• The Plant Pathology Journal
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• 제18권3호
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• pp.156-160
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• 2002

Cymbidium orchids with blight and rot symptoms were collected, and a total of 63 isolates of Fusarium app. was obtained from pseudobulbs, roots, and leaves of the diseased plants. The isolates were identified based on their morphological characteristics. Out of the 63 isolates of Fusatium sup., 51 isolates were identified as F. oxysporum, 10 isolates as F. solani, and the rest as F. proliferatum. F. oxysporum was isolated from all the Cymbidium spp., while F. solani and F. proliferatum were isolated only from Cymbidium ensifolium and C. ginatum, respectively. Isolates of the three Fusarium spp. were tested for pathogenicity to their hosts by artificial inoculation. The strongly pathogenic isolates of Fusarium spp. induced severe dry rot of pseudobulbs and roots of the host plants. The symptoms progressed up to the basal part of the leaves, which later caused blight of the entire plant. The dry root symptoms induced on the plants by artificial inoculation with the isolates of Fusarium app. were similar to those observed in the growers'greenhouses. This is the first report of dry rot of Cymbidium spp. caused by F. oxysporum, F. solani, and F. proliferatum in Korea.

• 생물환경조절학회지
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• 제32권2호
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• pp.165-171
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• 2023

감자 마른썩음병은 Fusarium 종에 의해 발병하는 감자 저장병 중 하나이며 저장중 수확후 손실을 일으키는 대표적인 병리장해이다. 맹아억제를 위해 허용된 chlorpropham 처리는 주로 가공용 감자의 상온저장 시 이용되고 있다. 본 연구에서는 감자 저장 중 맹아의 출현을 억제하기 위해 사용되는 chlorpropham 처리가 Fusarium에 의한 마른썩음병(Fusarium solani Appel & Wollenw) 발생의 억제 효과가 있는지 확인하기 위해 감자 '단오' 품종을 이용하여 수행되었다. 마른썩음병균의 균사 생장률을 조사하기 위해균사 생장은 F. oxysporum 균사를 치상한 chlorpropham(5.0, 50.4, 503.8, 5,038ppm)과 prochloraz(0.1, 1.0, 10.0, 100.0ppm) 약제배지를 이용하여 in vitro에서 조사하였다. 20℃에서 14일간 치상한 균사는 chlorpropham과 prochloraz 처리 시 처리 농도가 높을수록 생장이 더욱 억제되었으며, 억제율은 chlorpropham 503.8ppm과 prochloraz 10ppm 처리 시 각각98.2%와 100%를 나타냈다. 20℃ 상온과 4℃ 저온저장 중 마른썩음병 방제 효과는 F. oxysporum을 접종한 감자 괴경을 chlorpropham(5.0, 50.4, 503.8ppm)과 prochloraz(100ppm)에 침지처리하여 조사하였다. 상온 저장한 감자(20℃)의 병반 직경은 저장 70일 때에 무처리구 괴경의 13.7mm에 비해 chlorpropham 50.4ppm 처리구에서만10.7mm로 유의성이 있게 억제되었다. 저온에서는 모든 처리구에서 병반 진행은 통계적 유의차가 없이 유사하였다. 본 연구 결과에서 저장 감자의 마른썩음병을 억제하기 위해서는 수확 후 chlorpropham 50.4ppm 처리가 유용할 것으로 판단된다.

• 식물병연구
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• 제7권1호
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• pp.56-59
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• 2001

Stem rot of cacti was found at major cultivating areas including Koyang, Ansung and Eumsung of Korea in 2000. Bipolaris cactivora was consistently isolated from the lesions. The disease occurred on different species of cactus including Cereus peruvianus, C. neopithahaja f. monstruo년, C. tetragonus, Chamaeceresu silestrii, Ch. silvestrii, f. variegata, Gymnocalcium mihanovichii var. friedrichii. G. denudatum var. pentacantha, Hylocereus trigonus and Isolatocereus dumortier. Major symptoms on the cactus species except H. trigohus were almost identical. A rapid rot of the upper portion of the catus stem appeared, and became blackened and somewhat dry. On H. trigonus, the symptom was initially light yellow, water-soaked lesion, turned into light brown and dried to death. According to pathogenicity test, 10 out of 16 cactus species and varieties tested produced identical symptoms as found in the field. However, the fungi did not show pathogenicity to Notocactus scopa, Echinocactus grusonii, Eriocactus leninghausii, Lobivia nealeana, Mammillaria elongata var. intertexta.

