• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.255-265
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• 1996

토양에 존재하는 진균인 Gliocladium virens는 식물병을 감소 또는 방제할 수 있는 생물학적인 특성에 의하여 G. virens는 지난 수십년간 실용가능성이 큰 생물학적 방제균(또는 길항균)으로 집중적으로 연구되었다. 이 균이 식물병의 발생을 감소시키는 생물적 방제효과는 항생작용, 중복기생, 근권에서의 생존과 집단번식, 뿌리표면에서의 정착 등에 의한 것으로 분류되고 있다. 특히, 항생물질인 gliotoxin, gliovirin, viridin 등은 Rhizoctonia solani 및/또는 Pythium spp. 등에 항생효과가 뚜렷하고, 식물병의 발생과 직접적인 상관관계를 나타내고 있어 G. virens의 식물병의 방제에 관련된 중요한 작용기작으로 제시되어 있다. 또한, 근권에서 이균의 생존과 집단증식 및 뿌리표면에서의 정착은 식물병의 방제와 상관관계를 나타낼 수 있는 중요한 작용기작으로 제시되고 있다. 그러나 이균이 R. solani 등에 기생하는 현상은 식물병의 생물적 방제의 직접적인 연관관계를 나타내고 있지 않다. G. virens을 이용의 생물적 방제효과를 증진시키기 위한 방법으로 다음과 같은 두 가지 방법을 들 수 있다. 첫째, 길항효과가 높은 G. virens 균주를 선발하기 위하여 여러 종류의 토양에서 길항력이 높은 G. virens의 선발이 지난 수십년간 진행되고 있다. 또한, 특정 길항효과를 발현하는 유전자를 G. virens의 염색체에 도입하고 이를 발현시킴으로써 생물적 방제효과를 증진시키는 것으로 이러한 방법은 1980년 후반부터 진행되고 있다. 둘째, G. virens의 길항효과가 최대의 효율로 발현될 수 있도록 최적의 미세환경을 갖추고 있으며 농민이 편리하게 사용할 수 있는 G. virens의 운송매체의 개발이 중요하다. 운송매체의 개발에 의한 'Glioguard'는 G. virens의 포자를 alginate 입자에 제형화한 것으로서 미국에서 시판되고 있다. Aldicarb, metalaxyl, atrazine 등의 농약을 분해할 수 있는 능력은 G. virens의 다른 생물적 특성중의 하나이다. 특히, parathion을 분해할 수 있는 Flavobacterium sp.의 유전자(opd)가 G. virens의 염색체에 도입되여 발현될 수 있는 방법이 제시되었으며, 이는 G. virens을 이용한 토양에서의 특정한 농약의 분해효율을 증진시킬수 있는 가능성을 제시한 것이다. 그러나, G. virens를 이용한 농약의 생물적 분해에 관한 연구는 기초단계로 평가되고 있으며, 포장에서 이를 실용화하기 위해서는 향후 지속적인 연구가 필요하다.

• Research in Plant Disease
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• v.10 no.3
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• pp.159-166
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• 2004

This study were carried out to identify pathogens and determine the seasonal occurrence and chemical control of safflower (Carthamus tinctorius) diseases from 2000 to 2002 in Gyengbuk province, Korea. Major diseases of safflower were, anthracnose caused by Colletotricum acutatum in open field, and gray mold by Botrytis cinerea in rain sheltered plastic house. Other diseases occurred were powdery mildew caused by Sphaerotheca fuliginea, collar rot by Sclerotium rolfsii, leaf spot by Alternaria carthami and A. alternata, rust by Puccinia carthami, root-rot and stem-rot by Phytophthora cactorum, root-rot and wilt by Fusarium oxysporum and damping-off by Pythium ultimum. Seasonal occurrence of anthracnose on safflower has begun from late April, and increased until harvesting, especially rapid increased after rainfall during stem elongation season that is from May to June. In open fields, maximum incidence of anthracnose was 67 ％ in late July. But in rain-sheltered plastic house, it was very low, about 5％ in July. Gray mold caused by Botrytis cinerea was most important disease in rain-sheltered plastic house cultivation. Maximum incidence of gray mold on floral head was 27.4％, whereas other diseases occurred below 1 ％. In the test of the chemical control of the safflower anthracnose, metiram WP, carbendazim$.$kasugamycin WP and iminoctadintris$.$thiram WP were the highest controlling chemicals. In chemical control of gray mold, iminoctadintris$.$thiram WP, fluazinam WP and iprodion WP showed highest controlling effects.

