• Research in Plant Disease
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• v.14 no.1
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• pp.68-70
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• 2008

Brown leaf spots on leaves of kiwifruit(Actinidia deliciosa) were observed at farmers' orchards in Suncheon and Goheung, Jeonnam Province, Korea in June, 2006. They developed to form dark brown ring spots and severely infected leaves resulted in defoliation during the growing season of kiwifruit. Alternaria sp. was isolated from the diseased leaves repeatedly and was identified as Alternaria alternata on the basis of its mycological characteristics on potato dextrose agar and its pathogenicity was confirmed by wound inoculation on healthy leaves of kiwifruit. A. alternata formed gray to dark sooty gray colony and produced numerous conidia on potato dextrose agar. The conidia, commonly in long chains of 5 or more produced on conidiophores, have $3{\sim}5$ transverse and $1{\sim}2$ longitudinal septa and mostly ovoid or obclavate in shape and were pale brown golden brown in color. The condia were $16.5{\sim}42.1{\times}6.7{\sim}19.5\;{\mu}m$ in size and conidiophores were $8.6{\sim}112.7\;{\mu}m$ in length. This is the first report on the brown ring spot on leaves of kiwifruit caused by A. alternata in Korea.

• Agrochemical news magazine
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• v.15 no.4 s.121
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• pp.42-45
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• 1994

• Agrochemical news magazine
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• v.19 no.4 s.145
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• pp.26-29
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• 1998

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2001.06a
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• pp.41-49
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• 2001

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.263-264
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• 2006

In this study, the threshold wind speed that causes physical damage on Kiwi fruit plant was investigated through wind tunnel experiments. Total 30 samples of Kiwi fruit branches were tested. On average, the wind speeds for tearing leaves and breaking side branch from the main branch were about 20m/s and 21.7m/s, respectively. For the cases of broken branches, the average length and diameter of the branches were 587.5mm and 7.2mm, respectively. The discoloration and dehydration of Kiwi plant were also observed by photographing leaves and branches after 24 hour later of the wind damage. In addition, the shelter effect of porous wind fences which have been used at agricultural districts was examined with varying several parameters.

• Korean Journal Plant Pathology
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• v.12 no.3
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• pp.324-330
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• 1996

암수 딴그루인 참다래 품종 중에서 우리나라에서 재배되고 있는 대표적인 결실수(암나무)인 Hayward와 수분수(숫나무)인 Matua에서 궤양병의 발생 차이를 조사한 결과 Hayward의 이병엽율은 18.0%인 반면에 Matua의 이병엽율은 2.4%였다. 또한 Hayward와 Matua의 잎에 형성된 병반에서 분리된 궤양병균의 균총수는 생체중 1 g당 각각 1.8$\times$10\ulcorner개와 2.1$\times$10\ulcorner개로 Hayward에서 Matua보다 약 10배 가량 많은 궤양병균이 검출되었다. Hayward 신초에 존재하는 궤양병균의 밀도를 조사한 결과 줄기 조직보다는 잎 조직에서 많은 궤양병균이 검출되었으며 새로 나온 잎일수록 궤양병균의 밀도는 낮게 검출되었다. 궤양병 방제를 위하여 스트렙토마이신 수간주입에 의한 궤양병 치료효과는 50.7~53.7%였다. 수간주입시 약량을 주당 2 L에서 3 L와 4 L로 증가시킴에 따라 치료효과도 32.3%에서 58.1%와 71.0%로 각각 증대되었는데, 수간주입 약제와 수간주입 방법의 개선을 통하여 궤양병 치료효과를 더욱 증대시킬 수 있을 것으로 기대된다.