• 한국균학회지
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• 제8권1호
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• pp.53-57
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• 1980

An undescribed black root rot of soybean, caused by Cylindrocladium crotalariae, was observed in Suweon area. The diseased plants showed yellowing at the top and dry rot at the root. Lesions of roots and stems in the soil were red to brown and main roots were cracked. Although not observed the disease in the field, leaves of inoculated test plants in the greenhouse exhibited circular, brown lesion surrounded by chloratic halos. The fungus was recovered in culture from the infected stem and root, and the perithecia of Calonectria crotalariae were demonstrated to be present as well as the cylindrocladium state. The fungus was pathogenic to the root, stem, petioles and leaves of soybean. The probable source of primary inoculum was microsclerotia formed in infected soybean root and stem from the previous season's soybean debris. Black root rot by this fungus was considered to be one of detrimental factors to the maximum yield of soybean. From the morphological and physiological characteristics and pathogenic behaviors, this fungus was identified as Cylindrocladium(Calonectria) crotalariae.

• 한국자원식물학회지
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• 제19권3호
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• pp.392-396
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• 2006

This study was conducted to evaluate the control effect of fungicides of sclerotinia rot control, growth characteristics, and seed yield in the cultivation of rapeseed. All fungicides treated had no effect on the growth of rapeseed. The major fungicides were mancozeb 75% WP, chlorothalonil 75% WP, dithianon 43% WP. difenoconazole 10% WP, benomyl 50% WP, and propineb 70% WP. Dry seed yield and control were increased largely with chlorothalonil 75% WP ($33g/12{\ell}$), fungicide than the other fungicides Sclerotinia rot. All fungicides had no injury with standard dosage. On the other hand all fungicides had slight injury in the double dosage level for the rapeseed.

• Mycobiology
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• 제30권4호
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• pp.233-239
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• 2002

The main aim of this study is to evaluate the efficiency of two biologically active compounds(Strom and F-760) in control of wheat root rot disease and its causal organisms. Fusarium graminearum, F. oxysporum, F. solani and Bipolaris sorokiniana were used as target organisms. In vitro, the two compounds showed fungicidal effect on all investigated pathogens resulted in suppression of radial growth and mycelial dry weight of them. Under greenhouse conditions, treatment of wheat grains with either Strom or F-760 before cultivation significantly reduced the percent of disease distribution as well as the mean disease rating of plants in both seedling and flowering stages. Fresh and dry weights of plants as well as water maintenance capacity were increased as the result of applying these compounds as seed dressing. Also data showed that the membrane stability of plants was injured as a result of infection with all investigated organisms, while this injury was alleviated when F-760 and Strom were applied. The $K^+$ efflux and the leakage of UV absorbing metabolites was stimulated with fungal infection. However, F-760 and Storm treatment partially retarded the stimulatory effect on leakage of $K^+$ and UV-absorbing metabolites of fungal infected plants. On the other side, the fungal infection had inhibitory effects on pigment fractions(chlorophyll a, b, and carotenoids) biosynthesis in wheat leaves. This retarding effect was partially or completely alleviated as the grains were treated with the applied compounds.

• 미생물학회지
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• 제1권1호
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• pp.45-47
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• 1963

1. A Kind of Bacillus, which was seemed to be pathogenic, was isolated from Pinus rigida planting. 2. The bacillus were grown well on the Agar-Bacto-Beef media (pH 7.4) at $30^{\circ}C$. C for 24 hours. 3. The soil infection for the one year old seedling was the best inoculating method in this experiment. 4. Almost of all characteristics were simillar between isolated and reisolated bacillus. 5. The author should like to call temporarily the name of this bacterial disease Stem-rot of pinus rigida Mill.