• The Korean Journal of Pesticide Science
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• v.5 no.3
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• pp.18-25
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• 2001

Ethanol extracts from 46 plants were tested for their fungicidal activity against six plant diseases consisting of Maynaporthe grisea, Rhizoctonia solani, Botrytis cinerea, Phytophthora infestans, Puccinia recondita, and Erysiphe graminis in the greenhouse studies. Strong activity at 5 and 10 mg/pot was produced from the extracts of Helianthus annuus flowers and Zea mays leaves against P. grisea. In a test with B. cineara, extracts of H. annuus leaves, H. annuus flowers, Chrysanthmum coronarium var. spatiosum, Cucurbita moschata seeds, Lycopersicon esculentum, Z. mays, and Z. mays leaves had strong activities at 5 mg/pot. In a test with P. recondita, strong activity was obtained from the extracts of Capsicum frutescens, C. moschata seeds, H. annuus seeds, L. esculentum, and Malva veticillata at 5 mg/pot. Against E. graminis, extracts of Cucumis sativus, H. annuus seeds, Salanum tuberosum, Z. mays, and Z. mays leaves produced strong activities at 10 mg/pot. All the extracts were ineffective against P. infestans and R. solani. Among seven extracts tested, the extracts of H. annuus leaves and flowers were highly effective against all the strains of B. cinerea resistant to carbendazim, procymidone, and diethofencarb. Furthermore, potent fungicidal activity was produced from the extracts of C. coronarium var. spatiosum and C. moschata seeds against the SSR, SRR, and RSR strains of B. cinerea, and Z. mays and Z. mays leaves against SSR and RSR. Extract of L. esculentum showed very strong activity only against RRS of B. cinerea.

• Research in Plant Disease
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• v.20 no.1
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• pp.54-58
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• 2014

Anthracnose crown rot (ACR), caused by Colletotrichum fructicola, is a serious disease of strawberry in Korea. The primary inoculums of ACR were symptomless strawberry plants, plant debris, and other host plants. To effectively control anthracnose in symptomless transplanted strawberries, it is necessary to use disease-free plants, detect the disease early, and apply a fungicide. Therefore, in 2010 and 2011, we evaluated the efficacy of pre-plant fungicide dips by using strawberry transplants infected by C. fructicola for the control of anthracnose. Dipping plants in prochloraz-Mn for 10 min before planting was most effective for controlling anthracnose in symptomless strawberry plants and resulted in more than 76% control efficacy. Azoxystrobin showed a control efficacy of over 40%, but plants treated with pyraclostrobin, mancozeb and iminoctadine tris showed high disease severity. The control efficacy of the dip treatment with prochloraz-Mn did not differ with temperature and time. Treatment with prochloraz-Mn for more than an hour caused growth suppression in strawberry plants. Therefore, the development of anthracnose can be effectively reduced by dipping strawberry plants for 10 min in prochloraz-Mn before planting.

• Research in Plant Disease
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• v.18 no.4
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• pp.331-337
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• 2012

Citrus melanose is one of important disease in citrus cultivation, reducing quality of citrus fruits and resulting in economic loss. Like other diseases in citrus, melanose was mainly protected by chemical fungicide in the field. Recently, alternative method of disease control is highly required due to the side effect of the chemicals. In this study four rhizobacterial strains TRH423-3, MRL408-3, THJ609-3, and TRH415-2 are selected by dual-culture testing its antifungal activity against Diaporthe citri causing citrus melanose. To investigate the protection efficacy of the selected rhizobacterial strains to citrus melanose, the bacteria were pre-treated on citrus leaves following inoculation with melanose pathogen. Pre-treatment with all selected rhizobacterial strains showed disease suppression in which the levels of protection rates were different by the rhizobacterial strains. Additional treatment with the rhizobacterial strains after the pathogen inoculation enhanced protection rates in all cases. The strain MRL408-3 and TRH423-3 were identified as Burkholderia gladioli, TRH415-2 as Pseudomons fluorescens and THJ609-3 as Pseudomonas pudia as a result of analyzing the internal transcript spaces of the rhizobacterial strains rDNA. The selected rhizobacterial strains may be valuable as biological control agents in the environment-friendly citrus farm in which chemical application is limited.

• Research in Plant Disease
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• v.15 no.3
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• pp.248-253
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• 2009

Chitosan has an antifungal activity and is widely used for control of various plant disease and plants growth in the field in Korea. Disease control efficacy of two preparations (SH-1, SH-2) of mixtures of high and low (chitooligosaccharide) molecular weight chitosan compounds against tomato leaf mold caused by Fulvia fulva was investigated under plastic greenhouse conditions. Both SH-1 and SH-2 formulations displayed potent disease control activity in two experiments. The protective activity of both preparations was comparable to synthetic thiophanate-M. The persistence activity of the formulations was sustained until 21 days after application. Effective concentration of the chtosan compounds for disease control was 1,200 mg a.i./L. In pot tests, chitosan preparations, at a concentration of 600 mg a.i./L, promoted plants growth. These results indicate that the chitosan preparations have a potential as an eco-friendly natural fungicide for the control of tomato leaf mold and plant growth regulator.