• Journal of Life Science
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• v.21 no.4
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• pp.509-514
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• 2011

Maloactic fermentation (MLF) occurs after completion of alcoholic fermentation and is mediated by lactic acid bacteria (LAB), mainly Oenococcus oeni. Kiwi wine more than commercial grape wine has the problem of high acidity. Therefore, we investigated the optimal MLF conditions for regulating strong acidity and improving the quality properties of wine fermented with Kiwi fruit cultivated in Korea. For alcohol fermentation, industrial wine yeast Saccharomyces cerevisiae KCCM 12650 strains and LAB, known as MLF strains, were used to alleviate wine acidity. First, the various experimental conditions of Kiwi fruit, initial pH (2.5, 3.5, 4.5), fermenting temperature (20, 25, $30^{\circ}C$), and sugar contents (24 $^{\circ}Brix$), were adjusted, and after the fermentation period, we measured the acidity, pH, and the change in organic acid content by the AOAC method and HPLC analysis. The alcohol content of fermented Kiwi wine was 12.75%. Further, total acidity and pH of Kiwi wine were 0.78% and 3.5, respectively. Total sugar and total polyphenol contents of Kiwi wine were 38.72 mg/ml and 60.18 mg/ml, respectively. With regard to organic acid content, the control contained 0.63 mg/ml of oxalic acid, 2.99 mg/ml of malic acid, and 0.71 mg/ml of lactic acid, whereas MLF wine contained 0.69 mg/ml of oxalic acid, 0.06 mg/ml of malic acid, and 3.12 mg/ml of lactic acid. Kiwi wine had lower malic acid values and total acidity than control after MLF processing. In MLF, the optimum initial pH value and fermentation temperature were 3.5 and $25^{\circ}C$, respectively. Therefore, these studies suggest that establishment of optimal MLF conditions could improve the properties of Kiwi wine manufactured in Korea.

• Research in Plant Disease
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• v.9 no.3
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• pp.116-120
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• 2003

A PCR method that combines biological and enzymatic amplification of PCR targets was developed for the detection of Pseudomonas syringae pv. actinidiae on kiwifruit leaves. A nested PCR was performed with primers designes from the coding sequence of the cfl gene, which is involved in production of the phytotoxin coronatine. The first and second primer sets efficiently amplified expected 665 and 310-bp fragments, respectively. With two successive amplifications, as few as 20 CFU/ml of P. syringae pv. actinidiae could be detected on ethidium bromide-stained agarose gel. Leaf samples were collected from 4 kiwifruit trees showing yellow halo spots on leaves and incubated in pepton-sucrose broth for 12 h at $16^{\circ}$C before PCR amplification. Positive detection was obtained with one sample, which was proved as a diseased plant in the next spring.

• Korean Journal of Microbiology
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• v.43 no.4
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• pp.337-340
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• 2007

Pseudomonas syringae Pv. syringae is a causal agent of bacterial blossom blight of kiwifruit in Korea. Eleven strains of the pathogen were isolated from different kiwifruit orchards in Korea and the plasmid profiles were obtained by pulsed-field gel electrophoresis. They could be clustered into six groups according to the number and size of plasmids. The number of plasmids per strain and size of these plasmids ranged from 0 to 4 and from 22 to 160 kb, respectively. Among them, four strains belonging to Group III which harbored two plasmids were resistant to copper sulfate. Southern blot hybridization of the plasmid DNA indicated that the copper resistance determinant was carried on a 48 kb plasmid.

• Research in Plant Disease
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• v.8 no.4
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• pp.250-253
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• 2002

This research was conducted to develop a simple and effective method for pathogenicity assay of the causal agent of bacterial canker on kiwifruit. The developed method is a modified version of syringe-infiltration method that is used in the assay fer the hypersensitive response assay. Bacterial cell suspensions in 50 mM potassium phosphate buffer(pH 7.5) were infiltrated using a plastic syringe with 25G needle into primary leaves of five-year-old kiwifruit. Typical symptoms of bacterial canker were observed five days after infiltration. Symptoms developed on the leaves were detected in these inocula that treated above 10$^4$cfu/ml or above. Using this technique, host range of Pseudomonas syringae pv. actinidiae and three other plant pathogenic pseudomonads were investigated for 25 different plant species. The various symptoms were showed depend-ing on different plant species and inoculated pathogen combinations. This method has the advantage that symptoms can be showed faster compared to other methods and high humid conditions are not required.