• Mycobiology
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• 제38권4호
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• pp.286-294
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• 2010

Epicoccum purpurascens stain 5615 AUMC was investigated for its biocontrol activity against root rot disease caused by Pythium irregulare. E. purpurascens greenhouse pathogenicity tests using three leguminous plants indicated that the fungus was nonpathogenic under the test conditions. The germination rate of the three species of legume seeds treated with a E. purpurascens homogenate increased significantly compared with the seeds infested with P. irregulare. No root rot symptoms were observed on seeds treated with E. purpurascens, and seedlings appeared more vigorous when compared with the non-treated control. A significant increase in seedling growth parameters (seedling length and fresh and dry weights) was observed in seedlings treated with E. purpurascens compared to pathogen-treated seedlings. Pre-treating the seeds with the bioagent fungus was more efficient for protecting seeds against the root rot disease caused by P. irregulare than waiting for disease dispersal before intervention. To determine whether E. purpurascens produced known anti-fungal compounds, an acetone extract of the fungus was analyzed by gas chromatography mass spectrometry. The extract revealed a high percentage of the cinnamic acid derivative (trimethylsiloxy) cinnamic acid methyl ester. The E. purpurascens isolate grew more rapidly than the P. irregulare pathogen in a dual culture on potato dextrose agar nutrient medium, although the two fungi grew similarly when cultured separately. This result may indicate antagonism via antibiosis or competition.

• The Plant Pathology Journal
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• 제32권1호
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• pp.1-7
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• 2016

Responses of Botryosphaeria dothidea to interrupted wetness periods were investigated under in vivo and in vitro conditions. Conidia of B. dothidea were allowed to germinate on apple fruits under wetting condition at $25^{\circ}C$ for 5 hr. They were air-dried for 0, 1, 2 or 4 hr, and then rewetted at $25^{\circ}C$ for 5 hr. Following an initial wetness period of 5 hr, 83% of the conidia germinated. The percent conidial germination increased to 96% when wetting was extended continuously another 5 hr. However, no further conidial germination was observed when wetting was interrupted by dry periods of 1, 2 and 4 hr, resulting in 83, 81 and 82%, respectively. The mean length of the germ tubes was $37{\mu}m$ after 5 hr of wetting and elongated to $157{\mu}m$ after 10 hr of continuous wetting. On the other hand, interruption of wetting by a dry period of 1 hr or longer after the 5 hr of initial wetting arrested the germ tube elongation at approximately $42{\mu}m$ long. Prolonged rewetting up to 40 hr did not restore germ tube elongation on slide glasses under substrate treatments. Model simulation using weather data sets revealed that ending infection periods by a dry period of at least 1 hr decreased the daily infection periods, avoiding the overestimation of infection warning. This information can be incorporated into infection models for scheduling fungicide sprays to control apple white rot with fewer fungicide applications.

• The Plant Pathology Journal
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• 제35권1호
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• pp.77-83
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• 2019

Chlorine dioxide ($ClO_2$) can be used as an alternative disinfectant for controlling fungal contamination during postharvest storage. In this study, we tested the in vitro and in vivo inhibitory effects of gaseous $ClO_2$ against Diaporthe batatas SP-d1, the causal agent of sweetpotato dry rot. In in vitro tests, spore suspensions of SP-d1 spread on acidified potato dextrose agar were treated with various $ClO_2$ concentrations (1-20 ppm) for 0-60 min. Fungal growth was significantly inhibited at 1 ppm of $ClO_2$ treatment for 30 min, and completely inhibited at 20 ppm. In in vivo tests, spore suspensions were drop-inoculated onto sweetpotato slices, followed by $ClO_2$ treatment with different concentrations and durations. Lesion diameters were not significantly different between the tested $ClO_2$ concentrations; however, lesion diameters significantly decreased upon increasing the exposure time. Similarly, fungal populations decreased at the tested $ClO_2$ concentrations over time. However, the sliced tissue itself hardened after 60-min $ClO_2$ treatments, especially at 20 ppm of $ClO_2$. When sweetpotato roots were dip-inoculated in spore suspensions for 10 min prior to treatment with 20 and 40 ppm of $ClO_2$ for 0-60 min, fungal populations decreased with increasing $ClO_2$ concentrations. Taken together, these results showed that gaseous $ClO_2$ could significantly inhibit D. batatas growth and dry rot development in sweetpotato. Overall, gaseous $ClO_2$ could be used to control this fungal disease during the postharvest storage of sweetpotato.