• Korean Journal Plant Pathology
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• v.3 no.1
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• pp.17-19
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• 1987

• Weed & Turfgrass Science
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• v.5 no.1
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• pp.23-28
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• 2016

Zoysiagrass possessing the leaf yellowing with excessive tillers was first found in a golf course in Gyunggi province at last three to four years ago and since then have rapidly spread many golf courses in Korea. The symptom is very similar to that of yellow tuft or downy mildew, which is caused by Sclerophthora macrospora, on cool-season turfgrasses including Kentucky bluegrass and ryegrass. Microscopic study was firstly carried out to look over the presence of the pathogen in the infected leaf and stem tissues. Oospores and sporangia, reported as typical indicators of downy mildew, were obviously observed from the infected leaves. Using a set of primers based on the 18S ribosomal DNA from S. macrospora, the specific DNA fragment corresponding the gene was amplified. This study reveals that S. macrospora might be involved in spread of leaf yellowing of zoysiagrass with excessive tillers.

• The Plant Pathology Journal
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• v.18 no.2
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• pp.77-80
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• 2002

A simple method for sporangial formation of the rice downy mildew pathogen, Sclerophthora macrospora, on infected leaf tissues was developed to facilitate diagnosis of the disease. Freshly infected young leaves showing whitish to yellowish small spots were selected and cut into small pieces about 2-3 cm in length. About 10-20 pieces were surface sterilized in a 100 ml Duran bottle with 40 ml of 70% ethanol by vigorous shaking for 30 seconds. After washing three times with distilled water, the leaf cuts were submerged in 10 ml of Millipore-filtered paddy water and incubated at $20^{\circ}C$ in the dark. After 8-10 h of incubation, the bottle was vigorously agitated on a vortex mixer, Aliquot amount of the suspension, 0.1-1.0 m1, was spread on a slide glass and examined under a light microscope at 50 or 100x magnification. It was found that light and 1% NaClO strongly inhibit sporangial formation of S. macrospora. Meanwhile, the use of freshly infected young loaves and washing with 70% ethanol stimulated sporangial formation of the fungus on rice leaves.

• Research in Plant Disease
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• v.9 no.1
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• pp.52-56
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• 2003

It was conducted to investigate the effect of rice downy mildew (RDM) infection to plant growth and yield components in water seeding stage, and to screen of varietal resistance to downy mildew. Being infected by rice downy mildew, chlorotic spot appeared in the leaf and leaf length was shortened. As the infected rice was growing, internode was not elongated properly and was deformed, and then panicle was not arised or mal-formed. Plant height of infected rice was shortened at all growth stage, and while the number of tillers of infected rice was more decreased than that of healthy plant before maximum tillering stage, and that of infected rice was more increased after heading stage. While the number of internode of infected tiller was much increased than that of healthy tiller internode length of infected tiller was shorter. As the rice infected by RDM severely, the number of panicles per square meter and ripening of rice was more decreased and yield of rice was extremely much decreased. As result of the varietal resistance screening with rice seedling, Geyh-wabyeo and Donjinbyeo were resistant varieties to downy mildew.

• Korean journal of applied entomology
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• v.13 no.4 s.21
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• pp.232-234
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• 1974

Downey mildew was scarcely observed in the field until 1965. Now that downey mildew was found around Gimpo are3, Gyungi Province in 1966, the disease was found sporadically every where through the country. Since the disease was found on the recommended variety, Tongil, in 1971, it has been estabilished to be serious disease on Tongil, especially this year, 1974.

• Weed & Turfgrass Science
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• v.5 no.1
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• pp.17-22
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• 2016

Yellow tuft symptoms of a dense cluster on zoysiagrass (Zoysia japonica Steud.) occurred extensively at cultivated fields of zoysiagrass sods in Jangsung. The dense cluster of zoysiagrass showed significant morphological changes such as the tufts of shortening of internodes. The disease symptom was spread on a large scale throughout stolon nodes with multiple short leaves and it thrives in broom-like shaped clusters, exhibiting light green or yellow color on their leaves. The dense cluster of zoysiagrass had approximately 5.8 times more leaves on each node of its stolon then healthy zoysiagrass. Also, these zoysiagrass had poorly developed root and stolon caused by the tufts of a dense cluster of shoots. The dense cluster of zoysiagrass were collected for the putative causal agent incubation and upon close observation, it was found that the sporangia took the shape of a lemon, each sporangium was pointed at the end of its axis and was measured to be $60{\sim}96{\times}42{\sim}51{\mu}m$. These findings were analogous to the mycological characteristics of sporangia formed by the pathogen Sclerophthora macrospora. The symptoms of yellow tuft were prevalent in spring and autumn. Therefore, this study aims to present fundamental data in relation to yellow tuft on zoysiagrass in Korea.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.10a
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• pp.28.1-28
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• 1999