• Research in Plant Disease
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• 제24권4호
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• pp.292-301
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• 2018

Alternaria leaf spot disease has been a concern during a tomato production in greenhouse. In vitro antifungal activities of vapours of four plant essential oils, cinnamon oil, fennel oil, origanum oil and thyme oil, were investigated during in vitro conidial germination and mycelial growth of Alternaria alternata causing the tomato leaf spots to find eco-friendly alternatives for chemical fungicides. The four plant essential oils showed different antifungal activities against in vitro conidial germination of A. alternata in dose-dependent manners, and cinnamon oil vapour was most effective to suppress the conidial germination. The four plant essential oils showed similar antifungal activities against the in vitro mycelial growth of A. alternata in dose-dependent manners, but low doses of thyme oil vapour slightly increased in vitro mycelial growth of A. alternata. Necrotic lesions on the A. alternata-inoculated tomato leaves were reduced differently depending on kinds and concentrations of plant essential oils. Delayed conidial germination and germ-tube elongation of A. alternata were found on the tomato leaves treated with cinnamon oil and origanum oil vapours at 6 hpi. These results suggest that volatiles from cinnamon oil and origanum oil can be provided as alternatives to manage Alternaria leaf spot during the tomato production eco-friendly.

• Mycobiology
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• 제29권2호
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• pp.107-109
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• 2001

Anthracnose symptoms severely occurred up to 50% on leaves of English ivy growing in greenhouses in Cheongwon area of Korea during disease survey in April, 2000. The symptoms developed as concentric spots with dot-like acervuli on leaves of the plant. A total of 24 isolates of Colletotrichum sp. were obtained from the spotted lesions and identified as Colletotrichum trichellum based on the morphological and cultural characteristics. Leaf spots similar to the original anthracnose symptoms were induced on the host leaves by artificial inoculation with the isolates of the fungus. This is the first record of C. trichellum causing anthracnose of English ivy in Korea.

• Korean Journal of Agricultural Science
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• 제7권2호
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• pp.77-80
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• 1980

Alternaria longissima Deighton & Macgarvie was recorded for the first time on seeds of sesame in low percentages. Detailed descriptions of the habit characters, conidial morphology and cultural characters are described. This fungus, which is generally regarded as a saprophyte, was shown to be a pathogen to sesame plants producing zonate leaf spots, foliage blight, stem necrosis and spots on capsules, but does not show any pathogenicity to rice and sorghum plants.

• Mycobiology
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• 제30권1호
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• pp.57-59
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• 2002

Anthracnose symptoms severely occurred up to 100% on leaves of May lily grown in four locations in Korea during a disease survey in 2001. The symptoms appeared as circular to irregular spots with brown to dark brown discoloration on leaves of the plant, and severely infected leaves blighted. A total of 35 isolates of Colletotrichum sp. was obtained from the spotted lesions and identified as Colletotrichum liliacearum based on the morphological and cultural characteristics. Leaf spots similar to the original anthracnose symptoms were induced on the host leaves by artificial inoculation with the isolates of the fungus. This is the first report that C. liliacearum causes anthracnose of May lily.

• Mycobiology
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• 제38권1호
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• pp.78-80
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• 2010

Leaf spot symptoms were frequently observed on yam plants grown in the Yeoju area in Korea during a disease survey in 2008. A total of five isolates of Pseudophloeosporella sp. were obtained from the infected leaves of yam plants. All of the isolates were identified as Pseudophloeosporella dioscoreae based on their morphological and cultural characteristics. A phylogenetic tree derived from the internal transcribed spacer sequences of the fungal isolates showed that the fungus is distinctly separated from species in other related genera. P. dioscoreae isolates caused very tiny spots on leaves of yam plants two weeks after artificial inoculation which were similar to those observed in the field. This is the first report that Pseudophloeosporella dioscoreae causes leaf spot in yams in Korea.

• Research in Plant Disease
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• 제17권3호
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• pp.410-412
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• 2011

Since the late 2000s, a serious Entomosporium leaf spot disease, caused by Entomosporium mespili, has been found frequently on leaves of Eriobotrya japonica and Photinia glabra at a nursery station in Goheung and Jeju, respectively. Studies were conducted to select fungicides that would effectively control Entomosporium leaf spot. Among the three fungicides tested, weekly foliar applications of propiconazole and chlorothalonil effectively reduced disease severity on E. japonica and P. glabra showing control value of 64.1% and 87.6%, respectively. Weekly treatments of thiopanate methyl were less effective. Propiconazole controlled the disease, but, it was phytotoxic to P. glabra.

