• Journal of Forest and Environmental Science
• /
• v.36 no.3
• /
• pp.207-218
• /
• 2020

Ashwagandha is an important ancient medicinal crops, being affected with many diseases, among which leaf blight caused by Alternaria alternata has become the constraint resulting in huge yield losses. Continuous usage of chemical methods leads to environment, soil and water pollution. Whereas biological control of diseases is long lasting, inexpensive, eco-friendly and harmless to target organisms. In this context, it is aimed to evaluate five Trichoderma strains viz. Trichoderma virens IMI-392430, T. pseudokoningii IMI-392431, T. harzianum IMI-392432, T. harzianum IMI-392433 and T. harzianum IMI-392434 as bio-control efficacy against A. alternata and growth promoting effect in Ashwagandha. All the Trichoderma strains had varied antagonistic effects against the pathogen. In dual culture technique, the strain T. harzianum IMI-392433 showed maximum percentage inhibition of mycelial growth (54.89%) followed by T. harzianum IMI-392432 (53.83%), T. harzianum IMI-392434 (48.94%) and T. virens IMI-392430, (43.62%) against the pathogen, while the least inhibition percentage was observed with the T. pseudokoningii IMI-392431 (36.60%). The culture filtrate of the Trichoderma strain, T. harzianum IMI-392433 recorded highest inhibition on the mycelial growth (39.05%) and spore germination (80.77%) of pathogen and the lowest was recorded in T. pseudokoningii IMI-392431 (20.45 and 50%). Moreover, seeds treated with spore suspension of the strain T. harzianum IMI-392433 reduced the percentages of disease severity index significantly. The strain T. harzianum IMI-392433 also significantly increased seed germination %, seedling vigor and growth of Ashwagandha. The correlation matrix showed that root yield per plant of Ashwagandha had significant and positive correlation with plant height (r=0.726^⁎⁎), number of leaf (r=0.514^⁎⁎), number of primary branch (r=0.820^⁎⁎), number of secondary branch (r=0.829^⁎⁎), fresh plant weight (r=0.887^⁎⁎), plant dry weight (r=0.613^⁎⁎), root length (r=0.824^⁎⁎), root diameter (r=0.786^⁎⁎), root dry weight (r=0.739^⁎⁎) and fresh root weight (r=0.731^⁎⁎). The significant and negative correlation (r=-0.336^⁎⁎) was observed with the root yield and percentages of disease severity index. The study recognized that the T. harzianum IMI-392433 strain performed well in inhibiting the mycelial growth and reduced the percentages of disease severity index of pathogen as well as increased the plant growth in Ashwagandha.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.21 no.2
• /
• pp.111-116
• /
• 2019

The biotic stress of garlic and tobacco infected by bacteria and virus was evaluated using a thermal imaging camera in a growth chamber. The remote sensing technique using the thermal camera detected that garlic leaf temperature increased when the leaves were infected by bacterial soft rot of garlic. Furthermore, the temperature of leaf was relatively high for the leaves where the colony-forming unit per mL was large. Such temperature patterns were detected for tobacco leaves infected by Cucumber Mosaic Virus using thermal images. In addition, the crop water stress index (CWSI) calculated from leaf temperature also increased for the leaves infected by the virus. The event such that CWSI increased by the infection of the virus occurred before visual disease symptom appeared. Our results suggest that the thermal imaging camera would be useful for the development of crop remote sensing technique, which can be applied to a smart farm.

• Research in Plant Disease
• /
• v.11 no.1
• /
• pp.77-79
• /
• 2005

Leaf blight of kudzu was found in Jeonbuk province in 2002. Water-soaked lesion appeared on leaves, and young stems and gray green blight sypmtom expanded from margin to main vine of leaves. As the disease became severe, blighted leaves and shoots turned dark brown and then collapsed. The causal pathgen showed initially white aerial mycelium and turned brown to gray. Mycelia were branched at 90o angles and multinucleate in one cell. It formed sclerotia on PDA. Slerotia were irregular, globose and 0.5~3.0 mm in diameter. The causal fungus of leaf blight was identified as Rhizoctonia solani Kuhn based on the cultural and morphological characteristics. This is the first report on leaf blight of kudzu caused by R. solani in Korea.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2002.11a
• /
• pp.42.2-43
• /
• 2002

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.121.2-122
• /
• 2003

Since the demonstration that the transgenic plants expressing tobacco mosaic virus(TMV) coat protein(CP) gene showed resistance to TMV infection, there have been numerous attempts to produce virus-resistant plant by introducing of a part of or modified viral genome. This study was conducted to investigate the characterization and variability of disease outbreak of transgenic potato(T-potato) with the CP gene of potato leaf roll virus(PLRV) in an isolated field from 2000 to 2002. In the field inspection, incidence of PLRV on T-potato showed only 3.5％, while non-transgenic potato(N-potato) revealed 13.4％. Infection rate of PLRV was considerably low on T-potato with 4.2％ compared to 15.4％ of N-potato in ELISA tests. Those of potato virus M, potato virus Y and potato virus X on both potatoes were not statistically different. Infection of potato virus A was not observed on both potatoes. Incidence of potato late blight caused by Phytopkhora infestans on T-potato and N-potato did not differ each other with 52.7％, and 50.8％, respectively, Mating type of the causal fungus isolated from both potatoes was all Al types. Results indicates that the CP gene of PLRV affects specifically to the virus in the transgenic potato.

