments. As compared to the healthy weeds, all mycoherbicide formulations significantly decreased the amount of photosynthetic pigments and subsequently soluble and insoluble sugars in the infected weeds. The mycoherbicide formulation of F. solani had the greatest effect on lowering to the abovementioned amount in the leaves of Chenopodium murale. Generally, treatment of weed leaves with the specific mycoherbicide led to a highly significant increase in total phenol content when compared to the healthy control weed. C. murale infected with the mycoherbicide formulation of F. solani had higher levels of phenolic compounds than those other treated weeds particularly after 10 days of inoculation.

• 한국식물병리학회지
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• 제14권4호
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• pp.358-360
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• 1998

An anthracnose of Rumex crispus was endemic in wet area around a fruit garden of Taejon in Korea. A fungal pathogen was repeatedly isolated from the leaf spot lesions of the weed plant and identified as Colletotrichum gloeosporioides. The plant was controlled completely by fungal inoculation with 5$\times$105 conidia/ml. The fungus has potential to be developed as a mycoherbicide for weed control.

• The Plant Pathology Journal
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• 제18권2호
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• pp.81-84
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• 2002

Effects of temperature and dew period on sporulation of a mycoherbicide, Epicoccosorus nematosporus, on the lesion of its host, Eleocharis kuroguwai were determined. Conidia formation was first observed after 10 days on plants incubated for either 12 or 16 h in a dew chamber at 28$^{\circ}C$; 16 h dew period resulted in more conidia formation. As the dew period was decreased to less than 8 h, fewer conidia formed. Conidial production was most abundant at 28$^{\circ}C$ and produced as much as 3.3$\times$10$^4$conidia per lesion, while 0.1$\times$10$^3$and 2.3$\times$10$^3$conidia per lesion were produced at 16$^{\circ}C$ and 36$^{\circ}C$, respectively. Alternating temperature regimes, i.e., 30/15, 30/20, 28/20, and 28/15$^{\circ}C$ (day/night) were much better than constant temperature, i.e., 30/30, 28/28/, and 20/2$0^{\circ}C$ for sporulation. In the second sporulation, there were as much as 3.1$\times$10$^4$conidia per lesion (ca. <50% of the first sporulation). Then, sporulation dropped sharply to 6.2$\times$10$^2$conidia per lesion in the third sporulation. Results of this study suggest that temperature combined with dew period is the primary limiting factor in the use of E. nematosporus as a mycoherbicide off, kuroguwai.

• 한국식물병리학회지
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• 제10권1호
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• pp.61-63
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• 1994

A brown leaf and stem spot disease of bayonet-grass (Scirpus maritimus) was epidemic in reclaimed paddy fields of Chunbuk province, Korea. A fungal pathogen was repeatedly isolated from the necrotic lesions of the bayonet-grass and identified as Nimbya scirpicola. The pathogen induced disease symptoms only in bayonet-grass but not in 8 other plants tested; Brassica pathogen induced disease symptoms only in bayonet-grass but not in 8 other plants tested; Brassica compestris subsp. napus var. pekinensis, Cucumis sativus, Glycine max, Hordeum vulgare, Lycopersicon esculentum, Oryza sativa, Sesamum indicum and Triticum aestivum. The fungus has potential to be developed as a mycoherbicide.

• 아시안잔디학회지
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• 제20권2호
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• pp.175-190
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• 2006

미생물제재(mycoherbicide)라는 용어는 1970년대부터 사용되기 시작하였다. 하지만 미생물 제재에 대한 관심은 화학제재의 비용증가로 인해 최근 주목을 받게 되었다. 고전적인 생물학적방제재(Biological Control Agent, BCA)는 생태적으로 안전하다는 이유로 생태학적인 관점에서 관심을 끌고 있다. 반면, 현대적인 의미의 생물학적방제재는 인공적으로 배양이 가능하고, 또한 그 잡초방제 효과도 화학제초제와 같은 수준이 요구된다. 현재 미생물제재는 7개국에서 곰팡이로부터 만들어지는 26종이있다. 이들은 재배작물에는 안전한 기주특이성을 갖는다. 그러나 대부분의 약제전달체계는 살아있는 미생물을 활력을 유지한 상태로 장기간 보존할 수 있는 능력을 가지고 있어야 함에도 불구하고 대부분이 조건을 충족시키질 못하였다. 또한, 실험실 수준에서는 방제효과가 잘 나타나지만, 실무적으로 사용할 경우 사용년도 및 포장에 따라 방제효과의 발현성과 지속성이 다르게 나타났다. 이 밖에 미생물제재 사용시 습도, 이슬, 온도 및 이들 요인이 잡초방제에 미치는 효과에 대한 연구결과도 미비한 상태이다. 따라서 잡초방제효과가 뛰어난 미 생물제재를 선별해야한다. 선행된 연구에서 제안된 효과적인 미생물제재의 조건은 첫째, 인공 배양법으로 내구성이 있는 접종원(inoculum)의 대량 생산이 가능하고, 둘째, 유전적으로 안정하면서 기주 특이성이 있고, 셋째, 다양한 범위의 잡초방제효과 있어야 한다. 미생물제재의 생산과 보급은 잡초의 생물학적인 방제에 지대한 역할을 할 수 있다. 액상보다는 입상 형태의 미생물제재가 가벼워서 사용이 간편하며, 젤(gel) 타입의 미생물제재도 사용되는 것으로 알려져 있다.