• The Korean Journal of Mycology
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• 제30권2호
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• pp.173-175
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• 2002

Sooty leaf blight was found on Dendrobium sp. in several farmers' fields located in Namji-eup, Changnyeong-gun, Gyeongnam province, Korea in 2001. Symptoms of the disease appeared on leaves. Sooty leaf spots were started with amphigenous, subeircular to irregular spots, with light grayish brown to black color with definite margin lines on the upper surface of leaves. Infected leaves became defoliated and whole plants eventually were died. The infection rates of the disease in the surveyed area reached up to 64.8%, in the early September. Conidiophores of the causal fungus were dark grayish brown in color, densely fasciculate, straight, curved to sinuous, branched, $5{\sim}10$ septate and $63{\sim}164{\times}3.2{\sim}4.9{\mu}m$ in size. Conidia were pale to olivaceous in color, obclavatecylindric, straight to slightly curved in shape, $1{\sim}5$ septate and $46{\sim}98{\times}3.2{\sim}3.9{\mu}m$ in size. The optimum temperature for mycelial growth of the fungus was $25^{\circ}C$. The fungus was identified as Pseudocercospora dendrobii on the basis of its mycological characteristics. This is the first report on sooty leaf light of Dendrobium sp. caused by Pseudocercospora dendrobii in Korea.

• The Korean Journal of Mycology
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• 제44권3호
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• pp.201-205
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• 2016

In August 2015, leaf spot symptoms were observed on Korean gondre thistle (Cirsium setidens) in Youngwol, Korea. During the early stage, the symptoms appeared as one or more small gray-brown to brown spots on plant leaves. The spots showed extensive enlargement over time and eventually became large dark brown to black lesions on the whole leaf. Stemphylium species were consistently isolated from affected leaves. All isolates were identified as S. lycopersici, S. solani, or S. xanthosomatis based on morphological and cultural characteristics. The isolates were confirmed as S. lycopersici based on a multilocus sequence analysis using the ribosomal internal transcribed spacer (ITS) region, elongation factor 1, GAPDH (glyceraldehyde-3-phosphate dehydrogenase), and the noncoding region between the vacuolar membrane ATPase catalytic subunit A gene and a gene involved in vacuolar biogenesis. Pathogenicity was tested by spore suspension inoculation on wounded or unwounded gondre leaves. The lesions were observed on inoculated leaves within 3 days after inoculation, regardless of wound. To our knowledge, this is the first report of the leaf spot on gondre thistle caused by S. lycopersici in Korea or elsewhere.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제22권2호
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• pp.121-127
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• 1977

Leaf burning due to nitrofenapplication was characterized as brown color spot appearing on the leaf sheath and blade. The spots predominantly appeared around 5-7 cm high above soil surface regardless of different particle size, formulation, application method, or water level. Magnitude and frequency of burn spots increased somewhat as the granular size gets finer, by higher water level, or in transplanted rice compared to directly sown rice when applied at 7 leaf-stage, but there was no indication of increase in leaf burning due to clinging of floating dust to rice plant. When collections from local distributor's stock of TOK 7G, a granular formulation of nitrofen, were analyzed for particle size composition, 98.9% by weight ranged between 9 to 35 meshes, and only about 0.08% by weight was of particles finer than 100 mesh.

• Korean Journal of Medicinal Crop Science
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• 제23권2호
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• pp.150-154
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• 2015

Physiological disorders such as symptoms in leaf colored with brown spots are so many occurred in ginseng garden cultivated with paddy soil. This study was carried out to inhibit the symptoms of brown-colored leaf in 3-year-old ginseng by fertilizing calcium hydroxide [$Ca(OH)_2$] of 100 ~ 400 kg per 10a on paddy soil before transplant of seedling. Soil pH was rapidly increased, while Fe was decreased in soil by the increase of application level of calcium hydroxide. Soil pH was increased from 4.53 to 6.18 when calcium hydroxide was fertilized at level of 100kg per 10a. The content of Fe in ginseng leaf was decreased more than the control by fertilizing calcium hydroxide in soil. Ratio of brown-colored leaf and plant height and leaf area were decreased by the increase of calcium hydroxide. Ratio of survived root and yield of root showed the peak at the application level of 100 kg per 10a, and both of them were gradually decreased by the increase of calcium hydroxide. The decrease of missing plant rate above the application level of 200 kg per 10a had a negative effect on the decrease of yield of root.