• Korean Journal of Plant Resources
• /
• v.29 no.5
• /
• pp.625-629
• /
• 2016

A new Gomchwi cultivar ‘Gommany’ was bred by crossing between Gomchwi (Ligularia fischeri (Ledeb.) Turcz.) and Handaeri-gomchwi (Ligularia fischeri var. spiciformis Nakai). The selection and investigation of growth and yield characteristics were conducted from 2006 to 2011 in field and greenhouse of Highland Agriculture Research Institute, NICS, Rural Development Administration. The color of petiole ear was purple. Petiole trichome existed, but light of leaf back did not. Density of leaf vein was 5 degree in a newly developed cultivar ‘Gommany’. Plant height, leaf length, leaf width and petiole length were 47.7, 16.3, 21.2, and 31.4 ㎝, respectively in the 3 year of growth characteristics. Plant size was also higher than that of ‘Gondalbi’. Bolting and flowering time were Aug. 5 and Sept. 10, respectively. In contrast, Bolting time of ‘Gondalbi’ showed 25 days quite earlier bolting time compared to ‘Gommany’, Which led to earlier flowering time. ‘Gommany’ showed higher number of leaves (138) per plant compared to ‘Gondalbi’ (130). Furthermore, yield was 97% higher in ‘Gommany’ (1,575 g/plant) than in ‘Gondalbi’ (798 g/plant). ‘Gommany’ showed higher leaf thickness (0.69㎜) than ‘Gonalbi’ (0.46 ㎜), and consequently showed more hardness in leaf characteristics (24.3 ㎏/㎠) compared to ‘Gondalbi’ (23.0㎏/㎠). ‘Gommany’ showed higher resistance in the susceptibility of powdery mildew compared to ‘Gondalbi’. ‘Gommany’ cultivar was registered as a novel variety with number 90 in The Minister of the Korea Forest Service on December 2015.

• The Plant Pathology Journal
• /
• v.25 no.1
• /
• pp.103-107
• /
• 2009

In the course of a searching natural antifungal compounds from plant seeds, we found that the methanol extract of Psoralea corylifolia seeds showed potent control efficacy against tomato late blight caused by Phytophthora infestans and wheat leaf rust Puccinia recondita. Under bioassay-guided purification, we isolated two furanocoumarins, psoralen and isopsoralen, with anti-oomycete activity against P. infestans. By 1-day protective application, both compounds strongly reduced the disease development of P. infestans on tomato seedlings, but hardly controlled development of leaf rust on wheat seedlings. This is the first report on the anti-oomycete activity of P. corylifolia as well as that of psoralen and isopsoralen.

• Korean Journal Plant Pathology
• /
• v.12 no.2
• /
• pp.214-218
• /
• 1996

배나무잎 이상반점증상의 보독여부를 신속정확하게 검정할 수 있는 목본 지표식물을 선발하기 위해 시험을 수행하였다. 신고x조생적 등 5개 교배조합 102개체를 공시해서 1차로 10개체를 선발하였다. 1차로 선발된 개체중에서 전형적인 이상반점증상이 조기에 잘 나타나고 이상반점증상과 유사한 검은무늬병에 저항성인 신고$\times$조생적 86-2-2 계통을 최종선발하였다. 선발된 지표식물을 사용하여 농가포장에서 이상반점 증상의 보독여부를 실증시험한 결과 보독유무의 조기판별이 가능하였다. 이상의 결과에서 최종 선발된 신고$\times$조생적 86-2-2계통을 PS-95로 명명하고자 한다.

• Mycobiology
• /
• v.35 no.4
• /
• pp.235-237
• /
• 2007

Leaf blight and bulb rot symptoms were observed on narcissus plants grown in Yongin, Cheongwon and Namhae areas in Korea during disease survey from 1999 to 2002. A total of 15 isolates of Botrytis sp. were obtained from the infected plant parts of narcissus. All the isolates were identified as Botrytis narcissicola based on their morphological and cultural characteristics. Three isolates of B. narcissicola were tested for their pathogenicity to leaves and bulbs of narcissus by artificial inoculation. All the isolates induced leaf blight and bulb rot symptoms on the plants of narcissus by artificial inoculation. The symptoms induced by artificial inoculation were similar to those observed in the fields. This is the first report of narcissus smoulder caused by B. narcissicola in Korea.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
• /
• 2003.09a
• /
• pp.54-57
• /
• 2003

Implementation of disease-warning systems often results in substantial reduction of spray frequency (Lorente et al., 2000; Madden et al., 2000). This change reduces the burden of pesticide sprays on the environment and can also delay the development of fungicide and bactericide resistance. To assess the risk of outbreaks of many foliar diseases, it is important to quantify leaf wetness duration(LWD) since activities of foliar pathogen depend on the presence of free water on host crop surface for sufficient periods of time to allow infection to occur.(omitted)