• Research in Plant Disease
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• v.15 no.3
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• pp.217-221
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• 2009

Fludioxonil is derived from the antifungal compound pyrrolnitrin produced by Pseudomonas pyrrocinia and classified as a reduced-risk fungicide by the US EPA. The efficacy of fludioxonil for the control of lettuce gray mold caused by Botrytis cinerea was evaluated under several conditions such as growth stages of host, inoculum concentrations, and amounts of potato dextrose broth (PDB) included in spore suspension of B. cinerea. At 4-leaf stage of lettuce plants, fludioxonil applied at 2 ${\mu}g$/ml was more effective for the control of gray mold than at 5- and 6-leaf stages. However, fludioxonil at more than 10 ${\mu}g$/ml provided similar control activity in all growth stages of lettuce tested. The fungicide (10 and 50 ${\mu}g$/ml) also gave excellent control of gray mold on lettuce seedlings inoculated with spore suspensions of B. cinerea ($2.5{\times}10^5$ to $2{\times}10^6$ spores/ml). But, control efficacy of fludioxonil (2 ${\mu}g$/ml) was negatively correlated with inoculum concentration. Addition of PDB in spore suspension of B. cinerea resulted in higher disease severity than non-treated control. By inoculating spore suspension including 0.5% PDB, the fungicide gave the most control activity on the disease, followed by 1% and 2% PDB. The results suggest that fludioxonil has potential to control gray mold of lettuce, but the fungicide at a concentration having moderate activity may represent low control efficacy on the disease under some conditions.

• The Bimonthly Magazine for Agrochemicals and Plant Protection
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• v.12 no.1 s.100
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• pp.81-88
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• 1991

토양전염성 병을 효과적으로 방제하기 위해서는 병의 진단에서 부터 전염원 동태 파악, 발병환경구명등 기본적인 연구자료의 축적위에서 현행 방제법들을 적절히 조화시킨 종합방제 체제를 확립하여야 한다.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.237-244
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• 1996

길항곰팡이 3종(Aspergillus sp. A101, Penicillium sp. B202, Trichoderma sp. C303), 길항세균 3종(Arthrobacter sp. AN303)또는 이들 모두의 혼합균주를 배양하여 creeping bentgrass 양묘장에 처리하여 Pythium blight, brown patch 및 dollar spot의 방제효과를 조사하였다. 또한 길항미생물 6종의 배양액을 살균제와 병용하여 그린에 살포하여 이들 토양병에 대한 방제효과를 조사하였다. 양묘장에서는 미생물의 종류에 관계없이 Pythium blight 억제효과가 커 3회 이상 미생물제 처리시 병이 전혀 발생하지 않았다. 그러나 brown patch와 dollar spot은 미생물제에 의한 방제효과가 크지 않았으며, 살균제에 의해 효과적으로 방제되었다. 미생물제와 살균(Pythium blight 방제용 살균제 제외)를 병용하여 처리한 그린에서는 살균제 단독처리와 비교할 때 brown patch는 유의적으로 억제되었고 Pythium blight와 dollar spot은 차이가 없었다.

• Research in Plant Disease
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• v.8 no.1
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• pp.50-54
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• 2002

A total of 55 Colletotrichum isolates from strawberry plants with anthracnose symptoms(crown rot) were inhibited in mycelial growth on potato-dextrose agar(PDA) amended with fungicides in variable degrees depending on the chemicals used, especially showing no growth on PDA with 1 mg/m/tricyclazole. However, in the detached leaf test by treating chemicals before or after inoculation of Colletotrichum sp., tricyclazole was little effective in controlling symptom development; instead azoxystrobin, which had low in vitro inhibition of mycelial growth, inhibited strongly the symptom development. Some chemicals were tested for the control of strawberry crown rot in greenhouse using three methods, sprays soil drenching and plant dipping. No or little control effect were made by chemical spray and soil drenching, but plant dipping in chemical solution, especially azoxystrobin: reduced crown rot development by about 50% in the greenhouse suggesting that the azoxystrobin treatment may be an effective control method of the crown rot of strawberry. No differences in the control efficacy were noted according to the dipping time and chemical concentration of azoxystrobin not less than 10 min and 250 mg/m/, respectively.