• The Plant Pathology Journal
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• 제17권6호
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• pp.363.1-363
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• 2001

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.107.1-107
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• 2003

The fermentation process and subsequent processing determine the efficacy of a bioherbicide propagule. Large batches of biomass of the mycoherbicide agent for white clover, Sclerotium sp.(BWC98-105) was produced in simple liquid fermentator in 5 gallons vessels(Model No. 8087, Dabo Inc., Korea) with oxygen supply(DPH16000, FineTech Inc., Korea) simulating industrial conditions by utilizing commercially available, inexpensive ingredients (10 ％ rice bran), The maximum biomass yield of Sclerotium sp.(BWC98-105) was obtained after 5 days of air pumped incubation at room temperature condition(22-28$^{\circ}C$). By using this simple facility, it could get fragmented or proliferated greatly and attained maximum mycelia biomass. The biomass of mycoherbicide agent consisted of hyphae devoid of spores. Biomass mycelia of the fungus 99％ survival at room temperature after 2 me. A thorough understanding of the effects of fermentation and formulation on viability and virulence is required to guide these processes. After an economical yield level of bioherbicide propagule has been achieved in a fermentation process, formulation becomes a critical factor which influences product efficacy. Because the fermentation must be stopped at a point when virulence/viability are optimum, the live bioherbicide propagule must be stabilized, formulated, and packaged.

• The Plant Pathology Journal
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• 제18권1호
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• pp.50-53
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• 2002

To develop Epicoccosorus nematosporus as a mycoherbicide of Eleocharis kuroguwai, the optimum temperature and humidity for sporulation of the pathogen were studied. Conidial production was most abundant at $28^{\circ}C$ with RH 60%, which yielded 661 mg in 9 cm Petri dish. Light intensity of 3,000 up to 7,500 lux was effective in stimulating conidial production of E. nematosporus on oatmeal agar, Light intensity affected sporulation more significantly than temperature. In the pot test, at least 12 h of dew period at $20^{\circ}C$ and $25^{\circ}C$ was required to achieve satisfactory conidial germination and appressorial formation. Few were killed at 8 h of dew period regardless of temperature. Sixteen hours of a single dew treatment immediately after inoculation killed more plants than did two or three repetitive dew treatments of 8-12 h.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.111-111
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• 2003

Several fungal isolates were isolated from diseased monochoria(Monochoria vaginalis, weed of paddy field), which has an resistance to sulfonyl urea(S.U.) herbicide, and were evaluated in the laboratory and greenhouse as potential mycoherbicide. Eight fungi, Alternaria sp., Colletotrichum sp., Curvularia sp., Paenicillium sp and etc. were observed in the isolates. Pathogenicity testing were done on the monochorias in the greenhouse. Monochorias were inoculated with suspensions containing conidia of each isolate at the rates of 1.0 ${\times}$ 10$\^$5/ conidia/ml and 0.1％ Tween 80 with hand-gun sprayer. Curvularia sp. and an unidentified fungal isolate caused 90-95％ mortality on the monochorias 15∼20 days after inoculation. However the other isolates induced slight symptom of disease on the monochorias. In the early stage of disease development sun-burn appearance was shown at the infected site and the last infected leaves and stems were withered to death. Subsequently the pathogenicity on the rice was evaluated with above two effective isolates. From the test an unidentified isolate showed pathogenicity on the rice but Curvularia sp., named as DBB2003, didn't. Now the mass production and formulation using Curvularia sp. DBB2003 are in progress and the field test will be followed. Combination product with Curvularia sp. DBB2003 and chemical herbicide will be more effect to control the monochoria resisted on S.U. herbicide and need to be further tested.

• The Plant Pathology Journal
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• 제20권1호
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• pp.52-57
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• 2004

Sclerotinia sp. (isolate BWC98-105) causes stem blight and root rot in Leghum sp., and is presently being evaluated as a potential mycoherbicide for the control of Trifoliorium repens. Bioassays have shown that Sclerotinia sp. produces phytotoxic substance which is biologically active against T. repens. Two biologically active compounds, designated as compoundsI and II, were produced in vitro from the culture filtrate of BWC98-105 isolate Sclerotium sp. Compounds I and II were purified by means of liquid-liquid extraction and $C_{18}$ open column chromatography (300 ${\times}$ 30 mm, i.d). To determine the purity, the purified compounds were analyzed by RP-HPLC. The analytical RP-HPLC column was a TOSOH ODS-120T (150 ${\times}$ 4.6 mm i.d, Japan), of which the flow rate was set at 0.7 mL/min using the linear gradient solvent system initiated with 15 % methanol to 85 % methanol for 50 min with monitoring at 254 nm. Under these RP-HPLC conditions, compounds I and II eluted at 3.49 and 4.13 min, respectively. Compound II was found to be most potent and host specific. However, compound I had a unique antibiotic activity against phytopathogenic bacteria like bacterial leaf blight (Xanthomonas oryzae) on rice, where it played a less important role in producing toxicity on T. repens. No toxin activity was detected in the water fraction after partitioning with several organic solvents. However, toxin activity was detected in the ethyl acetate and butanol fractions. In the leaf bioassay using compound II, the disease first appeared within 4-5 h as water soaked rot, which subsequently developed into well-defined blight affecting the whole plant.