| Research Abstract |
As the result of the ecological investigation, it was cleared that the infection source of black rot disease of chestnut fruit was the pycnospore or ascospore generated on the trunk and branches of withered chestnut tree due to black root rot disease by the black rot fungus secondarily infected and these spores were aerially disseminated to a chestnut bur. Therefore, in order to control the black rot disease, it is necessary to throughly perform the eradication of this infection source and the scattering of chemicals to the chestnut bur. As the result of the primary screening of 45 kinds of chemicals conducted for the purpose of the screening of chemicals effective against the black rot fungus, Benlate, Topsin M and Difolatan etc. were selected as effective chemicals. As the result of the investigation on the appearance of resistant pathogenic isolates to these effective chemicals, the appearance of resistant isolates was confirmed in all of the chemicals but Benlate or Topsin M resistant isolates were sensitive to Difolatan in most cases and, therefore, it was found out that the mixing use of Benlate or Topsin M and Difolatan was most effective. As the result of the investigation on the difference between varieties of the injuries of harvested fruits and stored fruits due to the black rot, a variety "Arima" showed strong resistance.
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