• Korean journal of applied entomology
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• v.41 no.4
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• pp.247-253
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• 2002

Based on accumulated data during 1977-2001, seasonal fluctuations of migrated aphids at Daegwallyeong highlands were analyzed. In addition, rates of PLRV transmission by migrated aphids were investigated by inoculation on indicator plant, Physazis floridana, and ELISA in 2000-2001, and the change of PLRV transmission rates by aphids was compared with that of 1989-1991. The average migrated aphid population densities in 1976-1980, 1991-1995, and 1996-2000 were 575.2, 2959.4 and 2281.6, respectively, showing gradual increase in recent years. The average peak time of aphid migration was from early to mid June during 1977-2001, showing any significant differences over the years. The dominant species, however, changed slowly; before mid 1980s M. persicae flied dominantly, but after mid 1980s Aphis gossypii did. Hahm et al. (1991) reported that PLRV transmission rate of migrated aphids during 1989-1991 was 6.7-10.0%. In 2000-2001, however, migrated aphids at Daegwallyeong highland showed 10.1-11.0%. Although present PLRV transmission rate was slightly higher than that of 10 years ago, taking increased population densities and diversity of migrated aphids into account, there was no significant change of PLRV transmission rate over the years.

• Plant Disease and Agriculture
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• v.1 no.1
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• pp.45-46
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• 1995

In recent years, there were considerably severe occurrences of TuMV(turnip mosaic virus) disease on radish and Chinese cabbage cultivated at alpine or sub-alpine regions, especially more severe on young Chinese cabbage sowed after late June. Started from 1991, those were very severe in 1992 and 1994, for the number of migrated aphids was increased enormously according to the weather condition of high temperature and low humidity then. This disease started at late June to early July, and continued to late August. It seemed that TuMV was transmitted easily and completely to the young chinese cabbages, but hardly and rarely the old. The regions over 1,000m of altitude had less possibility of disease-occurring, but there was severe occurrence on the second cropping of Chinese cabbage in a year. It is considered that more researches on control method of TuMV disease will be needed very urgently.