• Research in Plant Disease
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• v.11 no.1
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• pp.39-42
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• 2005

Powdery mildew, caused by Sphaerotheca aphanis var. aphanis, is an economically significant disease of strawberry in Korea. When powdery mildew is not controlled adequately, it often spreads rapidly through strawberry plants and damage is associated with reduced yields. Proper timing of fungicide applications is, therefore, essential for effective disease control. This study evaluated the efficacy by application schedule of fungicides before harvest stage for preventing powdery mildew in 2001-2003. The systemic fungicides, azoxystrobin, kresoxim-methyl, and cupper fungicide DBEDC were applied preventively during the first part of the cultivating season. Preventative applications of DBEDC by dipping treatment before transplanting and kresoxim-methyl by foliar spray before blooming stage were one of the most effective control schedule tested to prevent and manage this disease. This research demonstrated the significance of application time to control of powdery mildew, particularly provided elimination unnecessary sprays of agrochemicals and reduction costs for strawberry growers.

• The Korean Journal of Mycology
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• v.20 no.4
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• pp.309-314
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• 1992

Nine species of powdery mildew fungi were examined to understand the change in size of conidia in relation to air temperature. Of these, Sphaerotheca aphanis, S. fusca and S. pannosa showed constant value of conidial sizes regardless of changes in air temperature. The length/width ratio in the conidia of Erysiphe, artemisiae and E. sordida increased as the air temperature rose. E. cichoracearum gave the result against that shown in the above two species of Erysiphe. The conidia of Microsphaera pseudolonicerae became decreased in their width as the air temperature fell. The length/width ratio of conidia was markedly increased. M. alphitoides and M. robiniae showed variable size measurements in conidia regardless of changes in air temperature and studies for it needed for additional examination in future.

• Research in Plant Disease
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• v.14 no.3
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• pp.201-204
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• 2008

We've been involved in collection and domestication of Agrimonia pilosa from 2005 to 2007. We observed agrimony powdery mildew caused by Sphaerotheca aphanis. The powdery mildew developed twice a year, in May to June and mid August to September on whole plants of A. pilosa plants, that is, leaves, stem and floral part. We sprayed the Cooking Oil & Yolk mixture (COY) to control the agrimony powdery mildew. When COY was single-sprayed to control agrimony powdery mildew, its control value was 26.9%. However when it was double-sprayed and triple-sprayed at seven days interval, its control value increased up to 80.8 and 82.7%, respectively. Upon the first spray, symptoms of powdery mildew disappeared within three days and suppressive effect of COY was persisted for only seven days. Thereafter, powdery mildew was relapsed to develop. However, on double to triple sprays, powdery mildew was suppressed more than 28 days after final treatment. Therefore, it is concluded that double spray of COY at seven days interval can control effectively agrimony powdery mildew.

• The Plant Pathology Journal
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• v.21 no.3
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• pp.270-274
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• 2005

The aim of this study was to determine the effect of milk as one of the environmental friendly materials that substitute chemical fungicides for control powdery mildew (Sphaerotheca aphanis) of strawberries $(Fragaria{\times}ananassa\;Duch.)$. 'Maehyang' and 'Akihime' varieties planted in greenhouses were evaluated for the control of powdery mildew. Applications of $5\%,\;10\%\;and\;20\%$ milk had much better effects on controlling powdery mildew. In particular, $10\%$ milk showed a higher efficacy than other concentrations applied onto straw­berry in greenhouse experiments. Foliar spray application of $10\%$ milk was effective for powdery mildew, whereas drench application was not. Also, foliar spray of $10\%$ milk was able to accelerate more firmness and calcium contents of strawberry fruits than the non-treated. The $10\%$ milk applied with fertilizer salts $(Ca(H_2PO_4)_2-H_2O\;and KH_2PO_4)$ showed there was a similar efficacy to $10\%$ milk alone in greenhouse experiments. White crystals and cracks on strawberry fruits appeared by $20\%$ milk. This result indicated that $10\%$ milk was a useful substitute for fungicides to control powdery mildew of strawberry.